Review for PAP Bio 11 Final Exam

Biological Molecules

1. Describe the distinguishing characteristics of carbohydrates, and explain the biologically important function of this group.

2. Describe how carbohydrates are classified.

3. Describe the characteristics of each class of carbohydrates.

4. Draw a few of the main carbohydrate molecules and state the differences between them (eg glucose, fructose...etc)

5. Explain how the following relate to the synthesis of various carbohydrates; hydrolysis and dehydration synthesis.

6. explain what distinguishes lipids from other major classes of macromolecules and explain the biologically important functions of this group.

7. What are the various classifications of lipids? Give examples for each classification.

8. Discuss characteristics/properties functions for each lipid category.

9. know the molecular structures for glycerol, fatty acids, triglyceride, phospholipid and steroid.

10. What is meant by saturated or unsaturated triclyceride?

11. How are triglycerides and phospholipids made?

12. Explain how dehydration synthesis and hydrolysis become involved in fat synthesis or fat breakdown.

13. Describe the characteristics that distinguish proteins from the other major classes of macromolecules, and explain the biologically important functions of this group.

14. What elements are unique to proteins?

15. List and recognize four major components of an amino acid and explain how amino acids may be grouped according to the physical and chemical properties of side chains.

16. illustrate the general structure of an amino acid.

17. Identify a peptide bond and explain how it is formed.

18. Describe primary, secondary, tertiary and quaternary structures in proteins. How is each formed? What type of bonding or chemical interactions occur in each and draw what they look like.

19. How do the properties of amino acids affect protein structure?

20. Explain how the following relate to proteins: dehydration synthesis and hydrolysis

21. What are nucleic acids? What are their functions?

22. What are the components of nucleic acids.

1. Carbohydrates are sugar molecules (chain or single) that are almost universally used as an intermediate energy source in living things. They play a structural role in some organisms.

2. Carbohydrates are classified based on the number of monosaccharides it contains. 2 monosaccharides mean that it’s a disaccharide, and many monosaccharides indicate that it is a polysaccharide.

3.Monosaccharides – a single sugar molecule; provide ready energy

Disaccharides – 2 monosaccharides made by the dehydration reaction; has varied uses

Polysaccharides – polymers of monosaccharides; are energy storage molecules

4. Glucose:

It is a 6 carbon molecule and is broken down in almost all types of organisms during cellular respiration for the creation of ATP molecules.

Sucrose:

Sucrose is a disaccharide that is created from joining glucose and fructose during a dehydration reaction. It is the sugar that we regularly use to sweeten our food and is a form of sugar that is transported in plants.

5. During the dehydration of 2 or more monosaccharides, a disaccharide or polysaccharide can be formed along with water. A hydrolysis reaction, it reverses this process and so the disaccharide or polysaccharide breaks up into monosaccharides.

6. Lipids are organic compounds that are insoluble and are usually used for insulation or energy storage. They also possess hydrocarbon chains.

7. Triglycerides: butter, corn oil

Phospholipids: phospholipid bilayer in the plasma membrane

Steroids: cholesterol

Waxes: candle

8. Triglycerides: fatty chain and glycerol. Each fatty chain is a long hydrocarbon chain with a carboxyl group attached to the end; used for long-term energy storage and insulation

Phospholipids: contains a phosphate group and a double bond in the tail; makes up the plasma membrane

Steroids: skeletons of 4 fused carbon rings and differs due to the functional group attached; component of the plasma membrane and sex hormones

Waxes: long-chain fatty acids bond with long-chain alcohol chain; provides protection and prevents water loss

9. Glycerol:

A compound that contain 3 –OH groups. It is soluble in water since the –OH groups are polar.

Triglycerides:

Formed by a dehydration reaction with 3 fatty acids and a glycerol. Does not mix with water.

Fatty acids:

A hydrocarbon chain that contains a –COOH group. Can be saturated or unsaturated depending on the presence of double bonds.

Phospholipids:

2 hydrocarbon chains (fatty acids) attached to a glycerol along with a polar phosphate group with a double bond kink in one of its tails.

Steroids: (Cholesterol)

4 fused carbon rings. Steroids differ from one another based on the functional group attached.

10. Saturated triglyceride: hydrocarbon chains with only single bonds; results in a solid

Unsaturated triglyceride: hydrocarbon chains with at least one double bond; results in a liquid

11. Triglycerides are made when a dehydration reaction causes 3 fatty acids to react to the –OH groups attached to glycerol and eventually forms triglyceride and 3 water molecules.

Phospholipids are created by having 2 fatty acids attached to glycerol. The third fatty acid chain is replaced by a phosphate group and there is a double bond in one of its tails, making it kink.

12. Like mentioned before, the dehydration reaction forms triglyceride by removing water molecules and joining the glycerol with the 3 fatty acids together. Phospholipids are made also in the same way but instead of having the third fatty acid chain, it is substituted by a phosphate group instead. When hydrolysis happens, water is added to break down the fat molecules.

13. Proteins are important for the structure and functions of cells. They can help support, metabolize, transport, defend, regulate and move.

14. Nitrogen

15. An amino acid has a central carbon atom that’s attached to a hydrogen and three other groups of atoms (one is an R group). It contains an amino group ( –NH2), an acid group ( –COOH) and an R group, which represents the remainder of the molecule. Due to the variations that can result from the R group, the amino acids can have different levels of structures and shape per protein. R groups can be hydrophobic, hydrophilic, or ionized.

16.

17. When 2 amino acids join due to the dehydration reaction, the covalent bond that joins the two is called the peptide bond. It’s the joint between the 2 amino acids.

18. Primary:

A polypeptide containing a sequence of amino acids that are held together by peptide bonds. All proteins have this structure.

Secondary:

Occurs when polypeptide coils or folds in a certain way due to hydrogen bonding. The alpha helix is formed from hydrogen bonding at every fourth amino acid, and beta sheet is created when the polypeptide turns back on itself and hydrogen bonding occur.

Tertiary:

Results from the hydrogen bonds, ionic bonds, and covalent bonds between the R groups in the polypeptide to give it a 3D globular shape.

Quaternary:

This takes place when at least 2 polypeptides joins to form a protein.

19. The different sequence of amino acids in a protein leads to a certain level of structure and particular shape in the protein. The R group that’s attached to the amino group also plays a role in this.

20. The dehydration reaction synthesizes 2 amino acids together and can eventually form a chain bonded by peptide bonds, and lead to the creation of proteins with various structures and shapes. Hydrolysis can undo the bonding of amino acids.

21. Nucleic acids are polymers of nucleotides and have specific functions in cells. In DNA, it stores genetic information for replication and amino acid sequence to make protein. RNA can take part in protein synthesis but using information obtained from DNA.

22. Nucleic acids are made from nucleotides which contain a phosphate, a pentose sugar, and a nitrogen-containing base (adenine, cytosine, thymine, uracil, guanine) There are 4 different types of nucleotides for DNA and RNA, and when they join in a certain sequence during dehydration reactions, nucleic acids are formed.

Homeostasis

1. What is homeostasis?

2. Describe the two types of homeostasis and carefully describe one of each.

3. Describe how alteration of feedback often results in negative (deleterious) consequences (eg. diabetes mellitus)

4. Describe an example of how an operon in gene regulation could be an example of negative feedback.

Homeostasis is the maintenance of internal conditions in a cell or organism by means of selfregulating mechanisms that curtail fluctuations above and below a normal range.

1.The organ systems of the human body contribute to homeostasis.

a.The respiratory system adds oxygen and removes carbon dioxide; the amounts are altered to meet needs.

b.The liver removes and stores glucose as glycogen and then replaces the blood glucose levels when they lower.

c.The hormone insulin is secreted by the pancreas to regulate glucose levels.

d.The kidneys are under hormonal control to excrete wastes and salts and to maintain blood pH.

2.Although homeostasis is controlled by hormones, it is ultimately controlled by the nervous system.

3.The brain contains centers that regulate temperature and blood pressure.

4.Regulation requires a receptor that detects unacceptable levels and signals a regulator center that can direct an adaptive response; once normalcy is obtained, the receptor is no longer stimulated.

A. Negative Feedback

1. A negative feedback mechanism involves a response in which a variable is kept close to a particular set point.

a. The process involves a sensor and a control center.

b. The sensor detects a change in the internal environment.

c. The control center brings about an effect to bring conditions back to normal.

d. Example: When blood pressure rises, sensory receptors signal a control ceneter in the brain. This center stops sending nerve impulses to the arterial walls and the relax. Once the blood pressure drops, signals no longer go to the control center.

e. A home heating system is a mechanical example of a negative feedback mechanism.

f. Human Example: Regulation of Body Temperature

1) The sensor and control center are located in the hypothalamus.

2) When body temperature is above normal, the control center directs blood vessels in the skin to dilate—heat is lost to the environment.

3) When body temperature is below normal, the the control center directs blood vessels in the skin to constrict—heat is conserved in the body.

B. Positive Feedback

1. A positive feedback mechanism involves output that intensifies and increases the input, thereby increasing the process; an ever-greater change in the same direction occurs.

2. Once childbirth begins, each event amplifies; the process continues until birth occurs.

3. Positive feedback mechanisms can be harmful, e.g., when a fever causes metobolic changes that push the fever even higher.

4. Diabetes mellitus occurs when the body cells can’t absorb as much glucose as they can and so it is excrete in urine from the rising blood glucose. Normally when glucose levels are high, the pancreas would secrete insulin into the blood to stimulate the uptake of glucose in liver, muscle cells, and adipose tissues. The liver would store the glucose as glycogen, the muscle cells would store glycogen to make proteins, and the adipose tissue would use glucose to form fat, leading to a decrease in the blood glucose level.

Cell Communication

1. Describe the use of chemical messengers over short distances (by using local regulators) .Microbes use them to communicate with nearby cells to regulate specific pathways in response to population density (quorum sensing; see Bozeman video)

2. Describe the signal transduction pathway that coordinate activities within individual cells that support the function of the organism as a whole (epinephrine stimulation of glycogen breakdown in animals)

3. Describe the APC’s (antigen presenting cells) of the immune system and how they interact by cell to cell contact

4. Choose 2 examples (human growth hormone, thyroid hormone, testosterone or estrogen or insulin) and describe how the endocrine system has signals that are released by one cell and can travel long distances to target cells of another cell type.

4. 13.1 Prokaryotic Regulation

1.Bacteria do not require the same enzymes all the time; they produce just those needed at the moment.

2.Francois Jacob and Jacques Monod (1961) proposed the operon model to explain regulation of gene expression in prokaryotes.

a.In the operon model, several genes code for an enzyme in the same metabolic pathway and are located in a sequence on a chromosome; expression of structural genes is controlled by the same regulatory genes.

b.An operon is a group of structural and regulatory genes that function as a single unit; it includes the following:

1)A regulator gene, located outside the operon, codes for a repressor protein molecule that controls whether the operon is active or not.

2)A promotor is the sequence of DNA where RNA polymerase attaches when a gene is to be transcribed.

3)An operator is a short sequence of DNA where an active repressor binds, preventing RNA polymerase from attaching to the promotor--transcription therefore does not occur.

4)Structural genes are one to several genes coding for enzymes of a metabolic pathway that are transcribed as a unit.

A.The trp Operon

1.Some operons in E. coli usually exist in the “on” rather than the “off” condition.

2.E. coli produces five enzymes as part of the anabolic pathway to synthesize the amino acid tryptophan.

3.If tryptophan is already present in medium, these enzymes are not needed and the operon is turned off .

a.The regulator codes for a repressor that usually is unable to attach to the operator.

b.The repressor has a binding site for tryptophan (if tryptophan is present, it binds to the repressor).

c.This changes the shape of the repressor that now binds to the operator.

4.The entire unit is called a repressible operon; tryptophan is the corepressor.

5.Repressible operons are involved in anabolic pathways that synthesize substances needed by cells.

B. The lac Operon

1.If E. coli is denied glucose and given lactose instead, it makes three enzymes to metabolize the lactose.

2.These three enzymes are encoded by three genes.

a.One gene codes for beta-galactosidase that breaks lactose to glucose and galactose.

b.A second gene codes for a permease that facilitates entry of lactose into the cell.

c.A third gene codes for enzyme transacetylase, which is an accessory in lactose metabolism.

3. The three genes are adjacent on a chromosome and under control of one promoter and one operator.

4.The regulator gene codes for a lac operon repressor protein that binds to the operator and prevents transcription of the three genes.

5.When E. coli is switched to medium containing an allolactose, this lactose binds to the repressor and the repressor undergoes a change in shape that prevents it from binding to the operator.

6.Because the repressor is unable to bind to the operator, the promoter is able to bind to RNA polymerase, which carries out transcription and produces the three enzymes.

7. An inducer is any substance (lactose in the case of the lac operon) that can bind to a particular repressor protein, preventing the repressor from binding to a particular operator; consequently, RNA polymerase can bind to the promoter and transcribe the structural genes.

C.Further Control of the lac Operon

1.Since E. coli prefers to break down glucose, how does E. coli know how to turn on when glucose is absent?

2.When glucose is absent, cyclic AMP (cAMP) accumulates; cAMP has only one phosphate group and attaches to ribose at two locations.

a.CAP is a catabolite activator protein (CAP) in the cytoplasm.

b.When cAMP binds to CAP, the complex attaches to a CAP binding site next to the lac promoter.

c.When CAP binds to DNA, DNA bends, exposing the promoter to RNA polymerase.

d.Only then does RNA polymerase bind to the promoter; this allows expression of the lac operon structural genes.

3.When glucose is present, there is little cAMP in the cell.

a.CAP is inactive and the lactose operon does not function maximally.

b.CAP affects other operons when glucose is absent.

c.This encourages metabolism of lactose and provides a backup system for when glucose is absent.

4. Active repressors shut down the activity of an operon—this is negative control..

5. CAP is an example of positive control; when the molecule is active, it promotes the activity of the operon.

6. Use of both positive and negative controls allows the cell to fine-tune control of its metabolism.

If both glucose and lactose are present, the cell preferentially metabolizes glucose

1

Please note that you are also responsible for knowing about : Eukaryotic Regulation

1.Different cells in the human body turn on different genes that code for different protein products.

2.Eukaryotes have four levels of regulatory mechanisms to control gene expression; two in the nucleus and two in the cytoplasm.

3. There are several levels of control that can modify the amount of gene product.

a. Chromatin structure: if genes are not accessible to RNA polymerase, they cannot be transcribed.

1) Chromatin structure is part of epigenetic inheritance, the transmission of genetic information outside the coding sequences of a gene.

b. Transcriptional control in the nucleus determines which structural genes are transcribed and the rate of transcription; it includes transcription factors initiating transcription and transposons (DNA sequences that move between chromosomes and shut down genes).

c. Posttranscriptional control occurs in the nucleus after DNA is transcribed and preliminary mRNA forms.

1)This may involve differential processing of mRNA before it leaves the nucleus.

2)The speed that mature mRNA leaves nucleus affects the ultimate amount of gene product.

d. Translational control occurs in cytoplasm after mRNA leaves the nucleus but before there is a protein product.

1)The life expectancy of mRNA molecules can vary, as well as their ability to bind ribosomes.

2)Some mRNAs may need additional changes before they are translated at all.

e. Posttranslational control occurs in the cytoplasm after protein synthesis.

1)Polypeptide products may undergo additional changes before they are biologically functional.

2)A functional enzyme is subject to feedback control; binding of an end product can change the shape of an enzyme so it no longer carries out its reaction.

Cell Communication

1. Describe the use of chemical messengers over short distances (by using local regulators) .Microbes use them to communicate with nearby cells to regulate specific pathways in response to population density (quorum sensing; see Bozeman video)

2. Describe the signal transduction pathway that coordinate activities within individual cells that support the function of the organism as a whole (epinephrine stimulation of glycogen breakdown in animals)

3. Describe the APC’s (antigen presenting cells) of the immune system and how they interact by cell to cell contact

4. Choose 2 examples (human growth hormone, thyroid hormone, testosterone or estrogen or insulin) and describe how the endocrine system has signals that are released by one cell and can travel long distances to target cells of another cell type.

1. A) Over Short distances: Local regulators affect neighbouring cells. An example is prostaglandins which promotes pain and inflammation. Quorum sensing in bacteria is useful for bringing about a response when a certain number of individuals is achieved

B) An axon branches off into axon terminals which have a gap called the synapse. Because the nerve impulse cannot just pass through here, neurotransmitters must be used to get the transmission across to the other side. Ca+ causes synaptic vesicles to enclose neurotransmitters and release them into the synaptic cleft where they will bind to a receptor and allow Na+ to diffuse to the other side. An action potential begins.

Quorum Sensing:

What is Quorum sensing and how do bacteria talk to each other?

The discovery that bacteria are able to communicate with each other changed our general perception of many single, simple organisms inhabiting our world. Instead of language, bacteria use signalling molecules which are released into the environment. As well as releasing the signalling molecules, bacteria are also able to measure the number (concentration) of the molecules within a population. Nowadays we use the term 'Quorum Sensing' (QS) to describe the phenomenon whereby the accumulation of signalling molecules enable a single cell to sense the number of bacteria (cell density). In the natural environment, there are many different bacteria living together which use various classes of signalling molecules. As they employ different languages they cannot necessarily talk to all other bacteria. Today, several quorum sensing systems are intensively studied in various organisms such as marine bacteria and several pathogenic bacteria.

Why do bacteria talk to each other?

1. QS enables bacteria to co-ordinate their behaviour. As environmental conditions often change rapidly, bacteria need to respond quickly in order to survive. These responses include adaptation to availability of nutrients, defence against other microorganisms which may compete for the same nutrients and the avoidance of toxic compounds potentially dangerous for the bacteria. It is very important for pathogenic bacteria during infection of a host (e.g. humans, other animals or plants) to co-ordinate their virulence in order to escape the immune response of the host in order to be able to establish a successful infection.

2.During a signal transduction pathway, a peptide hormone like epinephrine will bind to a receptor in the plasma membrane and lead to the activation of an enzyme that changes ATP to cAMP. cAMP then activates an enzyme cascade which would result in many molecules of glycogen being broken down into glucose.

A. The Action of Hormones

1. The Action of Peptide Hormones

a. The term peptide hormone is used to include hormones that are peptides, proteins, glycoproteins, and modified amino acids.

b. Epinephrine is a peptide hormone that binds to a receptor protein in the target cell’s plasma membrane; a relay system leads to conversion of ATP to cyclic AMP (cAMP).

c. Cyclic adenosine monophosphate (cAMP) is made from ATP; it has one phosphate group attached to adenosine at two locations.

d. Peptide hormones are the first messenger; cAMP and calcium are the second messenger.

e. The peptide hormone does not enter the cell; the second messenger sets an enzyme cascade in motion.

2. The Action of Steroid Hormones

a. Steroid hormones are lipids and cross cell membranes freely; they do not bind to plasma membrane receptors.

b. Inside the cytoplasm or a nucleus, steroid hormones (e.g., estrogen, progesterone) bind to a specific receptor.

c. The hormonereceptor complex binds to DNA, resulting in activation of genes (transcription) that produce enzymes (translation).

d. Steroids act more slowly than peptide hormones because it takes more time to synthesize new proteins than to activate enzymes already present in cells; however, their action lasts longer.

e. Steroid hormones are produced in the adrenal cortex, the ovaries, and the testes.

3. An antigen presenting cells (macrophage or dendritic cell) would display an antigen to a helper T cell to activate them, which would in turn, activate the B cells and killer T cells. T cells are unable to recognize antigens without the aid of APCs, unlike the B cells, so they need this information presented to them.

T cells are responsible for cell-mediated immunity.

a.Antigens must be presented to T cells by an antigen-presenting cell (APC).

b.T cells differentiate into either helper T cells, which release cytokines, or cytotoxic T cells, which attack and kill virus-infected cells and cancer cells.

4. Thyroid Hormone

Thyroid hormones do not have a target organ. Instead, they stimulate all the cells of the body to metabolize faster. It breaks down glucose faster so more energy is available. It also helps maintain normal blood Ca2+ by secreting calcitonin so that bones can take up Ca2+ to lower the level of it.

Human Growth Hormone

The hormone is produced in the anterior pituitary by stimulation from the hypothalamus. The anterior pituitary would secrete this hormone into the bloodstream where it can then be delivered to specific cells, tissues and glands.

Meiosis/Fertilization and Embryology

1. Where does meiosis occur in humans?

2. What is the purpose of meiosis? Describe what happens to chromosomes during meiosis.

3. What is fertilization and why is fertilization important to the species as a whole?

4. How do morphogens stimulate cell differentiation and development during embryology?

5. Describe how embryology changes a single cell to an differentiated embryo with different tissues in different places?

1. Meiosis occurs in the primary sex organs in humans (testes, ovaries).

2. The purpose of meiosis is to reduce the total number of chromosomes to half. First you start off with a diploid number of chromosomes. They go into homologous pairs and synapse before separating. Then they divide again and the end result is a haploid number of 4 new daughter cells.

3. Fertilization is when the gamete from the father enters the mother’s gamete to change it into a zygote. Fertilization is important because it restores the total number of chromosome back into the organism, making them diploid again.

4. If there is a mutation in the bicoid protein which is mostly concentrated in the anterior, it can result in an embryo with two posterior ends. It also prevents the formation of the posterior region. The nanos protein is required for abdomen formation so a mutation will result in no abdomen.

5In the beginning, the embryo has no organs and only tissues. The amniotic cavity is right above the embryo and the yolk sac is below. The chorion develops villi, which is a very important structure for the mother and child as it also for exchange. The allantois and yolk sac form the umbilical cord, and after about a month, the embryo has a head region and a tail region. The embryo then develops more and starts to look more human.

A. Embryonic Development

1. Cellular Stages of Development

a. Development is all of the changes that occur during the life cycle of an organism.

b. An organism is an embryo during the first stages of development.

c. After fertilization, a zygote undergoes cleavage, cell division without growth.

d. DNA replication and mitosis occur repeatedly, and the cells get smaller with each division.

e. In the lancelet, the cell divisions are equal in the resulting morula.

f. A cavity called the blastocoel develops forming a hollow ball called the blastula.

2. Tissue Stages of Development

a. The tissue stages of development are early gastrula and late gastrula.

b. The early gastrula stage begins with the invagination of certain cells into the blastocoel to form two of the three primary germ layers.

c. The outer layer of cells becomes ectoderm; ectoderm gives rise to the epidermis of the skin, the epithelial lining of the mouth and rectum, and the nervous system.

d. The inner layer of cells becomes the endoderm that gives rise to the epithelial lining of the digestive tract and the respiratory tract, associated glands of the digestive and respiratory system, and the lining of the urinary bladder; a pore created by invagination is the blastopore.

e. The late gastrula has, in addition to ectoderm and endoderm, a middle layer of cells called the mesoderm.

1)The outpocketings grow and fuse, forming a two layered mesoderm.

2)The space between them is the coelom that contains the body organs.

3)The mesoderm gives rise to the skeleton, the dermis of the skin, the skeletal system, the muscular system, the excretory system, the reproductive system (including most epithelial linings), and the outer layers of respiratory and digestive systems.

f. These germ layers then develop into those future organs.

3. Organ Stages of Development

a. The newly formed mesoderm cells along the main axis coalesce to form a dorsal notochord; it persists in lancelets but is replaced in frogs, chicks, and humans by the vertebral column.

b. The nervous system develops from the midline ectoderm located just above the notochord.

1) At first, the cells on the dorsal surface of the embryo thicken, forming the neural plate.

2) Then neural folds develop on either side of a neural groove which becomes the neural tube when the folds fuse.

3) At this point the embryo is called a neurula.

4) Later, the anterior end of the neural tube develops into the brain; the rest becomes the spinal cord.

c. Midline mesoderm cells that did not contribute to the formation of the notochord now become two longitudinal masses of tissue.

1) The two tissue masses become blocked off into somites.

2) The somites give rise to segmental muscles in all chordates; in vertebrates the somites also form the vertebral bones.

Digestive System

(See CHART on Enzymes GIVEN IN CLASS)

1. Mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus, salivary glands, liver, gallbladder, and pancreas.

2. The mouth begins mechanical digestion of food and is aided by the salivary glands which secrete amylase to break down starch. Once the food is chewed up into a bolus, it goes down the esophagus and into the stomach where further chemical digestion takes place. The digested food goes into the small intestine from reabsorption of nutrients as it passes through to the large intestine. It then heads out to the rectum and leaves the body by the anus. The liver produces bile for the emulsification of fats while the gallbladder stores bile from the liver to send it to the small intestine. The pancreas creates pancreatic juice to help with the chemical digestion and also sends that to the small intestine.

3. Salivary amylase breaks down starch into maltose and is found in the mouth. Pancreatic amylase in the small intestine also breaks down starch into maltose. Finally, maltase turns maltose into glucose. Pepsin in the stomach dissolves protein into peptides. Trypsin also turns proteins into peptides and it is located in the duodenum. Peptidase turns peptides into amino acids and it is in the intestine. Bile salts change fat into fat droplets which are then converted into a glycerol and 2 fatty acids by lipase.

(See CHART GIVEN IN CLASS)

Nervous System

1. Describe the structure of a neuron

2. describe how these structures allow for detection, generation and transmission and integration of chemical signals.

3. What are the gaps between Schwann cells called and why are they needed?

4. Explain the transmission of an action potential.

5. What is a neurotransmitter? Explain using an example.

6. What is the difference between a stimulatory and inhibitory response?

7. Describe how human brains organized to have different functions in different places.

8. What is a reflex arc?

1. Cell body – contains a nucleus and variety of organelles

Dendrites – short, highly branched processes that receive signals from the sensory receptors or other neurons and transmit them to the cell body

Axon – part of neuron that carries information to another neuron or other cells.

a. Motor (efferent) neurons have many dendrites and a single axon; they conduct impulses from the CNS to muscles or glands.

b. Sensory (afferent) neurons are unipolar; they conduct impulses from the periphery toward the CNS.

1) The process that extends from the cell body divides into two processes, one going to the CNS and one to periphery.

c. Interneurons (association neurons) are multipolar

1) They have highly-branched dendrites within the CNS.

2) Interneurons convey messages between the various parts of the CNS.

3) They form complex brain pathways accounting for thinking, memory, language, etc.

2. The axon allow for transmission when an action potential arrives at an axon terminal. Dendrites allow for synaptic integration. Neurons like the sensory neuron can detect pain and interneurons can generate complex pathways in the brain for processes like thinking, memory, and language.

9. The gaps are called nodes of Ranvier. They are needed because it’s more efficient than going through the whole axon since you get to jump gaps. This is called saltatory

Above we see a myelinated neuron.  If the myelinated cells are wrapped around interneurons, they are oligodendrocytes. If they’re wrapped around neurons in the PNS they’re called Schwaan cells. In either case there are these gaps called Nodes of Ranvier.  The only place these potassium or sodium ions can enter or leave are from these spaces that are unmyelinated.  Sodiums come in and potassiums going out just like a an unmymelinated nerve fiber, except this signal seems to jump from one node to the next. This is called saltatory conduction. It has nothing to do with salt but it comes from the latin word saltaire which means to jump or leap.

Due to this skipping, saltatory conduction is up to 50 times faster than conduction through the fastest unmyelinated axons because they don’t have to travel throughout every single space before moving to the next.

So in essence, the action potential is generated only at the nodes.  The cell membrane below the myelin sheaths hardly have any sodium channels and are therefore not excitable anyway.  Since the ionic currents are restricted to the nodes of Ranvier in the myelinated axons, this minimizes disturbances in the Na+/K+ concentration gradients which reduces the energy costs of the Na+/K+-ATP pump that have to restore ionic balance.

10. When action potential begins, depolarization occurs to permit Na+ to move to the inside of the axon. The action potential would end and repolarization would take place to allow K+ to go to the opposite side.

5. A neurotransmitter is a molecule that’s used to carry out a transmission across a synapse. You can think of a neurotransmitter as a boat that you use to carry your things across the lake to the other side.

6. An excitatory response creates a potential change that drives the neuron closer to an action potential. An inhibitory response does the opposite.

7. There are different lobes on the brain that controls for different functions. The occipital lobe is where all the visual-related things are located. The parietal lobe is associated with senses along with the temporal lobe. The frontal lobe is responsible for the movement of the body.

8. A reflex arc is when sensory receptors generate nerve impulses that move along sensory axons through a dorsal root ganglion toward the spinal cord. Interneurons integrate data from the sensory neurons and then relay signals to motor axons. They will then convey nerve impulses from the spinal cord to the skeletal muscle, which will contract. And the movement of the hand away from the pin is a response to the stimulus.

IMMUNITY

1. Name the non-specific immune responses.

2. Mammals have non-specific immune responses triggered by agents that disrupt normal homeostasis.

a)Explain the cell-mediated response of the cytotoxic T cells

a) Explain the humoral response of B cells

3. How are antigens recognized?

4. What produces antibodies and why are they essential?

5. What happens after a second exposure to an antigen?

1. Immunity is the ability to repel infectious agents, foreign cells, and cancer cells.

1.Immunity begins with nonspecific defenses.

2.The four nonspecific defenses include barrier to entry, protective proteins, natural killer cels, and inflammatory response.

A.Barriers to Entry

Skin and the mucous membranes lining the respiratory, digestive, and urinary tracts are non-chemical, mechanical barriers.

Ciliated cells lining the upper respiratory tract sweep mucous and particles up into the throat to be swallowed.

Oil gland secretions inhibit the growth of bacteria on the skin.

The stomach has a low pH (1.2–3.0) that inhibits the growth of many bacteria.

B. Inflammatory Response

1. If tissue is damaged, a series of events known as the inflammatory response, occurs.

2. The inflamed area has four symptoms: redness, pain, swelling, and heat.

3. Chemical signals, e.g. histamine, and mast cells, a type of white blood cell, cause vasodilation and increased permeability of capillaries.

4. Enlarged capillaries produce redness and a local increase in temperature.

5. The swollen area stimulates free nerve endings, causing pain.

6. Neutrophils and monocytes migrate by amoeboid movement to the site of the injury; they escape from the blood by squeezing through the capillary wall.

7. Dendritic cells and macrophages recognize the presence of pathogens and respond by releasing cytokines.

8. The cytokines stimulate other immune cells.

9. Neutrophils, dendritic cells, and macrophages engulf pathogens.

10. As phagocytic cells die, they, along with dead bacteria, dead tissue cells, and living white blood cells, form pus.

11. Dendritic cells and macrophages move to the lymph nodes and spleen, where they activate B and T lymphocytes.

12. An inflammatory response may also involve the production of a fever, which serves to inhibit the growth of microorganisms and stimulates immune cells.

C.Phagocytes and Natural Killer Cells

1. Neutrophils are cells that are able to leave the bloodstream and phagocyatize (engulf) bacteria in connective tissue.

2.Eosinophils are phagocytic, but are better known for attacking animal parasites that are too large to be phagocytized.

3.Macrophages and dendritic cells are the most powerful phagocytic white blood cells that engulf pathogens.

4. Natural killer (NK) cells kill virus-infected cells and tumor cells by cell-to-cell contact.

a. After stimulation by dendritic cells, they look for a self protein on the body’s cells.

b. NK cells are not specific; they have no memory and their numbers do not increase after stimulation.

D.Protective Proteins

1. Complement is composed of a number of plasma proteins designated by the letter C and a subscript.

2. It “complements” certain immune responses, which accounts for its name.

3. It amplifies an inflammatory reaction by binding to mast cells and triggering histamine release and by attracting phagocytic cells to the site of infection.

4. Some complement proteins binds to antibodies already on the surface of pathogens, thereby increasing the probability that pathogens will be phagocytized by a neutrophil or macrophage.

5. Some complement proteins form a membrane attack complex that produces holes in bacterial cell walls and plasma membranes; fluids and salts then enter to the point where the cell bursts.

6. Interferons are cytokines, proteins produced by virusinfected animal cells.

2. Specific Defense Against Disease

1. If nonspecific defenses fail to prevent an infection, specific defenses activate against a specific antigen.

2. We do not ordinarily become immune to our own cells; the immune system can tell “self” from “nonself.”

3. The steps to accomplish a specific defense are:

a.The immune system is able to recognize particular molecules, called antigens.

1) An antigen is called a foreign antigen because the body does not produce them; a self-antigen is an antigen that the body produces.

b.After recognizing antigens, the immune system can respond to them.

c.The immune system can remember antigens it has met before.

4. Specific immunity is primarily the result of the action of B lymphocytes (B cells) and T lymphocytes (T cells).

a. B cells and T cells recognize antigens because they have antigen receptors—plasma membrane proteins that allow them to combine with particular antigens.

b. B cells give rise to plasma cells that produce antibodies.

c. T cells differentiate into helper T cells, which regulate the immune response, or cytotoxic T cells, which kill virus-infected and tumor cells.

5. B cells are responsible for antibody-mediated immunity.

a. Each type of B cell carries its specific receptor on its surface; this is called the B cell receptor (BCR).

b. When a B cell in a lymph node of the spleen encounters an appropriate antigen, it is activated to divide.

The resulting cells are plasma cells, mature B cells that produce antibodies in the lymph nodes and spleen; the antibodies are identical to the BCR of the B cell that produced them.

3. The pathogens have different proteins on their surface and To recognize and fight the wide range of pathogens an individual will encounter, the lymphocytes of the adaptive immune system have evolved to recognize a great variety of different antigens from bacteria, viruses, and other disease-causing organisms. The antigen-recognition molecules of B cells are the immunoglobulins, or Ig. These proteins are produced by B cells in a vast range of antigen specificities, each B cell producing immunoglobulin of a single specificity (see Sections 1-8 to 1-10). Membrane-bound immunoglobulin on the B-cell surface serves as the cell's receptor for antigen, and is known as the B-cell receptor (BCR). Immunoglobulin of the same antigen specificity is secreted as antibody by terminally differentiated B cells—the plasma cells. The secretion of antibodies, which bind pathogens or their toxic products in the extracellular spaces of the body, is the main effector function of B cells in adaptive immunity.

4. Plasma cells produces antibodies and they are essential because antibodies help eliminate antigens.

5. The antigen is killed a lot faster than the first time.

Circulatory System and Respiratory System

Circulatory System and Respiratory system

1. Describe the structures and functions of the respiratory system

2. Describe the structures and functions of the circulatory system

3. Describe how the specialization of organs contributes to the overall functioning of the organism (eg. exchange of gases or circulation of fluids or digestion and excretion of food)

4. Predict the effects of a change in a component of the biological system on the functionality of an organism. (eg Raised H+ levels or CO2)

1. Nostril and nasal cavity – entry of oxygen and exit of carbon dioxide

Pharynx – air passage

Trachea – entrance to lungs

Bronchus – split of trachea

Bronchiole – branches from bronchus, branches off to alveoli

Diaphragm – aids breathing

Lung – location of gas exchange

2. Heart –pumps blood

Veins and arteries – pathway of blood

Capillaries – nutrients and waste exchange

3. All the specializations of organs contribute to carry out a specific function and eventually create an organ system. Since there are different organs that does different activities, it can cover and meet all the basic needs in making an organism properly function.

4. There are chemoreceptors adjacent to the respiratory center in the medulla oblongata that are sensitive to the carbon dioxide content of the blood, and chemoreceptors in aorta and carotid arteries that are sensitive to both the carbon dioxide content and the pH of the blood. When the carbon dioxide concentration rises or when the pH lowers the respiratory center is stimulated and the breathing rate increases. It is interesting to observe that the oxygen content of the blood does not directly affect the activity of the respiratory center.