3201 Appendix C 151-182 Stse - Newfoundland And · APPENDIX C 152 BIOLOGY 3201 CURRICULUM GUIDE Important Note These STSE modules are intended for teacher reference. Each is designed

APPENDIX C

BIOLOGY 3201 CURRICULUM GUIDE 151

Appendix C

STSE

Science-Technology-Society and the Environment

APPENDIX C

152 BIOLOGY 3201 CURRICULUM GUIDE

Important Note

These STSE modules are intended for teacherreference. Each is designed to target specificoutcomes within Biology 3201.

APPENDIX C


Outcomes:1. Explain how the nervous system helps maintain homeostasis. (317-1)

2. Describe disorders linked to the nervous system and their effect on the homeostasis of the systemand the organism as a whole. (317-4)

3. Analyse how and why technologies related to the treatment of nervous system disorders weredeveloped and improved over time. (115-5)

4. Describe how the use of prescription and nonprescription drugs can have a role in maintaining ordisrupting homeostasis. (317-7)

5. Distinguish between questions that can be answered by science and those that cannot, andbetween problems that can be solved by technology and those that cannot. (118-8)

- Debate the merits of using drugs for treatments of nervous disorders against the long-termside effects.

6 Propose courses of action on social issues related to science and technology, taking into an arrayof perspectives, including that of sustainability. (118-10)

- Debate the legalization of certain drugs such as marijuana for medicinal purposes.

Drugs and Homeostasis

Introduction

Drugs have been considered invaluable to society asan instrument in the treatment of disease. Insulin isa hormone used to control diabetes. Chemotherapyuses drugs to destroy cancer cells. The use ofpainkillers such as Tylenol and antibiotics areprevalent in society. Prozac is a well-known drugused in the treatment of depression. Drugs havealso been considered a danger to society because oftheir inappropriate use and addictive nature. Manyhigh profile actors have admitted to drug andalcohol abuse such as Ben Affleck, Winona Riderand Robert Downey Jr. and have soughtrehabilitation for their addictions. This module willexamine the medical use of drugs in the treatment ofdisease, as well as their abuse in society. It will alsoexamine the long-term affects of drugs on the healthof the human body.

Neurotransmitters and the NervousResponse

Many drugs affect neurotransmitters.Neurotransmitters are chemicals secreted by neuronswhich stimulate motor neurons or neurons of thecentral nervous system. If you recall, a wave ofdepolarization is carried across a presynaptic neuronuntil it reaches the bulb-like ends of the axon. Theend of the axon contains the neurotransmitter in itsvesicles. Depolarization causes the calcium gates toopen and trigger the release of the neurotransmitterthrough exocytosis. The neurotransmitter diffusesbetween the synapse of the terminal end of the axonof the presynaptic neuron and the dendrites of thepostsynaptic neuron. The dendrites of thepostsynaptic neuron have specialized receptor sitesto which the neurotransmitter will attach. Theneurotransmitter will then either excite or inhibitthe neuron. Once a neurotransmitter has attachedto the receptor site of the postsynaptic neuron, anenzyme is released from the presynaptic neuron tobreak down the neurotransmitter.

APPENDIX C


Some neurotransmitters are excitory and includeacetylcholine, norepinephrine (noradrenaline),serotonin and dopamine. Other neurotransmittersare associated with relaxation such as dopamine andserotonin. Many neurotransmitters can havemultiple functions.

The drugs abused in society are typically stimulantsor depressants thought to block or enhance certainneurotransmitters. Diseases of the nervous systemare often associated with the improper functioningof a neurotransmitter or improper functioning ofthe enzyme used to break them down once they havebeen released and attached to the receptor site of thepostsynaptic neuron. Drugs can be developed tomimic the effects of the affected neurotransmitter orenzyme to treat these diseases.

Drugs in the Treatment of Disease

As just outlined, imbalances in neurotransmitterscan contribute to certain diseases. Several wellknown examples are Parkinson’s disease andHuntington’s disease. Parkinson’s disease isbelieved to be caused by a dopamine deficiency dueto the gradual death of the neurons that producedopamine. A dopamine deficiency can result intremors and rigidity in the limbs since messages cannot be sent between areas of the brain controllingbody movement.

Huntington’s disease is believed to be caused by amalfunctioning of an inhibitory neurotransmitter. Huntington’s is a genetic disorder characterized byjerky movements and loss of mental and emotionalabilities due to the destruction of neurons in certainareas of the brain.

Potential treatment is aimed at replacing thedamaged neurons in both of these cases through theexperimental use of stem cell transplants. Atpresent, other treatments involve targeting thedefective neurotransmitters such as increasingdopamine levels in Parkinson’s patients.

More and more research has shown that mentalillness is also a result of imbalances ofneurotransmitters. Mental illnesses were onceconsidered to have no biological basis but rather bedue to factors in an individual’s environment such

as experiencing stress or forms of mental andphysical abuse. At one time, sufferers of mentalillness were deemed as “weak-minded” and lackingthe skills to cope with life.

As science has progressed, genetic connections weremade with individuals in the same family sufferingfrom mental illness. This lead to the exploration ofa biological basis for mental disorders and resultedin a greater understanding by society regarding thecauses of mental illness. Mental illness is nowdiscussed more openly in society and is appreciatedas a medical condition.

Debate still continues regarding the issue of natureversus nurture in the onset of mental illness but allmust agree that the biological basis of mentaldisorders exists. The effective treatment of mentaldisorders with drugs also adds support to thebiological basis of these disorders. This next sectionwill explore the biological basis of certain mentalillnesses and the use of drugs in their treatment.

Clinical Depression Clinical depression is the most frequentlyencountered mental illness. Clinical depression isnow considered a physical condition in which thereis a fault in the brain chemistry. It may afflict up to5% of the population. Symptoms of depressioninclude a distinct change in mood accompanied byan extreme feeling of hopelessness. Other symptomsinclude: loss of appetite, weight loss, headaches,sleeplessness, loss of energy, tiredness, and anxiety. Suicide is common in about 15% of depressedpatients.

Serotonin, dopamine, and noradrenaline areneurotransmitters linked to clinical depression. Those suffering from depression either secrete toolittle of a particular neurotransmitter or too much ofthe neurotransmitter which is broken down byenzymes (monoamine oxidases) when it is reabsorbedinto nerve endings.

Three major classes of drugs are used in thetreatment of depression. They are monoamineoxidase inhibitors (MAOI’s) , selective serotonin re-uptake inhibitors (SSRI’s), and tricyclic compounds. Drug treatment is difficult because some drugs mayhave no effect and the patient may spend a period of

APPENDIX C


time searching for the proper drug and dosage thatmay help to alleviate the depression. It also takesseveral weeks for the drugs to take effect, if they areto work. In this time period, the patient could gointo remission or the condition may worsen. Theresult can be unrelated to the drug. These factorsmay make the treatment with drugs difficult and theprocess of finding a successful drug very lengthy. Itis unknown why the effect of drugs taken such alength of time or why some drug treatments aresuccessful and others are not. More research intothe causes of depression is needed in order to obtainmore successful treatment.

Tricyclic inhibitors appear to slow the re-uptake ofserotonin and noradrenaline.

MAOI’s are believed to inhibit monoamine oxidase(MAO). MAO is an enzyme that is believed tobreak down serotonin and noradrenaline. It hasbeen shown that enhancement of theseneurotransmitter systems leads to the elevation ofmood. A danger of MAOI’s and tricycliccompounds is the increased risk of heart failure. MAO inhibitors can not be taken with certain foodssuch as cheese, avocado, and wine because thisinteraction will raise blood pressure that can causeheart failure and death. Usually, doctors will avoidprescribing MAOI’s for these reasons. These drugscan also be lethal at relatively low dosages, which is aconcern for suicidal patients. Serotonin re-uptake inhibitors are the most widelyprescribed antidepressant. It appears to have fewerdangerous side-effects. A well known example isProzac. It functions by blocking serotonin uptakeand therefore increase the levels of serotonin at thesynapse. Side-effects include nausea, headache,insomnia and anxiety.

Bipolar DisorderBipolar disorder is also known as manic depression. Itaffects about 5 in 1000 people. It is characterized bysevere mood swings ranging from mania todepression, with normal periods in between. During a manic phase, individuals may think thatthey are invincible, behave recklessly or believe indelusions such as ones of fame. During thedepressive phase, the individual loses interest in

his/her usual activities, may sleep excessively orsuffer from insomnia. They may also be at risk ofsuicide during the depressive stage.

At one time, sufferers from manic depression wereunable to function in life normally. Fortunately,manic depression can now be treated with bothmedication and psychotherapy. The most commonmedication is lithium carbonate. It functions bymaintaining the chemical balances in the brain toprevent mood swings. Lithium appears to work inthe treatment of both mania and depression. This isbecause it is believed that the depressive phase is aresult of the preceding manic phase. If the manicphase can be controlled, then the depressive phasecan be controlled indirectly. Other drugs may beused to treat the symptoms of depression.

Unfortunately, the long term use of lithium canaffect the kidney and thyroid gland since lithiuminterferes with water and salt balance. There must beregular check ups to ensure that the lithium levels donot rise to a toxic level. Other side-effects of lithiumtreatment include: diarrhea, nausea, hand tremor,blurred vision, confusion, and swelling in the legsand feet. The side effects of this medication are whysome manic depressives are reluctant to continue useof lithium. Researchers and drug companies areworking to find better medications with less side-effects. In the meantime, patients are left with thedilemma of taking a medication that provides thebenefit of treating their mental disorder but can alsocreate grave concerns over some of its very seriousside-effects.

The causes of manic depression are still uncertain. There appears to be a genetic link and episodes canalso be triggered by stress. Chemical changes arealso being studied. Manic behaviour is believed tobe due to a high level of noradrenergic activity. This activity continues until the neurotransmittersystems are depleted. It is believed that lithium mayprevent mania by preventing noradrenalinedepletion.

SchizophreniaA greater understanding in society of schizophreniaas a mental illness was created by the award winningmovie, A Beautiful Mind. The movie focusses on thelife of John Forbes Nash Jr. and his struggle to copewith his mental illness. Nash was a mathematical

APPENDIX C


genius who later received a Nobel Prize inEconomics. Actor, Russell Crowe, plays Nash andportrays the symptoms of the disorder, as well asNash’s struggle. The primary symptoms ofschizophrenia include disturbance of thoughtpatterns, disturbance of affective reactions andautism or withdrawal. Secondary symptoms includehallucinations, delusions and paranoia. Thesesymptoms all represent a loss of contact with reality.This disorder appears at a rate of 1 to 2 percent inthe population.

There is a biological basis that predisposesindividuals to the development of schizophrenia. Aform of dopamine dysfunction, such as excessivedopamine activity, is believed to causeschizophrenia. Schizophrenic patients seem to havean excess number of dopamine receptors.

Chlorpromazine and related drugs have been used inthe treatment of schizophrenia and function inblocking the dopamine receptors. Unfortunately,the side effects are similar to Parkinson’s disease. Other side-effects include abnormal body and facialmovements and extreme pacing. If this occurs, eitherthe dosage is adjusted or a new medication isprescribed. Other side-effects include dry mouth,constipation, blurred vision and low blood pressure. Unfortunately, patients with schizophrenia are facedwith a similar dilemma as those with bipolardisorder. They must rely on a drug to treat theirdisorder and enable normal functioning in life, butit has difficult side-effects.

Commonly Abused Drugs

AlcoholAlcohol is probably the most commonly abuseddrug in society. Of all abused drugs, it is presentlythe only one considered legal upon reaching of age. It has been a large part of our culture for many yearsand is often associated with social functions andcelebrations. However, alcohol use definitely has itsdark side. It is known to alter personalities andcause people to behave in a manner outside theirnormal personalities. A night of abusing alcohol canlead to embarrassment and regret once the effectshave worn off. Poor judgment while drinking

alcohol can lead to making deadly decisions such asdrunk driving. Also, people have abused alcohol tothe extent they vomit in their sleep and choke todeath. Groups such as MADD (Mothers AgainstDrunk Driving) are advocating for the responsibleuse of alcohol.

Alcohol is usually considered to be a depressant butcan act as a stimulant in small doses. Alcohol affectsthe nervous system byincreasing the inhibitoryneurotransmitter GABA(Gamma Amici Biotypic Acid). It also modifies the effects ofanother excitoryneurotransmitter calledglutamate. A blood alcoholcontent of 0.10 can induceblurred vision, slurred speech,poor muscle coordination, andlack of rational judgment. A blood alcohol contentof 0.40 to 0.50 g/100 ml will induce coma and alevel of 0.60 will result in death. If a Newfoundlandand Labrador driver is found to have a BloodAlcohol Concentrate (BAC) of 0.05 g/100 ml,he/she receives a fine and a 24 hours suspension ofthe licence. If the driver is found to have a BAC of0.08 g/100 ml or greater criminal charges will belaid. Alcohol abuse can lead to short-term memoryloss and blackouts. It can irritate the gastrointestinaltract and increase hydrochloric acid production. Itslong-term use can also cause disorders such ascirrhosis of the liver and heart disease.

Alcoholism is considered to be a genetic andenvironmental disease that can lead to death. Alcoholism is associated with addictive personalitiesand may be a secondary result of depression. Severealcoholics often appear jaundiced due to cirrhosis ofthe liver. Their immune systems are impaired andthey are more prone to disease. There areorganizations such as Alcoholics Anonymous thatenable sufferers of alcoholism and their families tocope with this disease.

MarijuanaA Canadian Senate committee has proposal thelegalization of marijuana for non-medical use, citingthat it is less harmful than alcohol. They believe

APPENDIX C


that marijuana should be governed by the same lawsas alcohol. They believe legalization would allow forbetter regulation and taxation of the drug. Manyargue that prohibition of drugs such as marijuanasupports organized crime. It would also save moneyin law enforcement. This means that it couldpotentially be sold in corner stores. Others raiseconcerns about addiction and health concerns. There is also concern that it may be the “gateway” toabuse of more dangerous drugs. It is believed that ifmarijuana is legalized, more teens will abuse thedrugs because access would be easier. As a result ofthis, the Supreme Court of Canada has draftedlegislation that would decriminalize marijuanausage. Individuals possessing a small amount of thedrug would be fined much like a speeding ticket. Itis quite possible that within the lifetime of thismodule marijuana will be decriminalized.

Marijuana is derived from the Indian hemp plantCannabis sativa. The active compound inmarijuana, tetrahydrocannabinol (THC), works bybinding to CB1 receptorsfound on presynapticmembranes in the brain. These receptors function inblunting pain. THC alsocauses the release of theneurotransmitter dopaminewhich elevates mood andcontrols musclemovements. Thesebiochemical pathways can explain how the drugaffects its users and how it may also be used formedicinal purposes.

In low concentrations, THC causes euphoria. It hasthe ability of enabling the user to block out pain,frustration or confusion. There are also someserious health concerns regarding the use ofmarijuana. In high concentrations it can causehallucinations, anxiety, depression, and psychoticsymptoms. Smoking marijuana can cause lungcancer, sinusitis, and bronchitis. It increases thelevel of carbon monoxide in the blood which, inturn, reduces the amount of oxygen reaching theheart. Repeated use tends to lead to the inability todeal with everyday challenges. Long term use canresult in: impaired speech, memory loss, difficulty in

understanding complex ideas, insomnia, impairedvisual perception, and infertility. Marijuana use hasalso been linked to reducing immunity towardsdisease.

Marijuana has been demonstrated to have somepositive effects in the treatment of disease. It hasbeen used to treat medical conditions such as nauseain chemotherapy patients and to stimulate appetitein AIDS patients. It may also offer relief from painand reduce spasticity due to multiple sclerosis. It hasbeen shown to help sufferers of severe arthritis. Itcan be used as an anti-epileptic and anti-depressant. It is believed to be far less addictive than manyprescribed painkillers. Furthermore, it is believedthat marijuana could be manufactured in otherforms so that it does not have to be smoked andharm the lungs.

Regulations are now in place that permit sufferersfrom terminal illnesses and chronic conditions togrow and smoke their own marijuana. They mayalso designate someone to grow it for them. Atpresent, the Canadian Medical Society opposesmarijuana use for medicinal purposes because of thelack of clinical research. Debate continues amongthe medical community about prescribing the use ofmarijuana. The legal system, however, supports theuse of marijuana for medicinal purposes sincedenying an individual treatment that they believehelps their medical problem would be infringing ontheir human rights.

CocaineCocaine is derived from the plant Erthoxylon cocaand can be inhaled, smoked or injected. It results ina feeling of euphoria followed by depression.Cocaine acts by first stimulating the release ofnorepinephrine anddopamine and, in higherdoses, the release ofserotonin. Cocaine theninterferes with the re-uptake of theseneurotransmitters andthese neurotransmittersbuild up in the synapse. Prolonged use will causethe body to produce less

APPENDIX C


dopamine and the user will need more cocaine. Sideeffects include mental impairment, convulsions,hallucinations, stroke, heart attack and death.

HeroinHeroin is a highly addictive derivative of morphineand comes from the opium poppy, Papaversomniferum. Heroin is normally injected but canalso be snorted or smoked. It operates by binding toopioid receptors in the brain in which naturalchemical endorphins are involved in the relief ofpain. Heroin mimics the action of endorphins. After initial exposure users experience a surge ofeuphoria “rush” followed by a drowsy trance-likeslate. Prolonged use can cause less endorphinproduction. Side-effects include: depressedrespiration, impaired coordination, and decreasedtolerance to pain, long term effects can include:collapsed veins, infections of heart valves and liverdisease. Death can result from overdose.

RohypnolRohypnol is a drug associated with rave parties andcomes from the benzodiazepine family. It isconsidered to be the “date rape” drug and hasbecome infamous for its use in committing sexualassault. It is often given to unsuspecting victims bydissolving it in a beverage while they are unaware. Itis similar to ValiumTM but has ten times its strength.In combination with alcohol, it can be deadly.Rohypnol is highly addictive and induces severewithdrawal symptoms. Its use can cause deepsedation, respiratory distress, blackouts for up 24hours, and amnesia.

EcstasyEcstasy is known as Methylene Dioxy MethAmphetamine (MDMA) and has street names suchas X, Rolls, E, Adam,Beans and Buddies. Itis one of the designerdrugs associated withrave parties. WhenEcstasy first becamepopular, it was believedto be a “safe” drug withno side-effects. It was soon discovered, like manydrugs, to have deadly consequences with its abuse.

The initial use of ecstasy results in: increased heartrate, increased blood pressure, dilation of pupils andbronchi, brain stimulation, increased motor activity,tightening of jaw muscles, grinding of jaws,overheating, sweating, heat stroke, and dehydration. Complications can result in renal failure, depression,liver failure, cardiovascular collapse and respiratoryfailure to name a few. The long-term use of ecstasycan result in irreparable brain damage. Its use isknown to damage the brain cells that produceserotonin. In fact, long after ecstasy use, the nervefibres in the brain that were destroyed have grownback abnormally or not at all.

OxyContin OxyContin is a trade name for the drug oxycodonehydrochloride. It was developed in 1996 as a slowrelease pain reliever for people who suffer fromsevere or chronic pain. Because of its chemicalsimilarity to codeine, methadone and morphine, thissemisynthetic opiate works by acting as a centralnervous system depressant causing a range of effectsfrom analgesia to respiratory depression.

At the street level, OxyContin is often referred to asOxy’s, OC’s or Hillbilly Heroin. Most abusers ofthis drug avoid the slow release properties bychewing, snorting or injecting the medication to getan instant and intense “high”. Since itsintroduction, OxyContin abuse has caused adramatic rise in the incidence of overdose,emergency room treatment and death.

The short term effects of this drug are constipation,nausea, vomiting, lack of interest, dizziness, sweatingand weakness. However, the long term effects areprimarily addiction. OxyContin abuse is nodifferent from heroin, cocaine or alcohol abuse. The addict’s change their lifestyle to allow more andmore drug use.

APPENDIX C


Designer Drugs

Designer drugs are associated with undergroundhigh school and college parties called raves. Theyare called designer drugs because they are created byaltering the molecular structure of existing drugs toenhance their effects. They are prepared byunderground chemists known as “cookers”. “Cookers” are untrained and unlicensed chemiststhat work in poorly constructed laboratories. Ofcourse, these conditions offer little quality controland makes abuse of these drugs even moredangerous.

Designer drugs are derived from three differenttypes of drugs. These drugs are known as PCP,fentanyl, and amphetamine/methamphetamine. Thestreet drugs created from these drugs are known asXTC, Ecstasy, Adam, Eve, Lover’s Speed, GHB,Special K, Fantasy and Nature’s Quaalude. Fentanyl derivatives are known to be up to 1000times more potent than heroin. In general, designerdrugs can create a wide range of physical problemssuch as: hypertension, uncontrolled tremors, totalparalysis, seizures, permanent brain damage, anddeath.

Prescription Drugs

In recent years, concernhas arisen over theabuse of prescriptiondrugs. Someprescription drugs areeasily addictive andpatients can experiencedifficulty with withdrawal along with dangerous sideeffects. Some adolescents are becoming frequentabusers of prescription drugs due to the effects ofeuphoria that can be produced by these drugs. Crimes of breaking and entering pharmacies for thepurpose of stealing prescription drugs are on therise. There are three main prescription drugs thatare most commonly abused: Opioids, CNSdepressants and stimulants.

OpioidsOpioids are typically used to treat pain. Thesemedications fall into a class of narcotics and include

oxycontin, morphine, codeine and DemerolTM.Opioids function by attaching to specific proteinscalled opioid receptors. These receptors are foundin the brain, spinal cord and gastrointestinal tract. When opioids attach to the opioid receptors they areable to block the transmission of pain messages tothe brain. Opioids can produce a feeling ofeuphoria by affecting regions of the brain thatenable us to perceive pleasure. However, they canresult in physical dependence and addiction. Tolerance of opioids can result in the need to takehigher doses to achieve the same effect. Withdrawalwill cause: restlessness, muscle and bone pain,insomnia, diarrhea, vomiting, cold flashes, goosebumps, and involuntary leg movements. A largedose can lead to respiratory depression resulting indeath.

CNS DepressantsCNS depressants are often used to treat anxiety andsleep disorders by slowing normal brain function. Common CNS depressants include barbiturates andValiumTM. Most CNS depressants act on the brainby affecting the neurotransmitter gamma-aminobutryic acid (GABA). The function of GABAin the human body is to decrease brain activity.Therefore, increased doses will create the drowsyeffect required to treat anxiety and sleep disorders. Individuals can build a tolerance to CNSdepressants over time and require larger doses. Withdrawals can cause the opposite effects of thedrug. The mind can race out of control, possiblyresulting in seizures and other problems.

StimulantsStimulants are used to treat narcolepsy, obesity,depression, and attention-deficit hyperactivitydisorder (ADHD). These drugs enhance brainactivity and result in increased alertness, energy,elevated blood pressure, increased heart rate andrespiration. Examples of stimulants includeRitalinTM and DexandrineTM. The chemicalstructure of stimulants is similar to the chemicalstructure of the neurotransmitters norepinephrineand dopamine. Stimulants work by increasing theamount of these neurotransmitters to the brain. Anincrease in dopamine results in an increase in bloodpressure, increase in heart rate, constriction of bloodvessels, increase in blood glucose and it opens thepathways of the respiratory system. Stimulants do

APPENDIX C


not result in physical dependence or withdrawal. However, they can be used compulsively and highdoses repeatedly can lead to feelings of hostility andparanoia. High doses can cause body temperaturesto rise to a dangerously high level. They can alsocreate an irregular heartbeat leading to the risk ofcardiovascular failure. There is also the potential oflethal seizures.

Conclusion

Drugs can play a role in both maintaining anddisrupting homeostasis. When problems in theneurotransmitter balance occur, such as in the caseof mental illness, drugs can play a role in restoringthe balance. However, further study into the effectsof different neurotransmitters is essential to achievea better understanding of diseases caused byneurotransmitter imbalance. This can lead to betterdrug treatments that have less serious side-effects. Drug abuse can also disrupt homeostasis. Understanding the effects of drug abuse on neuralpathways and the overall health of an individual canaid in the education of individuals considering drugabuse. It can also aid in the treatment of thosesuffering from addiction. Understanding theseriousness of drug abuse on long-term health maymake one think twice about engaging in the legaland illegal use of drugs.

Questions

Understanding Concepts1. For each mental illness, (clinical depression,

bipolar disorder and schizophrenia) list theneurotransmitters involved, the nature of theimbalance of the neurotranmitter, the drugsused in their treatment, and side-effects of eachof these drugs. This may be done in the form ofa chart.

2. For each street drug, (alcohol, marijuana,cocaine, heroin, RohypnolTM, ecstasy andOxyContin®) list the effects on neuralpathways, the short-term effects of the drug andthe long-term effects of the drug.

3. What are the dangers of using designer drugs?

4. For each of the prescription drugs, (opioids,CNS depressants and stimulants) list the effectson neural pathways, the short-term effects of thedrug and the long-term effects of the drug.

Extensions1. Debate the pros and cons of the use of

marijuana in the treatment of chronic pain.

2. Debate the merits of whether or not to usedrugs for treatments of nervous diseases such asmental illness disorders despite the side effectsof these drugs.

3. Debate the merits of legalizing marijuana. Research the present legislation regarding thelegalization of marijuana.

4. Using the knowledge that you have gainedabout the causes of mental illness, respond tothe following statement: “Mental illness is afigment of one’s imagination and one canchoose whether or not to control his/herthoughts.”

5. Choose a drug of interest to research. Reportyour findings in the form of a magazine article.

6. Write a letter to an imaginary friend whom youknow is abusing drugs. In this letter, use whatyou know about the dangers of drug use topersuade them quit and seek help.

APPENDIX C


References

Bullard, Chetty et al. (2003). Biology. McGraw-Hill Ryerson. TorontoBrown, DeNeen L. (2002). Canadian Panel BackLegalizing Marijuana. WP Foreign Press. Available at:http://www.cannibisnews.com/news/thread14010.shtml

Common Drugs and Their Symptoms. Availableat:www.cornerdrugstore.org/CommonDrugsPage.htm

Drug Abuse: Chemical Changes in the Brain. Available at:www.epub.org.br/cm/n08/doencas/drugs/abuse06_i.htm

Drugs and the Nervous System. Available at:http://learn.dccc.edu/~saquilan/ppt/nervous/sld056.html

Drugs and the Nervous System. Available at:http://users,rcn.com/jkimball.ma.ultranet/BiologyPages/D/Drugs.html

Facts about Manic Depression. Missouri Councilfor Comprehensive Psychiatric Services. Availableat: www.parquad.org/mdfacts.htm

NIDA- Research Report Series – MarijuanaAbuse. Available at:wysiwyg://86http://www.nida.nih.gov/ResearchReports/Marijuana/Marijuana3.html

OxyContin Diversion and Abuse. National DrugIntelligence Center. January 2002.

OxyContin: Pharmaceutical Diversion. DEADrug Intelligence Brief. March 2002.

Research Report Series – Prescription Drugs:Abuse and Addiction. Available at:wysiwyg://143/http://www.nida.nih.gov/Re...hReports/Prescription/prescription2.html

Substance Abuse and Mental Health ServicesAdministration’s (SAMHSA), Drug Abuse WarmingNetwork (DAWN).

SANE. Available at:www.sane.org.uk/About_Mental_Illness/

The Nervous System. Available at:www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBoookNERV.html

Timmons and Hamilton. Drugs,Brain andBehavior – Ch. 6. Available at:www.rci.rutgers.edu/~lwh/drugs/chap06.htm

Timmons and Hamilton. Drugs,Brain andBehavior – Ch. 7. Available at:www.rci.rutgers.edu/~lwh/drugs/chap07.htm.

Wadler,Gary. Designer drugs. Available at:http://espn.go.com/special/s/drugsandsports/

APPENDIX C


APPENDIX C


Outcomes:1. Identify examples of technologies that were developed based on understanding of cell division. (116-

3)

2. Describe disorders linked to the nervous system and their effect on the homeostasis of the system andthe organisms as a whole. (317-4)

3. Analyse why and how technologies related to the treatment of nervous system disorders weredeveloped and improved over time. (115-5)

4. Select and integrate information on the application of technologies based on cell division. (213-7)

5. Construct arguments to support a decision, using examples and evidence and recognizing variousperspectives. (118-6)

6. Debate the merits of funding specific scientific or technological endeavors and not others. (117-4)

Stem Cell Research

Introduction

Imagine that your father has been diagnosed withParkinson’s disease and you begin to watch hiscondition deteriorate. Tremors become moreevident and his movements more rigid. He isunable to enjoy his normal day to day activities. Youfear how the debilitation of this disease will affecthis human spirit and you know the condition canonly get worse. You hear of countries in Europewho are transplanting embryonic stem cells in thebrains of Parkinson’s patients. It is a relatively newtreatment that is considered unethical in NorthAmerica due to the lack of research and the use ofembryonic stem cells. You begin to ask yourselfquestions about the ethical use of an embryo’s’ stemcells to treat your father. If you pursue thistreatment, will you be sacrificing the life of anunborn child for your father’s quality of life?

When does human life begin? The scientificcommunity, the pro-life movement and the pro-choice movement have debated this question for anumber of years. The onset of stem cell research hasadded another dimension to this debate. Is itmorally acceptable to cultivate cells from a humanembryo to cure a terminal disease? Where doscientists obtain these embryos? Should thetherapeutic cloning of an individual be permitted inorder to cure a disease of this individual? Whathappens to the embryo from which the stem cellswere retrieved? As these questions are being debated,

scientists are considering such scientific endeavors ashow stem cells can be used to understand and treatcancer. They are researching how stem cells can beused to treat spinal cord injuries and how stem cellscan provide a cure for Parkinson’s disease.

What are Stem Cells?

When the human egg is fertilized with sperm, all thegenetic information is in place to begindevelopment. Scientists are beginning tounderstand how a single fertilized egg cell can divideinto a multicellular organism with cells that havedifferentiated to perform a variety of purposes. Each of these differentiated cells has been derivedfrom a single cell and, despite performing differentfunctions, contains identical genetic information.Prior to differentiation, embryonic cells are knownas stem cells and have the ability to form any type ofcell in our bodies. The inner cell mass of theblastocyst contains stem cells that later differentiateinto the hundreds of specialized cells that make upthe human organism. In adults, stem cells can befound in tissue such as: the bone marrow, skin, liver,peripheral blood, blood vessels, muscle, and brain. The stem cells in adults are used to replace cells thatneed to be replaced through normal wear and tear,cells that have been damaged through injury, andcells that have been damaged through disease.

APPENDIX C


Cleavage

Stem cells have three unique properties. First, theyhave the ability to divide and renew themselves for along period of time. Secondly, they areunspecialized. Thirdly, they have the ability todifferentiate into specialized cells.

Types of Stem Cells

There are two main types of stem cells that scientistsare interested in studying: embryonic stem cells andadult stem cells. Embryonic stem cells can beobtained from the inner cell mass of the blastocystfour or five days after fertilization. Embryonic stemcells can be also derived from a five to ten week oldfetus. It is more common to use stem cells from theblastocyst rather than the fetus. Embryonic stemcells are considered to be pluripotent, which meansthey may eventually give rise to any type of cell inthe human body. Ethical issues arise from the use ofembryonic stem cells since the embryos are

destroyed and the debate continues to rage aboutwhen life begins.

Initially, adult stem cells were believed to mainlygive rise to the types of cells of the tissue for whichthey were found. However, recent research hasbeen exploring the possibility that adult stem cellsfrom one tissue may be able to differentiate into cellsof another tissue type. This is known as

APPENDIX C


transdifferentiation or plasticity. This is an area ofresearch that is rapidly advancing, especially since itavoids the ethical issue of using stem cells fromembryos. For example, hematopoietic stem cellsnormally give rise to all the types of blood cells. Recently, they have shown the ability to differentiateinto brain cells, skeletal muscle cells, cardiac musclecells and liver cells. Bone marrow stromal cellsnormally give rise to bone cells, cartilage cells, fatcells, and other types of connective tissue cells. However, recent research is showing that they maydifferentiate into cardiac muscle cells and skeletalmuscle cells. Brain stem cells can be shown todifferentiate into blood cells and skeletal musclecells.

If adult stem cells are able to demonstrate plasticity,then it is believed that liposuction could potentiallyprovide a source of stem cells since they have beenknown to reside in fat tissues. Discarded humanumbilical cords and human placentas could alsoprovide valuable sources of stem cells. In the future,a person could also be asked to donate his/her stemcells to be used later in life, if the need arises.

Present Research

Stem cell research began over 20 years ago whenscientists isolated stem cells from mouse embryos. Human stem cells were first isolated from humanembryos in 1998. These human embryos wereobtained through embryos that were produced forthe purpose of in vitro fertilization and were nolonger required by the donor for fertility purposes. In this case, the donor was required to provideinformed consent for their embryos to be used instem cell research. Scientists are presently trying to understand twomain properties of stem cells. First, they would liketo understand how stem cells can remainunspecialized for a period of time and renewthemselves for a period of years. Secondly, scientistswould also like to understand the signals thateventually cause cells to differentiate into specializedcells. Scientists believe that certain genes within acell must be “turned on” and other genes must be“turned off” to become these specialized cells. Thisfundamental knowledge would enable scientists todevelop treatment for diseases in which cells have

been damaged beyond the means of the body tonormally repair themselves.

Scientists have found that embryonic stem cells thatdivide within the laboratory, renew themselveswithout differentiating for a year or more. Thesame can not be said for adult stem cells at present.Scientists are hoping to understand the processesthat regulate stem cell division to remainunspecialized and proliferate compared to theprocesses that lead to the differentiation of cells. This knowledge can enable scientists to growembryonic and adult stem cells in the laboratorymore effectively. It has actually taken twenty yearsfor scientists to learn how to grow embryonic stemcells without them spontaneously differentiatinginto specialized cells. The ability to grow largenumbers of unspecialized cells in the laboratory iscritical to continued research.

Scientists believe that certain genes are found withinstem cells that produce internal signals that guidecell differentiation. They also believe that there areexternal signals that guide cell differentiation. Thesesignals include chemicals secreted by other cells,physical contact with neighbouring cells and thepresence of certain molecules. Understanding thesesignals can better enable scientists to learn how tocontrol the differentiation into the desired cell type.

Scientists are also learning to direct thedifferentiation of stem cells through a variety oftechniques. Such techniques include changing thechemical composition of the medium, altering thesurface of the culture dish or modifying the cells byinserting specific genes. The development andrefinement of techniques that control differentiationwill eventually lead to cells that can be transplantedto cure diseases such as heart disease, musculardystrophy and diabetes.

Finally, scientists are developing methods oftherapeutic cloning (also known as somatic celltransfer). Stem cells are created by transferringgenetic material from a transplant recipient into anegg cell. This egg cell is stimulated to divide andproduce stem cells that contain identical geneticinformation as the patient. However, this processhas resulted in several ethical debates. Does theproduction of these stem cells result in the

APPENDIX C


production of an embryo that is later destroyed? Isthis process essentially the cloning of an individual?

The Technique of Culturing EmbryonicStem Cells

Millions of stem cells can be cultured fromapproximately 30 cells taken from the inner cellmass of the blastocyst in about six months.

When the cells from the inner cell mass areremoved, they are transferred to a plastic laboratoryculture dish. This culture dish contains a nutrientbroth. The inner surface of the culture dish is coatedwith a feeder layer. This layer contains mouseembryonic skin cells that are treated so that they willnot divide. The feeder layer is important because itprovides the inner cells mass with a sticky layer towhich they may adhere. It also releases nutrientsinto the culture medium. The feeder layer of mouseembryonic stem cells does pose some problems inthat viruses and other macromolecules could betransmitted to human cells. Scientists are presentlydeveloping methods of culturing human stem cellsthat do not require the mouse feeder cells.

The stem cells will divide very quickly andovercrowd the culture dish. They will then beplated to other culture dishes. This process ofreplating will continue for about six months. Stemcells can be frozen and used later forexperimentation.

The Potential use of Stem Cells in theTreatment of Disease

As described earlier, stem cells are useful in researchbecause they are unspecialized cells that have thepotential to differentiate into specialized cells.

Specialized cells in the human body that have beendamaged through injury or disease could be replacedby stem cells if these stem cells can be induced to

differentiate into the cell type that has beendamaged. This is known as cell-based therapies.

For example, stem cells can potentially be used toreplace damaged cells of the pancreas that no longerproduce insulin. Stem cells could potentially replacethe nervous cells that have deteriorated in anindividual with Parkinson’s disease. There are agreat many other diseases and conditions that maybe treated through the success of stem cell research. They include: spinal cord injury, stroke, Alzheimer’sdisease, burns, osteoarthritis, rheumatoid arthritis,cancer, Purkinje cell degeneration, Duchenne’smuscular dystrophy, heart disease, vision loss, andhearing loss. Scientists are specifically working onthe directed differentiation of adult stem cells in thetreatment of Parkinson’s disease, diabetes and heartdisease. These specific cell types includedopamine-producing neurons, insulin-producingcells and cardiac muscle cells.

In Parkinson’s disease, a particular nerve cell orneuron called the dopamine-producing (DA)neuron has been degenerated or destroyed. Loss ofthe DA neuron leads to the tremor, rigidity and lossof mobility observed in Parkinson’s patients. Studies on mice, with Parkinson’s disease, indicatethat when dopamine-producing neurons weretransplanted into the brains of mice the symptomsof Parkinson’s were alleviated. Scientists are nowtrying to produce dopamine-producing neuronsfrom human stem cells for neurotransplantation ofParkinson’s patients. It is quite possible that withinthe lifetime of this module, a cure for Parkinson’sdisease could be found.

As the knowledge of how stem cells differentiateunfolds, a better understanding of diseases caused byabnormal cell division and differentiation such ascancer can be obtained and ultimately lead to a cure.Understanding these processes can also lead to theprevention of birth defects.

APPENDIX C


Mouse adult stem cells areinjected into the muscle ofthe damaged left ventricularwall of the mouse heart.

Mouse heart

Stem cells helpregenerate damaged heart muscle.

Adult stem cells

Damaged heart muscle cells

APPENDIX C


The use of stem cells in cancer treatment can have awide range of applications. Cancer cells and stemcells both have the ability to renew themselves. Understanding these processes can help scientistsunderstand why cancer cells resist aggressivetreatments and continue to proliferate. As well,cancer treatments such as chemotherapy can cause ahigh degree of damage to healthy cells and tissues inthe body. Stem cells can be used to restore theimmune system for aggressive cancer treatments. Embryonic stem cells could also be used to restorethe immune system of patients undergoing bonemarrow transplants. Stem cells may eventually be produced that areresistant to chemotherapy and therefore betterenable patients to deal with the effects ofchemotherapy. In addition, stem cells could be usedto create cancer vaccines by providing antibodiesagainst cancer cells.

The Benefits and Risks ofEmbryological Stem Cells and AdultStem Cells

Most of the debate around stem cell research centersaround the use of embryological stem cells asopposed to adult stem cells. Embryonic stem cellscan differentiate into any type of specialized cells. The plasticity of adult stem cells is only presentlybeing investigated and more research is needed todetermine how adult stem cells can differentiate intoother types of cells. Researchers have learned how toculture embryonic stem cells in large numbers forthe past twenty years. Adult stem cells are difficultto find in mature tissues and researchers have notdeveloped techniques to culture them in largenumbers.

The use of adult stem cells from a patient offers adistinct advantage in that this patient will not rejecthis/her own stem cells after transplantation. Notonly is the risk of rejection eliminated from thepatient’s immune system but alsoimmunosuppressant drugs will not be necessary. Ithas not been determined whether a patient wouldreject stem cells from a donor such as in the case ofthe use of embryonic stem cells.

There is the potential that stem cells derived froman embryo could contain viruses or diseases thatcould be transmitted to the patient. There is also aconcern that these stem cells lead to thedevelopment of tumors after transplantation.

Conclusion

Research on the use of stem cells is advancingquickly. Stem cell research has also gainedmomentum through the involvement of suchcelebrities as Michael J. Fox and ChristopherReeves. Stem cells could be used to replace thedamaged neurons in the brain of Parkinson’spatients such as Michael J. Fox. They could also beused to repair the damaged spinal cord tissue such asin the case of Christopher Reeves. Some, however,will argue that one should not devalue human lifefrom the moment of conception until death andthat it would be immoral to use embryonic stemcells in the treatment of disease. As of 2004, theCanadian Institute of Health Research hasdeveloped guidelines that prohibit cloning and theproduction of embryos strictly for researchpurposes. Research on embryos is only permitted ifthose embryos were developed for reproductivepurposes and they are obtained with full informedconsent.

The debate about the ethical use of stem cells rageson in society. In the meantime, researcherscontinue their work with stem cells from theexisting embryos produced through in vitrofertilization and are developing the possibilities fromadult stem cells. They must do this in the hope offinding successful treatments for disease anddamaged tissue while respecting the ethical issuessurrounding the debate of stem cell research.

References

Cohen, Elizabeth. Actor Christopher Reeve believesthat embryonic stem cell research will allow him towalk again one day. CNN Medical Correspondent

Hedrick, Marc (2001). Life Must Take Priorityover Research. Available at:http://www.prolifeinfo.org/stemcell038.html

APPENDIX C


NCIC Media Release. Human Embryonic StemCell Research Guidelines Announced TodaySupported by the Canadian Cancer Society and theNational Institute of Canada. Available at:http://www.neic.cancer.ca/pubs/media/02/mar4_e.htm

Text of Bush Speech on Embryonic Stem CellResearch. Available at:http://www.prolifeinfo.org/stemcell033.html

Public Funding of Stem Cell Research EnhancesLikelihood of Attaining Medical Breakthroughs. Stem Cells and the Future of RegenerativeMedicine. The National Academies. Available at:http://www4.nationalacademies.org.news.nsf/ibsn0309076307?OpenDocument

Stem Cells and Regenerative Medicine. TheNational Academies. Available:http://www4.nas.edu/onpi/webextra.nsf/44

Stem Cells: A Primer. Available:http://www.nih.gov/news/stemcell/primer.htm

The Center for Bioethics and Human Dignity. Available:http://cbhd.org/resources/overview/stemcell.html

Questions

Understanding Concepts1. Construct a table that outlines the benefits and

risks of using embryological stem cells comparedto adult stem cells.

2. What are the potential sources of embryologicalstem cells? What are the potential sources ofadult stem cells?

3. What are three properties possessed byembryonic stem cells that scientists find valuablein their research to use stem cells to treatdisease?

4. Describe what scientists know about the factorsthat cause the differentiation of cells.

5. What techniques have scientists begun todevelop that direct the differentiation of stemcells?

6. What is meant by cell-based therapies?

7. Describe the process of therapeutic cloning.

8. Briefly outline the steps used to culture largenumbers of embryonic stem cells.

Extensions1. Scientific research in the use of stem cells is

quickly advancing. This is an opportunity forstudents to update this module in response tothe latest research. Research the most currentfindings in any of the following areas:

• The use of embryological stem cells. Arescientists still using embryological stem cells? From where are these stem cells obtained? What are the present advantages offered bythe use of these stem cells? What are thepresent disadvantages offered by the use ofthese stem cells? If these types of stem arenot being used, why not?

• The use of adult stem cells. Are scientistsstill using adult stem cells? From where arethese stem cells obtained? What are thepresent advantages offered by the use of thesestem cells? What are the presentdisadvantages offered by the use of thesestem cells? If these types of stem are notbeing used, why not?

• The use of stem cells in cell-based therapies. What disorders are presently being exploredthat may benefit from stem cell research? Are there any disorders that are beingsuccessfully treated through the use of stemcells? Are these therapies usingembryological or adult stem cells? What aresome potential problems with thesetreatments?

• The use of stem cells in developing drugs. What type of research is taking place on thedevelopment of drugs to treat disease? Arestem cells being used successfully in thedevelopment of drugs to treat disease? If so,what types of diseases are being treated?

APPENDIX C


This research may be done individually or bystudent groups. Presentations may be a valuableway for students to share what they have learned.

2 Explore the latest stem cell research involvingthe treatment of a particular disease or disorder. Examples may include Parkinson’s disease,diabetes, spinal cord injury, stroke, Alzheimer’sdisease, burns, osteoarthritis, rheumatoidarthritis, cancer, Purkinje cell degeneration,Duchenne’s muscular dystrophy, heart disease,vision loss and hearing loss. This may bepresented in the form of a paper or classpresentation.

APPENDIX C


Outcomes:1. Predict the effects of mutations on protein synthesis, phenotypes, and heredity. (315-7)

2. Describe factors that may lead to mutations in cell’s genetic information. (315-6)

3. Explain the circumstances that lead to genetic disease. (315-8)

4. Demonstrate an understanding of genetic engineering, using knowledge of DNA. (315-9)

5. Describe and evaluate the design of technological solutions and the way they function, using geneticprinciples. (116-6)

6. Construct arguments to support a decision or judgment concerning the use of genetic engineering,using examples and evidence and recognizing various perspectives. (118-6)

7. Analyze and describe examples where genetics based technologies were developed and based onscientific understanding. (116-4)

8. Analyze from a variety of perspectives the risks and benefits to society and the environment ofapplying the scientific knowledge gained through the genetic research. (118-2)

9. Identify and describe science and technology-based careers related to the field of biotechnology. (117-7)

Genetics Research in Newfoundland andLabrador

Introduction

If you had the opportunity to help scientists cure aparticular disease, would you do so? Most peoplewould likely say, yes. There are many people acrossNewfoundland and Labrador who are doing exactlythat. They are giving consent to a local companycalled Newfound Genomics to use their DNA ingenetic research.

Newfoundland and Labrador has become the focusof some exciting research in the field of genetics inrecent years. Newfound Genomics Incorporated is abiotechnology company that was established inNewfoundland and Labrador in June 2000 to studyhow genes affect human health and disease. Genomics is the study of how genes apply to healthand disease.

Founder Populations

Newfoundland’s current inhabitants rose fromabout 20,000 to 30,000 immigrants from Ireland,Scotland and Southwest England between the late1600’s and the 1840’s, making those earlyimmigrants Newfoundland’s founding population. The allele frequencies changed because thispopulation was smaller than the original and did notcontain all genes of the parent population. This isknown as the founder effect. The population also grew largely from expansion rather than throughimmigration, which limited genetic diversity. Sucha population is known as a founder population. Certain genetic traits became more prevalent in thenew population while other traits were eradicated.This explains why, compared to other populations,there is a higher incidence of some diseases inNewfoundland and Labrador while some otherdiseases are rare or non-existent.

APPENDIX C


Newfound Genomics and their Research

Scientists at Newfound Genomics are presentlystudying some common diseases in Newfoundlandand Labrador. These diseases include obesity, type 2diabetes, inflammatory bowel disease andosteoarthritis. Their research includes clinical,environmental and genetic factors of these diseases. Future studies may include inflammatory arthritisand, respiratory, infectious and dermatologicaldiseases. They will also examine geneticrelationships between different diseases.

Genes and Disease

DNA in our cells is used to make proteins. Whengenes in our DNA are altered, the proteins producedby them are altered as well, and we become moresusceptible to disease. Some of these variations inthe genetic code are referred to as Single NucleotidePolymorphisms (SNPs). In the case of SNPs, anucleotide substitution has taken place in thegenome. Other variants in the genome includeinsertions and deletions in the nucleotide sequence. These are considered to be point mutations.

Some SNPs have already been identified asassociated with some diseases. The Affymetrix®and MassARRAY genotyping systems are two typesof technology discussed later that scientists are usingto determine if an individual possesses the geneticmake-up (SNP) that contributes to a particulardisease. Imagine that you can now provide a geneticscompany with a swab of your cheek cells and theycan use this technology to determine the presence ofvariation in your genome that can either diagnose aparticular disease or predict the onset of a disease.

Other SNPs have not been identified with anydisease. These SNPs may have no effect on thehealth of the individual or the SNP may have yet tobe connected to a particular disease. This is largelythe work that researchers at Newfound Genomicsare performing. They can examine the genome forSNPs and are hoping to make connections betweenindividuals with a particular SNP and a disease. Researchers can then examine the sequences ofnucleotides in these SNPs in more detail tounderstand their effect on disease.

A better understanding of the sequences of thesegenes can lead to a better understanding of thephysiological effects of their variations. This may,in turn, lead to the development of drugs that mayrestore the normal functioning of the affectedprotein. This is a more revolutionary way oftreating disease. Instead of treating the symptoms ofa disease, scientists are discovering the exact cause ofa disease in regard to the genetic variation. Determining the precise genetic cause and theaffected protein will likely greater enable scientists totreat the cause of a disease as opposed to thesymptoms.

Laboratory Technology

Scientists at Newfound Genomics obtain DNAsamples and supporting medical information frompatient donors. The DNA samples taken frompatient volunteers are either in the form of bloodsamples or buccal cells. Buccal cells are epithelialcells taken from the inside of the cheek. DNA isthen extracted from either the blood samples or thebuccal cells.

DNA Extraction

Laboratory technologists extract DNA using bloodcells or buccal cells. The DNA is extracted using akit from a scientific supply company.

In the case of blood samples, DNA extraction beginswith lysing the red blood cells and collecting thewhite blood cells. A solution (enzyme) is then usedto break down the lipid membranes of the cells andthe nuclei of the cells to release DNA. Anothersolution is used to remove protein from the DNAsample. The DNA is precipitated in alcohol. Afterdrying, the DNA is dissolved in a solution used toprotect the DNA from enzymes that cause shearing. In the case of buccal cells, the same procedure isused but does not include the red cell lysis step. After DNA extraction has taken place, freezers areused to store DNA at -86/ C for an indefinite periodof time for analysis and further study.

APPENDIX C


DNA Genotyping

Scientists will use the DNA samples to carry out aprocess called genotyping. This is considered to beanalysis using genetic markers. Researchers atNewfound Genomics are presently looking at genemarkers that could indicate the presence of a genesequence contributing to a particular disease. Agene marker is a specific portion of a chromosomethat lies near a particular gene or is part of aparticular gene that is being studied. Once the genemarker is identified, a probe can be developed tosearch for the gene marker in other DNA samples.This probe consists of a DNA sequence that iscomplementary to the sequence of the gene marker. Sometimes this probe also contains a radioactive orfluorescent chemical tag so it can easily bedetermined if it bonds to the gene marker.

Newfound Genomics uses three methods ofgenotyping:

Basic Molecular Genotyping This involves a PCR reaction to amplify DNA. Specific primers have been developed for thevariant to be examined in the genome.

Gel electrophoresis is then used to determine ifthe variant is present. In gel electrophoresis, a2% agarose gel is used with ethidium bromide(EtBr) stain to adhere to the DNA. The EtBrwill illuminate with UV light. If the variant ispresent in the DNA sample, then the primerwould have enabled the DNA to amplify andthe EtBr would bind to the DNA and would beevident in UV light.

This is a more time consuming method ofgenotyping and tends to be used with smallprojects. With the new MassARRAYtechnology recently implemented at NewfoundGenomics, it will likely be used less often.

Affymetrix® GenotypingThe Affymetrix® technology will perform ageneral scan of the genome. It contains a genechip that has the capability of scanning for thepresence of SNPs. The Affymetrix® System atNewfound Genomics has a gene chip that can search for 1500 SNPs. A chip is presently beingdeveloped that can scan for 10 000 SNPs. As

discussed earlier, it can be used to determine if aSNP known to contribute to disease is presentor to make connections between the presence ofSNPs and the appearance of a disease.

The Affymetrix® technology can also be used ingene expression studies. In gene expressionstudies, scientists are examining particular genesthat may be “turned on” or “turned off” duringthe different stages of a disease.

The Affymetrix® technology incorporates PCRinto its technology. It will use probes in itstechnology to search for genetic markers. It alsouses fluorescent chemical tags in other aspects ofits technology to detect the presence of geneticmarkers.

MassARRAY Genotyping The MassARRAY technology is more specificthan the Affymetrix® technology and cancompare a greater number of parameters forexperimental work. The MassARRAY willanalyze genetic samples for a particular SNP or anumber of SNPs. It is capable of examiningfrom either the entire genome, several areas ofthe genome or one specific area of the genomefor a SNP. It can examine the geneticinformation for one individual or manyindividuals for one or many SNPs. In addition,it can examine and compare a large number ofindividuals for SNPs. Like the Affymetrix®technology, it is useful is making the connectionbetween the presence of a SNP and a disease. Itcan also examine the genome for the presence ofSNPs that are known to be related to disease.

The MassARRAY also incorporates PCR into ittechnology in addition to the use of primers. Sequenom Inc, a partner of NewfoundGenomics, developed this technology.

Ethics

All studies at Newfound Genomics are approved bythe HIC (Human Investigations Committee) at theFaculty of Medicine. Donor volunteers are requiredto give their full informed consent. This consentallows researchers to use the donor volunteers’ DNAfor one particular study, or it may allow researchersto use a donor volunteers DNA for similar studies

APPENDIX C


later. All participants must be volunteers since it isconsidered unethical to purchase body fluids inCanada. Newfound Genomics does not provideindividual feedback to participating volunteersregarding their specific genetic makeup. The geneticinformation obtained is pooled with informationfrom all participating volunteers with a similarmedical condition.

The main ethical issue concerning the use of donorvolunteers’ DNA deals with privacy. Newfound Genomics does not provide insurancecompanies nor employers’ access to DNAinformation to protect the privacy of theirvolunteers. It is expected that the type of researchdone by Newfound Genomics can determine thepresence of genes that may contribute to certaindiseases. One may ask, if insurance companies wereable to access this kind of information, would itlikely influence decisions regarding the issuing of lifeinsurance policies? If employers were aware that anemployee or a potential employee had the geneticmake-up that would likely lead to the developmentof a debilitating disease, would they make anunfavorable decision regarding the future orcontinued employment based on this information? As scientists continue to uncover the connectionbetween genes and disease in the hope of bettermedical treatment, it is conceivable that there areother agencies such as businesses that may use thisknowledge to further their own interests. This iswhy genomics companies are careful to ensure theconfidentiality of those who volunteer the use oftheir DNA to further the interest of science, and willdevelop their own codes of ethical conduct toreassure volunteers and the public about the natureof their research.

The Business Community

Newfound Genomics must act as an instrument ofscience but also must operate in the business world. It is important that their research is properlyfinanced. The company is focusing on 3 lines ofbusiness; novel gene discovery, validation studies,and laboratory services. It is also important that

Newfound Genomics does not work in isolationfrom other genetic research companies and academicinstitutions. For example, Newfound Genomics hasdeveloped a partnership with Memorial University,working to build research capacity and joint researchinitiatives.

Once Newfound Genomics discovers genes that areresponsible for the development of certain diseases,they will patent the use of this information for thedevelopment of drugs and diagnostic applications. Itis predicted that drugs developed from genomicsresearch will represent between 30-50% of globaldrug revenues by the year 2020.

Genetic companies are cautious regarding theownership of genetic information. For example, ifyou are patenting DNA, is it then the property ofthe individual who volunteered the use of theirDNA that is being patented? Do genetic companieshave the right to patent DNA if it can be argued it isthe property of the donor? If DNA is patented, thendo those who volunteered their DNA have a right toreap the economic benefits of the research? Imaginehow difficult it could be for genetic companies toexist as business institutions if all those who donatedtheir DNA were provided royalties based on thesuccess of the research. Furthermore, is it ethical forone to sell ones DNA for research or for companiesto buy it?

Careers in Biotechnology

At present, Newfound Genomics is located in St.John’s and on the west coast of the province andemploys about 10 people. Newfound Genomicscollaborates with Memorial University in thetraining of scientists, students and health careprofessionals for research. Their intention is toadvance the academic, intellectual, social andeconomic benefits for this province. It is expectedthat genetics research will be a fast growing industrydue to the unique genetic make-up of this province. It will, therefore, offer employment opportunities topeople in this province.

Conclusion

Newfound Genomics is an established and well-recognized biotechnology research company with a

APPENDIX C


number of research projects underway. Although itis too early for major results, any findings at presentare kept within the domain of the company. In fact,the company will not release any findings until theyare published and have undergone a peer review. This is because the information is considered“intellectual property” and it must remain private sothat Newfound Genomics can reap the academicand financial benefits of their work. It will beinteresting to see the extent of the development ofbiotechnology and genetics research in our provinceand to anticipate the benefits for Newfoundland andLabrador both economically and medically.

References

Lana Hays. Introduction to DNA Extractions. Available at:http://www.accessexcellence.org/AE/AEC/CC/DNA_extractions.html

Bullard, Chetty et al. (2003). Biology. McGraw-Hill Ryerson. Toronto

Newfound Genomics. Website available at:www.newfound-genomics.com

Government of Canada. Family Genes hold theKey to Understanding Disease. Follow the Leader.

Sequenom SNP Genotyping Technology. Availableat: www.sequenom.com

To Know Ourselves. US Department of Energy,Office of Health and Environmental Research. Available at:www.ornl.gov/hgmis/publicat/tko/index.htm

Special thanks to Hilary Vavasour, RN, RSCN, SCMwho provided a tour of the facilities at NewfoundGenomics and answered many questions regardingtheir work.

Special thanks to Lynette Peddle, BSc who took thetime to explain the technological aspects of NewfoundGenomics.

Questions

Understanding Concepts1. Outline the benefits, both medical and

economic, of genetics research in this province.

2. What is a founder population? How does itlend itself to genetics research?

3. Why are researchers looking for geneticmarkers?

4. What are some of the long term goals ofNewfound Genomics?

5. Why is it important to study genes in relation todisease?

6. What are some of the benefits offered toNewfound Genomics by their partnership withother biotechnology companies?

7. What is the benefit of using Affymetrix® andMassARRAY technology ?

8. Give two reasons why Newfound Genomicsdoes not release the results of their research untilthey are published.

Extensions1. Go to the website for Newfound Genomics

(www.newfound-genomics.com) and follow thelinks to “About Us” and “Our Team”. Examine the educational background and workexperience of the Newfound Genomics teammembers. Make a list of 15 items that describethe qualifications and work experience requiredto work in the field of biotechnology. Whatconclusions can you make about this list?

2. Why is it important that Newfound Genomicsassures their patient volunteers that access totheir DNA from outside groups will beprotected?

APPENDIX C


3. Consider the following issues:

a. Do you want to know if you will sufferfrom a genetic condition later in life?

b. Do employers have the right to knowyour genetic status? Insurancecompanies?

c. Who should have ownership of geneticinformation?

4. Research how you may carry out a DNAextraction using a DNA source such as onioncells, a blender, salt, detergent, meattenderizer and ethanol. What is thereasoning behind the use of each of thematerials used in this type of DNAextraction?

APPENDIX C


Outcomes:1. Outline evidence and arguments pertaining to the origin, development, and diversity of living

organisms on Earth. (316-4)

2. Explain the role of evidence, theories and paradigms in the development of evolutionary knowledge. (114-2)

3. Explain how knowledge of evolution evolves as new evidence comes to light and as laws and theoriesare tested and subsequently restricted, revised or replaced. (115-7)

4. Construct arguments to support a decision or judgment, using examples and evidence and recognizingvarious perspectives. (118-6)

5. Identify new questions that arise from what was learned. (214-17)

6. Use library and electronic research tools to collect information on a given topic. (213-6)

Extraterrestrial Life: Myth or Reality

Introduction

Imagine if somewhere in our galaxy, or beyond,organisms resembling intelligent life existed. Whatif extraterrestrial beings, such as Vulcans andKlingon Warriors of Star Trek, actually roamedaround outer space? Many scientists believe that lifecould possibly exist on other planets. Exobiology, orAstrobiology, is a branch of biology that studies thepossibility of life beyond Earth. Support forExobiology can actually be found using ourknowledge of how life has formed and evolved on

Earth. Since the last century, numerous expeditionshave been made and probes have been sentthroughout our solar system in search ofextraterrestrial life. On Earth, radio-communicationis used to send signals into outer space in the hopesof reaching intelligent life. Radio-telescopes areused to detect signals from extraterrestrials. Thismodule uses what is known about the origin andevolution of life on Earth to examine the possibilityof extraterrestrial life. The Origin of Life on Earth

The Big Bang Theory attempts to explain how thesun and planets in our universe were formed. Itstates that at one time our entire universe wascompressed into one atomic nucleus. Between 10-12 billion years ago an extraordinary explosion,trillions of degrees in temperature, blew apart theuniverse and it has been expanding ever since. Swirling clouds of dust condensed in the center ofour solar system to form the sun and swirling cloudsof dust and ice that orbited the sun came together,through gravity, to form the planets.

Earth probably formed about 4.5 billion years ago. At first, the atmosphere probably containedhydrogen gas. Later, volcanoes likely created an

APPENDIX C


atmosphere that was made up of carbon monoxide,carbon dioxide, nitrogen, water vapour and possiblymethane and ammonia. Oxygen was not present inthis atmosphere. It is important to consider thisbecause oxygen is considered to be an oxidizingagent that would disrupt chemical bonds. Thiswould prevent the formation of organic moleculesand, therefore, life as we know it.

In the 1920’s Haldane-Oparin hypothesized thatinorganic molecules can be used to make organicmolecules. They predicted that the components ofEarth’s early atmosphere could spontaneouslydevelop into organic compounds in the presence ofan energy source. Gases containing hydrogen,ammonia, methane and water vapour condensed toform pools on Earth’s surface known as primordialsoup. This mixture spontaneously produced organiccompounds when it was exposed to lightning andultraviolet radiation. These organic compoundsevolved over a long period of time to produce earlylife forms.

Further support for the Haldane-Oparin hypothesis,was provided by the experiments of Miller and Ureyin 1953. Miller and Urey designed an apparatusthat combined methane, ammonia, water vapourand hydrogen. They exposed these gases to anenergy source that simulated lightning. Theydiscovered that urea, amino acids and other organiccompounds were produced.

As a result of the work done by these scientists, it isbelieved that the atmosphere is composed of gasesthat could produce organic compounds. These gasesare carbon dioxide, nitrogen, water vapour, andsmall amounts of hydrogen and carbon monoxide. It is also believed that submerged volcanoes anddeep sea vents played a greater role in chemicalreactions than lightning and UV radiation. In fact,one of the earliest life forms on earth are Archaebacteria found in hot springs, nourished by thethermal vents of the Earth’s molten core.

Scientists believe that early life forms originatedfrom small organic molecules called monomers. Organic molecules then advanced to polymers suchas nucleic acids and proteins. It has been found thatclay can be used to polymerize reactions in whichmonomers can be joined into polymers. Scientists

suggest that monomers may have splashed from theoceans onto lava or other hot rocks, bondedelectrically to the rocks and then polymerizedthrough catalysts such as iron and zinc in the rocks.Monomers and polymers may have formedaggregates and developed forms of heredity andreproduction.

The first organisms probably came into being about4.1 billion years ago when Earth’s crust firstsolidified. Evidence of ancient prokaryotic fossilscalled stromatolites dates back to 3.5 billion yearsago. The stromatolites were likely photosyntheticbut heterotrophic life forms probably existed 4billion years ago. Earth would have required areducing atmosphere as opposed to an oxidizingatmosphere (which would have had existed at thetime of the photosynthetic stromatolites). Areducing atmosphere would add electrons tomolecules, thereby enabling simple molecules toform more complex molecules. Eventually, thesecomplex molecules became enclosed in membranesand the first organisms appeared.

Another theory, the Panspermia theory, explainedthat life originated elsewhere in the universe andsomehow found its way to Earth by intelligentbeings or by chance, such as by meteorites. The factthat rocks have traveled from Mars to Earth lendssupport to this theory. It is also known thatmicroorganisms can remain dormant for a longperiod of time and survive under space conditions.Therefore, it seems possible that microorganismsfrom Mars or from meteors could have reachedEarth and survived.

Based on these theories, scientists have beenexploring space for possible clues to the existence oflife. They have been looking for an atmospheresimilar to Earth’s early atmosphere. They are alsolooking for water, organic molecules, and an energysource such as the sun or volcanoes.

Extreme Environments on Earth

Life was not believed to have existed in extremeenvironments until recent years. These extremeenvironments include temperatures below zero andtemperatures of near boiling. They include milesabove in the atmosphere and miles beneath Earth’s

APPENDIX C


surface. Spores can hibernate for centuries andflourish when water reenters the environment. Organisms can live in extremes of pressure, salinity,acidity and radiation. Organisms that live inextreme environments are known as extremophiles.

The presence of extremophiles on Earth indicatesthat life can exist on the icy planets and hot planets.Extremophiles have been found under thousands ofmeters of ice in Antarctica in conditions believed tobe similar to Jupiter’s moon Europa.

Extremophiles are common in hot ocean vents andit is believed that these bacteria may be the first lifeforms on Earth. Scientists believe that planetsundergoing volcanic activity in the presence of watercould foster similar life forms as those found onEarth near the hot ocean vents. Extremophiles havealso been found living in pockets of water severalkilometers below Earth’s surface. They usehydrogen gas to survive, formed by the splitting of water in the presence of uranium. Scientists believethat it is possible to find this kind of life form onMars since water and uranium are present on thisplanet.

Scientists hope to better understand the origin of lifeon Earth and how life might originate on otherplanets. They have been exploring places on Earththat resemble the conditions of early Earth when lifebegan. These environments include the ocean floor,the surface of hot volcanic springs and tidal pools. If the conditions that are believed to have producedlife on earth exist elsewhere in the universe, then lifemay exist elsewhere in the universe. Scientists arelooking for planets and moons that may havemolten cores and oceans. Sunlight is not alwaysconsidered essential since it is not necessary forchemical reactions (chemosynthesis) if geologicactivity is present.

The Search for Life Beyond Earth

Elements found on Earth exist throughout theuniverse. These elements are believed to have beenformed by exploding stars. Therefore, it isreasonable to assume that the carbon in our bodies,the iron in our blood, and the calcium in our bonescame from processes that took place in space.

As mentioned earlier, scientists haven beenexploring the universe for evidence of life by lookingfor three main components that could support life:an energy source, water and organic molecules. Organic molecules have been found on otherplanets. Comets have been shown to contain waterand organic matter. Volcanoes on Earth and otherplanets can provide energy for life, as well as watervapour and organic compounds. The icy surfaces ofmoons and planets also suggests that liquid watercould have existed or presently exists to sustain life.

Life from Earth has been shown to survive under theconditions of the moon. Bacteria that were accidentlytransported to the moon by a spacecraft survived onthe moon. This suggests that if life from Earth couldsurvive on the moon, then perhaps it could haveevolved and survived elsewhere in the universe.

The habitable zone in our solar system is the region inwhich scientists believe life may be supported. It wasonce believed to be between the planets of Venus andMars. This is because they are close enough to theSun for the solar energy to drive chemical reactionsbut not so close that the energy of the Sun woulddestroy organic molecules or evaporate water from thesurface of these planets. Scientists have expanded thehabitable zone since the gravitational pull of largerplanets can create enough energy to heat the cores oforbiting moons. As a result, there are several planetsand moons that could be habitable.

Venus: Numerousspace missions havebeen sent over theyears to Venus fromthe US and theformer Soviet Union. The Venera probesfrom the Soviets in1966 to 1982 foundthat Venus was dryand hot with verylittle oxygen. Theheat was so intensethat the probes were destroyed after a half hour ofcollecting data. It is believed that Venus was moretemperate at one time but that some kind ofcatastrophe created a greenhouse effect that trappedheat within the atmosphere. Venus’s terrain consists

APPENDIX C


of gently rolling plains with some broad depressionsand low rising mountains. Much of Venus iscovered by lava flows and some active volcanoes stillexist. It is believed that Venus once had largeamounts of water. Now, rain falls as carbon dioxideand sulfur. The atmosphere is made up of mainlycarbon dioxide and thick layers of sulfuric acid.Lightning strikes at a rate of more that 10 times persecond. There are low amounts of water vapor andoxygen. Mars: There have been numerous expeditions toMars in search of life. NASA Viking probes in 1976examined soil from the surface of Mars to look forsigns of life. No life was found but some chemicalreactions were evident in the soil. Dry river bedswere also found to indicate that there was oncewater on the surface. This means that theatmosphere was more dense at one time and mayhave supported life. Polar ice caps on Mars grow andrecede with the seasons. The landscape of Marsconsists of plains, canyons, mountains, volcanoes,craters and dry river beds. There is presently a thinatmosphere composed of carbon dioxide, nitrogen,argon and small amounts of oxygen and water. It isbelieved that a catastrophic event must haveoccurred about 3.5 billion years ago. Theatmosphere thinned out and the ozone layer thatmay have existed collapsed. The planet was exposedto harmful UV rays and the river beds eitherevaporated or froze into the ground. Mars meteorites found in Antarctica may containpossible fossils. This has created serious debateamong scientists. Some believe that life once existedon Mars and that we may one day find a rich fossil.

Europa: Europa is one of the moons that orbitJupiter. Scientists are considering the possibilitythat life may exist on Europa because they havefound evidence to support the existence of oceansbeneath its icy surface. The Galileo space probefound the icy landscape was fractured and suggeststhat something must be constantly fracturing andreplacing the ice such as an ocean beneath. The lackof craters also indicates that the icy surface mustconstantly be replaced. Scientists are speculatingthat life could exist in this ocean. The ocean may bewarmed by Europa’s molten core and may containdeep sea vents that support life similar to Earth. The surface of Europa is relatively smooth with very

few craters. The gravitational pull of Jupiter couldcreate enough heat to maintain liquid waterunderneath Europa’a icy surface. The atmosphere iscomposed solely of oxygen. It is believed that thisoxygen is not produced biologically.

Titan: Titan is Saturn’s largest moon and ischaracterized by an impenetrably dense, thick,clouded atmosphere. Its lower atmosphere iscomposed primarily of nitrogen, with low amountsof argon and methane. Its upper atmospherecontains high amounts of methane formed from thetrace amounts of organic compounds, known asliquid hydrocarbon, in the lower atmosphere. It isbelieved that there are large lakes on the surface ofTitan containing these liquid hydrocarbons and thatthese conditions are similar to those of theprimordial Earth when terrestrial life originated. Pictures from the Hubble telescope indicate thatthere may be land masses similar to continents. Probes should reach Titan in 2004 to determine theaccuracy of these pictures. In 1979, the Pioneer 11spacecraft determined that the temperature was toocold to support life. Since then the discovery ofextremophiles on Earth suggest that this may not bethe case.

In 1998, the European Space Agency's InfraredSpace Observatory (ISO) discovered water vapor inthe atmosphere ofTitan. The distancefrom the sun wouldindicate that thesurface would betoo cold to supportliquid water butscientists speculatethat it is possiblethat comets orasteroids strikingthe surface could maintain water in its liquid statefor up to 1000 years.

Tagish Lake Meteorite: Fragments of a meteoritefell to Earth in 1999 in Tagish Lake of the Yukonterritory. These fragments contained organic blobssimilar to those created in laboratories attempting tosimulate life. It is possible that Earth was providedwith these organic globules from meteoritesthroughout history, including when life first began

APPENDIX C


to form. This meteorite originated from the outerasteroid belt and could have easily landed on Jupiterand Europa. This discovery has added to the debateover the Panspermia theory.

Conclusion

Many scientists believe that intelligent life forms donot exist beyond Earth. More scientists are likely toagree that microscopic life is common in our galaxy. However, many feel that our search among the starsfor signs of life is much like the voyage ofColumbus. We will never know whether life existselsewhere unless we continue our exploration of theuniverse. “...Our mission is to explore strange newworlds; to seek out new life and new civilizations; toboldly go where no man has gone before...”

References

Astrobiology101:Exploring the Living Universe. Available at:www.astrobiology.com/adastra/astrobiology101.html. Bullard, Chetty et al. (2003). Biology. McGraw-Hill Ryerson. Toronto

Cambell, Michell and Reece. (2000). Biology:Concepts and Connections, 3rd ed. Addison WesleyLongman, Inc. Don Mills, Ontrario.

Clarke, Tom. (2002). Goldmine yeilds clues forLifeon Mars. Available at:www.nature.com/nsu_pf/021209.021209-1.html.

Life Beyond Earth. A Film by Timothy Ferris. PBSDVD Video. A production of KCTS/SEATTLEwith LARK INTERNATIONAL in association withPBS and DEVILLIER DONEGANENTERPRISES.

Http://science.nasa.gov/newhome/headlines/astO/sep98-1.htm

Life Beyond Earth. Available at:www.pbs.org/lifebeyondearth/

Stenger, Richard (2002). Meteorite ‘ready-madehome’ for life. Available at:http://www.cnn.com/2002/TECH/space/12/24/tagish.meteorite/index.html

Questions

Understanding Concepts1 Discuss the significance of the work done by

Haldane, Oparin, Miller, and Urey regardingthe beginning of life on Earth.

2. What features are scientists exploring on otherplanets that may lead to the formation andexistence of life?

3. What types of evidence have been found byscientists to suggest life can exist beyond Earth?

4. Describe five types of extremophiles found onEarth. Explain why scientists believe they maybe found elsewhere in the universe.

5. What evidence suggests that life could exist onVenus, Mars, Europa, and Titan?

Extensions:1. Enter the following website:

www.pbs.org/lifebeyondearth/resources/teacher.html. Do the activity entiltled AlienCreatures: Extra terrestrial and TerrestrialOddities. Use what you know about evolutionand adaptation to create your own alien creaturesuited to live according to the conditions onanother planet.

2. Enter the following website:www.pbs.org/lifebeyondearth/resources/teacher.html. Do the activity entiltled TheHabitable Zone: A Europa Probe. Design aprobe to travel to Europa that would have toconsider the conditions of the planet. Thisprobe would search for signs of life whichmeans that you would have to consider how toidentify life outside of Earth.

3. Determine the signs of life that researchersshould be exploring when looking for lifebeyond Earth. Consider if these signs of lifeshould be the same as organisms on Earth.

APPENDIX C


4. Enter the following website:www.pbs.org/lifebeyondearth/listening/drake.html. Use the Drake Equation to calculatethe possibility that life exists beyond Earth. Discuss how you feel about the accuracy of thisformula.

5. Cassini Saturn Orbiter and Huygens Titan Probereached Titan in the summer of 2004. Researchtheir findings and explore if these results couldsupport the existence of life on Titan.

6. Debate whether or not you feel life could existbeyond Earth.

Documents

3201 Appendix C 151-182 Stse - Newfoundland And · APPENDIX C 152 BIOLOGY 3201 CURRICULUM GUIDE Important Note These STSE modules are intended for teacher reference. Each is designed