Unit 1: Chemistry of Life, Part II: Biochemistrymsdaley.weebly.com/uploads/8/7/2/0/8720335/biochem... · · 2016-09-20PACKET #2 Unit 1: Chemistry of Life, Part II: Biochemistry

Biology H Name ________________________________________

2016 - 2017 Date ________________Block ________________

PACKET #2

Unit 1: Chemistry of Life, Part II: Biochemistry

Reading: BSCS Text Chapter 1.6 – 1.10

Learning Objectives:

Topic 3: Organic Molecules

11. Differentiate between organic and inorganic compounds (1.6).12. List the 6 most common elements found in living things: CHNOPS/SPONCH (p. 25)13. Define and relate the terms macromolecule, polymer, monomer, and polymerization (class)14. Describe and relate the terms: biosynthesis (dehydration synthesis), and decomposition (hydrolysis)(2.7)15. Describe (and identify a diagram of) monosaccharide, disaccharide, and polysaccharide and discuss theirsignificance in organisms (1.7).16. Describe (and identify a diagram of) the structure and importance of lipids - including phospholipids andcholesterol (1.8)17. Explain the difference in structure between unsaturated and saturated lipids, and explain why eating one type isbetter for your health than eating the other (1.8)18. Identify the functional groups and R group of an amino acid.19. Describe the four levels of structure in proteins, including how polypeptides form (1.9)20. Explain that different classes of proteins regulate and carry out the essential functions of life (1.9).21. Describe the structure of nucleic acids (1.10)22. Describe the importance of nucleic acids (1.11- 1.12)

Topic 4: Ecology Connection

Vocabulary (Topic 3): Organic molecule

Hydrocarbon Macromolecule Polymer Monomer Polymerization Dehydration synthesis

Hydrolysis Carbohydrate Monosaccharide

Disaccharide Polysaccharide Starch Glycogen Cellulose Lipids Hydrophobic Hydrophilic Phospholipids Cholesterol Steroids Saturated fat

Unsaturated fat Glycerol Fatty acid Protein Amino acid Polypeptide Peptide bond Hormone Antibody Structural protein

Enzyme

Primary, secondary, tertiary structure

Nucleic acid ATP Double helix Purine Pyrimidine

23. Describe the ecological relationships that exist between sea lions, pollock, and herring.24. Using your understanding of biomolecules, explain why sea lions might survive better on herring on pollock.

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Topic 5: Evolution Connection E – 8 Describe the process of chemical evolution; how do scientists think organic molecules arose? E – 9 Compare and contrast the atmosphere of Early Earth with the atmosphere on Earth today. E – 10 Describe the “RNA World” hypothesis. What evidence supports this idea? E – 11 Describe the heterotroph hypothesis (Oparin-‐Haldane hypothesis), and explain how this hypothesis

may be supported by (1) The Miller-‐Urey experiments (2) meteors (3) polymerization on clay (4) hydrothermal vents (5) catalytic RNA

Biological Molecules

Biological MoleculesWhat are the building blocks of life?

Why?From the smallest single-celled organism to the tallest tree, all life depends on the properties and reactions of four classes of organic (carbon-based) compounds—carbohydrates, lipids, proteins, and nucleic acids. These organic molecules are the building blocks of all living things, and are responsible for most of the structure and functions of the body, including energy storage, insulation, growth, repair, communica-tion, and transfer of hereditary information. Simple organic molecules can be joined together to form all the essential biological molecules needed for life.

Model 1 – Molecules of Life

Carbohydrates (monosaccharides)

Glucose Galactose Fructose

Lipids

Glycerol Fatty acids Triglyceride (fat or oil)

Proteins (amino acids)

Alanine Cysteine Amine group

Nucleic acids (nucleotides)

O

OH

HH

H

OH

OH

H OH

H

OH

O

OH

HH

OH

H

OH

H OH

H

OH

O

OH

H

OH

OH

H

H

OH OH

C

C

C

H

H

OH

H OH

H

H OH

C

O

(CH 2)12CH3OH

C

O

(CH 2)7CH=CH(CH 2)7CH3OH C

CH

H

H OC

O

CH3

OCO(CH 2)7CH=CH(CH 2)7CH3

CH

H OC

CH3

O

C

O

(CH 2)14CH3OH

C

R

H

N C

O

OH

H

HC

H

N C

O

OH

H

H

CH2SH

C

CH3

H

N C

O

OH

H

H

Proteins (amino acids)

Alanine Cysteine

Variable Rside chain

Carboxylicacid group

Aminegroup

NO

O

OH

OH

OH

O

P N

NN

NH2

OH

Variable R side chain

Carboxylicacid group

Nitrogen base

Phosphate group

Sugar

2

POGIL™ Activities for High School Biology

1. Use Model 1 to show which atoms are present in each type of molecule by listing the symbol foreach atom included. Carbohydrate has been done for you.

a. Carbohydrate— C, H, O c. Amino acid—

b. Lipid— d. Nucleic acid—

2. Which type of molecule includes an example with a long-chain carbon backbone?

3. In the molecule referred to in the previous question, what is the dominant element attached tothe carbon backbone?

4. The fatty acid chain of the lipids is often referred to as a hydrocarbon chain. Discuss with yourgroup why the chain is given this name and write a one-sentence defi nition for a hydrocarbon.

5. Which molecule has a central carbon atom with four different components around it?

6. Which molecule has a sugar, nitrogenous base, and phosphate group?

7. Discuss with your group members some similarities among all four types of molecules. List asmany as you can.

8. What is the chemical formula of the fi rst carbohydrate molecule shown?

9. What three structural groups shown do all amino acids have in common?

10. There are 20 naturally-occurring amino acids, and each one only varies in the structure of theR side chain. Two amino acids are shown in Model 1. What are the R side chains in each?

Read This!During chemical reactions, the bonds in molecules are continually broken and reformed. To break a bond, energy must be absorbed. When bonds are formed, energy is released. If more energy is released than absorbed during a chemical change, the process can be used as a source of energy. A general rule for processes such as respiration is the more carbon atoms there are in a molecule, the more energy that molecule can provide to the organism when it is used as food.

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Biological Molecules

11. Using the information from above, is a carbohydrate or a lipid more likely to be a good source ofenergy for an organism?

Model 2 – Biochemical ReactionsA. B.

C

R

H

N C

O

OH

H

HC

R

H

N C

O

OH

H

H

C

R

H

N CH

H

O

C

R

H

NH C

O

OH

+

Amino acid 1 Amino acid 2

Dipeptide

+ H2O

O

OH

HH

H

OH

OH

H OH

H

OH

O

H

OH

OH

H

CH2OH

OH CH2OH

H

O

HH

H

OH

OH

H OH

H

OH

O

O

H

OH

OH

H

CH2OH

CH2OH

H

+

Glucose Fructose

+ H2O

C.

C

O

(CH 2)14CH 3OH

C

CH

H

H OH

CH

H OC

CH3

O

OH

+

C

CH

H O

CH

H OC

CH3

O

OHH

(CH 2)14CH 3

O

Monoglyceride

Fatty acid

Diglyceride

+ H2O

Glucose

Sucrose

Dipeptide

Fatty acid

Diglyceride

Amino acid 1 Amino acid 2

Monoglyceride

Fructose

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POGIL™ Activities for High School Biology

12. What are the reactants of reaction A?

13. What are the products of reaction A?

14. Each of the reactants in reaction A is a single sugar molecule, also called a monosaccharide. Whatprefi x before saccharide would you use to describe sucrose?

15. What are the reactants of reaction B?

16. When the two molecules in reaction B are joined together, what other two molecules are pro-duced?

17. What product do all three reactions in Model 2 have in common?

Read This!When sugars are joined together the new bond that forms is a glycosidic bond. When amino acids are joined the new bond that forms is a peptide bond. When fatty acids are joined to a glycerol the bond that holds them is an ester bond.

18. On the diagrams in Model 2, circle and label the glycosidic, peptide, and ester bonds.

19. These reactions are all referred to as dehydration synthesis or condensation reactions. With yourgroup develop an explanation for why these terms are used to describe these reactions.

20. These reactions can also be reversed, breaking the large molecule into its individual molecules.What substance would need to be added in order to reverse the reaction?

21. Lysis means to split or separate. What prefi x would you add to lysis to mean separate or splitusing water?

22. Using your answers to the previous two questions, what word is used to describe the reaction thatuses water to break apart a large molecule?

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Extension Questions23. Metabolism is the collective term used to describe all the chemical reactions taking place inside

living organisms. Why is water so important for metabolic reactions?

24. We store excess food in our body either in the form of carbohydrates (in muscles and the liver)or as fat (adipose tissue). When our body needs additional energy it uses the carbohydrate sourcefirst as a source of “quick” energy, then the fat. Why do you think carbohydrates are used as asource of quick energy rather than fat? Use complete sentences and scientific terminology in yourresponse.

25. Look at the two types of fatty acids below, saturated and unsaturated. What is the differencebetween the two?

C

C

C

C

C

H H

H H

H H

HH

HH

H

OH O

C

C

C

C

C

H

H

H H

HH

HH

H

OH O

Saturated Fatty Acid Unsaturated Fatty Acid

26. Saturated fats are solid fats, like the animal fats lard and butter, whereas unsaturated fats are morefluid and form oils, such as vegetable oil. Trans fats are plant oils that are artificially solidifiedto make them suitable for baking purposes. In recent years trans fats have been associated withnegative health issues and are not as widely used. Explain in simple molecular terms what wouldhave to be done to a plant oil to transform it to a trans fat.

Saturated Fatty Acid Unsaturated Fatty Acid

Homework: Each person should bring in one food/box/wrapper with a nutrition label for our next activity.6

Macromolecules+Objec(ves"10","11"

Carbon+Compounds++• All"life"is"built"on"carbon"• 4"valence"electrons"• Forms"4"covalent"bonds!"• Lots"of"possibili(es"

• In"Cells"• ~"72%"H2O"• ~"25%"Carbon,based"Biomolecules*(macromolecules)*• Carbohydrates"• Lipids"• Proteins"• Nucleic"Acids"

• ~"3%"salts"(Na,"K,"Ca)"

Carbon+Compound+Shapes++

Made"possible"by"carbon"(and"these"molecules"only"have"C"and"H)"

Building+Biomolecules+• Biomolecules"are"BIG"• Aka"Macromolecules"

• Most"are"long"chains"of"repea(ng"subunits"• All"except"lipids"

• Smaller"organic"molecules"(monomers)"join"together"in"a"chain"to"form"polymers.*

• Linked"by"covalent"bonds"

Building+Biomolecules+• Dehydra(on"Synthesis"• Joins"monomers"by"removing"water"• Requires"energy"and"enzymes"

Dehydra(on"Synthesis"(Condensa(on"Reac(on)"

Synthesis"means"“to"build”"

Digesting+Biomolecules+• Hydrolysis"• Reverse"of"dehydra(on"synthesis"• H2O"added"to"break"monomers"apart"

“Hydro”"means"“water”"

“Lysis”"means"“cu^ng”"

Hydrolysis"(Diges(on"Reac(on)"

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Carbohydrates+Monomer* Dimer*(2*monomers)* Polymer*

Monosaccharide"(simple"sugar)"

Disaccharide" Polysaccharide""

Proteins+Monomer* Dimer* Polymer*

Amino"Acid" Dipep(de" Polypep(de"

Polypep(de"structure"

Nucleic+Acids+Monomer* Polymer*

Nucleo(de" Nucleic"Acid"

• RNA"• 1"long"chain"of"nucleo(des"• Linked"by"dehydra(on"synthesis"

• DNA,"the"“double"helix”"• 2"long"chains"of"nucleo(des"twisted"together"

Lipids+• Not"a"Polymer"(no"repea(ng"subunits)"• 1"glycerol"• 3"fa_y"acid"chains"• Linked"by"dehydra(on"synthesis"

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Analyzing Nutrition Labels

Metabolism is the sum of chemical reactions in your body. Your body uses chemical reactions to break down food, release energy, build new cell parts, produce heat, and much more. Foods you eat include macromolecules (large molecules) that your digestive system can break down for energy. These molecules include carbohydrates, protein, and fats. (Note that these are 3 of the four major types of biomolecules. Nucleic acids are the 4th type, but we do not get much energy from them.)

Activity 1: Calculating Kilocalories

You are going to figure out the amount of kilocalories (energy) in each of the foods you analyze. Use the kilocalorie chart below to make your calculations. Remember that foods with more kilocalories contain more energy.

Kcal per gram

Fat 9

Protein 4

Carbs 4

Name of food # Kcal from fat # Kcal from protein # Kcal from carbohydrates

Activity 2: Basal Metabolic Rate (BMR) Basal metabolic rate is the amount of energy (in the form of calories) the body needs in order to function while resting for 24 hours. BMR depends on several factors including age, sex, and height. It is possible to estimate your BMR using the formula below:

For men: BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) + 5 �� For women: BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) – 161

Calculate the BMR for the following people: 1. A 20-year-old woman who is 175 cm tall and weighs 72 kg.

2. A 20-year-old man who is 175 cm tall and weighs 72 kg.

3. A 40-‐year-‐old woman who is 175 cm tall and weighs 72 kg.

Calculate your BMR.

*Note: food labels use the word “calories” to make things sound simple. Really, labels list“kilocalories” in the food.

1 ft = 30.5 cm 1 lb = 0.45 kg

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Activity 3: Activity Energy

BMR is the amount of energy you use without doing any physical activity. To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows:

•. If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2 •. If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375 •. If you are moderately active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55 •. If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725 •. If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9

1. Calculate the kilocalories you use everyday (your BMR + Kcal for daily activities)

2. How many kilocalories would you use everyday if you were alumberjack (extra active)?

Activity 4: Kilocalories and Food Groups

Answer the following questions in complete sentences. 1. List 3 foods people eat even though they provide very little energy.

Why do you think people eat these foods?

2. Refer back to the foods you analyzed in Activity 1. How many servings of your foods would you need to eat per day to meet your energy needs? Explain your answer.

Homework Look at the nutrition label to the right. Type and submit answers to ONE of the following questions. (Remember the writing guide!)

1. Describe the carbohydrate content of this food.• List the categories of carbohydrates present.• What specific molecules are likely present in the 41 grams

of “Total Carbohydrate”? (Name several.)• From which ingredients does each molecule come?

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6

Vitamin/Mineral What does it do for you?

Food Sources Deficiency Info Does your island food have enough of this?

Vitamin A

Vitamin B6

Vitamin D

Iron

Calcium

Magnesium

Zinc

Vitamins and Minerals

Define the following:

Vitamin ___________________________________________________________________________________________________________________________________________

Mineral ___________________________________________________________________________________________________________________________________________

Use the Internet to complete the chart below. On the back of this page, record any sources you use. You should choose only credible sources.

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Cite your sources using MLA format in the space below.

1.

2.

3.

4.

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Nucleic Acids

monom

er

_______, _______, _______, _______

Elements alw

ays present

___________, _____________

examples

Proteins

monom

er

_______, _______, _______, _______,

and sometim

es _________ Elem

ents present

__________________________

__________________________

__________________________

__________________________

examples

polymer

Carbohydrates

Organic M

olecules Elem

ents always present: _______, ______

Elements that m

ay be present:

_______, _______, _______, _______

monom

er

_______, _______, _______

In 1:2:1 ratio Elem

ents always present

examples

__________________________

__________________________

__________________________

Lipids Nonpolar m

olecules

_______, _______, _______

Elements alw

ays present

__________________________

__________________________

__________________________

__________________________

examples

A major com

ponent.

Straight chain Solid at room

temp.

Bends/ kinks Liquid at room

temp

Objectives 13 -‐ 15: In Class

14

Sucrose

Glucose Fructose

Carbohydrates Proteins

Organic Molecules

Nucleic acids

Maltose

Disaccharides

Monosaccharides

Polysaccharides

Starch Cellulose Glycogen

(100’s of monom

ers) OR

Polypeptide

Amino acid

Triglyceride

Phospholipid

Fatty acids

Saturated Unsaturated

Lipids

Steroid structures

Objectives 13 -‐ 15: In Class

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Begin your discussion about food choices with your group. Come up with a few ideas for possible “desert island foods”. Foods we are considering:

The Assignment – A RESEARCH Project At the end of this project, your team will give a presentation that answers the question, “what two foods could you bring with you to a desert island to keep yourself alive for four months?” You should always include a hypothesis or thesis statement in your research projects. In this case, your hypothesis should deal with which two foods you have chosen, and your research should give evidence to support your choices. (Note: as you accumulate information, you may decide to change or modify your original food choices. That is ok. A true thesis statement/hypothesis is only developed after background research is conducted.)

Over the next week, your group will meet for 2 class periods; check the calendar for dates. Two classes will go by quickly; focus yourselves and use time wisely. Here are some things you might consider:

• Do outside research to find information that will help answer your question.• Review the previous night’s homework assignment. Relate the topics covered in the homework to

your “Survivor: Galapagos Islands” food choices.• Plan and create a presentation

This packet contains several resources to help you navigate this project (be sure to use them!):

Presentation Guidelines: • You do NOT need to repeat information that has been covered by your textbook; assume your

audience already has this information.• Humans need a variety of different nutrients in order to survive. It is not sufficient to only

demonstrate that your foods contain the three major categories of biomolecules. You may choose to discuss

o Different types of fatty acids (trans, cis, omegae 3, omegae 6, etc.)o Essential vs. none essential amino acidso Water soluble vs. lipid soluble vitamins

• Include calculations of calories: how many servings of your foods will you need to reach your BMI? How many times a day will you eat?

• Use a variety of credible sources. Include a works cited slide and ine text citations in your presentation. (Note: ALL sources in your works cited should be cited in the text as well.)

Congratulations!! You have been selected to participate in the reality TV show “Survivor: Galapagos Islands”! The producers have informed you that you must choose two foods to bring with you. Choose wisely….. you may need to survive on only those two foods for up to four months! You will have plenty of fresh water available. Start packing; your plane to the Galapagos leaves in two weeks!

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Activity: Protein Folding with Tacks and Toobers

Explore the forces that drive protein folding with 15 tacks and a 4 foot toober. The color-coded tacks represent the sidechains of the following amino acids:

Instructions 1. Distribute the 15 tacks randomly but evenly along the toober. By doing this, the “tacked toober” represents a

protein made of 15 amino acids.

2. Fold your protein, following the laws of chemistry that drive protein folding. (These laws of chemistry are reviewed in the table below.)

Blue Tacks (2) basic amino acids (+ charge)Red Tacks (2) acidic amino acids (- charge)Yellow Tacks (6) hydrophobic amino acidsWhite Tacks (3) polar amino acidGreen Tacks (2) cysteine amino acid

1155 ttaacckkss

Basic Laws of Chemistry that Drive Protein Folding Stably folded proteins simultaneously satisfy several basic laws of chemistry including:

1. Hydrophobic sidechains (yellow tacks) will be buried on the inside of the globular protein, where they are hidden from polar water molecules.

2. Charged sidechains (blue and red tacks) will be on the surface of proteins where they often neutralize each other and form salt bridges.

3. Polar sidechains (white tacks) will be on the surface of the protein where they can hydrogen bond with water.

4. Cysteine sidechains (green tacks) often interact with each other to form covalent disulfide bonds that stabilize protein structure.

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Questions1. Compare the shape of your folded toober to those of other lab groups. Why are they all shaped differently

Basic Laws of Chemistry that Drive Protein Folding Stably folded proteins simultaneously satisfy several basic laws of chemistry including:

Straighten out your toober and remove all pins. Replace pins in a random order, then re-fold your toober based upon this new amino acid sequence.

2. Did you have greater difficulty with one or the other foldings? Explain.

Consider this: the 30,000 proteins encoded by the human genome have been selected from an enormous number of possible amino acid sequences based on their ability to spontaneously fold into a stable structure that simultaneously satisfies these basic laws of chemistry.

Reversible Denaturation Many proteins undergo reversible denaturation, by re-folding into their original shape (native structure) following their complete unfolding (denaturation) by heating.

• Take a photo of your folded protein.• Unfold your protein, then try to refold it using only the basic folding rules.• Check the refolded protein against the photo of the original structure.

Reverse EngineeringHow can we arrive at a perfectly optimized sequence of tacks that have been selected over evolutionary time to always fold into the same globular shape? ANSWER: By reverse engineering the sequence!

• Fold your toober into a compact globular shape without any tacks.• Next, add the tacks to the pre-folded toober, positioning them such that all of the “laws of chemistry” are

satisfied in the folded structure.• Unfold the toober and document the sequence of tacks.• Then re-fold the sequence into the original shape (see reversible denaturation, above).

The Effect of MutationsA mutation occurs when there is a change to an amino acid sequence. Some mutations inactivate a protein by destabilizing its native shape. • Starting with the “reverse engineered” sequence of tacks as described above, mutate one of the hydrophobic

amino acids (yellow tack) to a positively charged amino acid (blue tack).

3. Did your new protein look similar to your original protein?

4. How might the ability of a protein to undergo reversible denaturation be beneficial to cells?

5. Can you fold this mutated sequence back into its native shape? Explain your answer.

Review Questions: Chemistry of Life, Part II

1. Identify the following molecules by both name and category (carbohydrates, protein, lipid, ornucleic acid).

2. Complete the following chart, comparing different polysaccharides.

Part II: Match each question to the correct biomolecule(s). Answers may be reused, and many questions will have multiple answers.

A. CarbohydratesB. LipidsC. Proteins D. Nucleic AcidsE. None of these

1. Biomolecules the human body can use for energy. __________________

2. Contains only carbon, hydrogen, and oxygen. __________________

a. Contains approximately equal numbers of oxygen and carbon. __________________

3. Carries encoded information. __________________

4. Polymer of amino acids. __________________

5. Polymer of monosaccharides. __________________

Review Questions: Chemistry of Life Part II

1. Identify the following molecules by both name and category (carbohydrate, lipid, or protein).

2. Order the following from small to big: electron, insulin molecule, cell, water molecule, oxygen atom

3. Complete the following chart, comparing different polysaccharidesMade by plants or animals?

Use for organism thatmakes the molecule

Can humans hydrolyze(degrade) it?

StarchCelluloseGlycogen

4. What hormone increases glycogen levels (and therefore decreases blood glucose levels)? _________ Where is this hormone made? __________ What hormone decreases glycogen levels (and thereforeincreases blood glucose levels)? ___________ Where is this hormone made? ____________

5. The following set of questions refers to the molecule below:

a. What type of molecule is pictured above? ______________b. What special type of covalent bond links its monomers together? ___________c. What is the monomer from which this polymer is synthesized? ____________

Daley Biology H 2013-2014

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!





Use for organism that makes the molecule

Can humans hydrolyze (degrade) it?






11

!

16

6. Hydrophobic. __________________

7. Hydrophilic. __________________

8. Forms by dehydration synthesis. __________________

9. Contains nitrogen. __________________

10. Some examples contain carbon, but no hydrogen. __________________

11. ATP is an example. __________________

12. Monomers are joined by peptide bonds. __________________

13. Important examples include enzymes, hormones, antibodies. __________________

13. 14.

15. 16.

17. 18.

19. 20.

17

21. 22.

23.

Part III: Building/Breaking Down Polymers 1. The following set of questions refers to the diagram below.

___________________ + ______ à ___________ + ____________ a. On the lines below the diagram, name the molecules shown in the chemical

reaction.b. What is this chemical reaction called? _________________________c. Will water be formed or used in this reaction? _________________________

2. The following set of questions refers to the molecule below.

+ à ______________________ + __________

A. Fill in the structural formulas to complete the chemical equation on the lines above.

B. What monomers are involved in this reaction? _________________________

C. What special type of covalent bond will join these two monomers?

_________________________

D. What is this reaction called? _________________________

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A. What type of molecule is pictured above?

B. What is the monomer from which this polymer is synthesized?

C. Will water be formed or used if this polymer is degraded into monomers?

D. How many molecules of water will be formed or used?





Use for organism thatmakes the molecule

Can humans hydrolyze(degrade) it?






11

!

19

“Mystery in Alaska” by Dinan, Stabler, & Larson

byFrank J. Dinan, Thomas R. Stabler, and Renee A. LarsonDepartment of Chemistry and BiochemistryCanisius College, Bu! alo, NY

Part I – West vs. EastStudies conducted by the Alaska Fisheries Science Center of the National Marine Mammal Laboratory have established that Steller sea lions have been disappearing at an alarming rate in Alaskan waters. Since the !"#$s, these marine mammals have experienced a severe overall decrease in population, but the decrease has not been uniform. % e region from the Prince William Sound through the Aleutian Islands has observed an &'–"$( decrease in the abundance of these creatures; this region contains the Western stock of Steller sea lions, as illustrated in Figure !. % e Eastern stock, also seen in Figure !, is located on the southeast coast of Alaska and its Steller sea lion population is increasing modestly (Figure )).

Figure 1. Distribution

Mystery in Alaska: Why Have All the Sea Lions Gone?

Credits: Figure ! courtesy of the Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration (NOAA). Photo of Stellar sea lions in Resurrection Bay by Frank Kovalchek, Creative Commons Attribution 2.0 License.

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Figure 2. Steller Sea Lion Populations

Estimated numbers of Steller sea lions (all ages) in Alaska from 1956 to 2000 (from Trites & Larkin, 1996; A.W. Trites, unpublished data). Figure used with permission of the North Pacifi c Universities Marine Mammal Research Consortium.

% ere is particular concern regarding the Western stock of sea lion pups. Most of these juveniles don’t survive more than three years and therefore many do not reach sexual maturity, which occurs in males between * to & years of age and in females at an average age of +., years (Pilcher, !"&!). Because of their small size, the sea lion pups are more vulnerable to changes in their environment and are less able to adapt to these changes. While they have higher energy needs for growth and development, the pups are inexperienced hunters, ine- cient at catching prey, and largely dependent on their mothers for survival.

Questions!. List several possible reasons for the decline of the Steller sea lion population.

). Can any of your reasons explain why the Western sea lion stock is decreasing and the Eastern stock is modestly increasing? If so, how?

ReferencesPilcher, K.W., and D.G. Calkins. !&"!. Reproductive biology of Steller sea lions in the Gulf of Alaska.

Journal of Mammalogy '$,–""' :)*(),.Trites, A.W., and P.A. Larkin. ,""!. Changes in the abundance of Steller sea lions (Eumetopias jubatus) in

Alaska from ,'"! to )""!: How many were there? Aquatic Mammals ,,!–*'! ,*.)). http://www.marinemammal.org/pdfs/TritesLarkin#""!-abundance.pdf

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http://www.marinemammal.org/pdfs/TritesLarkin1996-abundance.pdf


Part II –Pollock vs. HerringSteller sea lions are powerful predators, feeding on almost any smaller fi sh found in their habitat. However, two fi sh comprise a majority of the sea lions’ diet: pollock and herring. Herring are small schooling fi sh that can be fed upon in large numbers. Contrastingly, pollock are larger, more solitary, and di- cult for the sea lions to catch and digest.

In !"#$, the Federal government, prompted by environmental groups that argued that the pollock population was declining in western Alaskan waters, introduced a ban on the commercial fi shing of pollock from the southwestern coast of Alaska through the Aleutian Islands. % is ban altered the western waters’ ecosystem, but left that of the waters along the southeast Alaskan coast largely unchanged. While fi sh populations in the southeast remained unchanged, relative fi sh populations in the southwest fl ip-fl opped, with herring becoming less plentiful and pollock more abundant. (A portion of the fi sh community was salmon, and this remained unchanged with the change in fi shing regulations in both the southwest and southeast.)

As the ecosystem in southwest Alaskan waters changed, the population of the Western stock of Steller sea lions also changed. A census of the populations of pollock, herring, and the Western stock of Steller sea lions in southwest Alaska disclosed striking trends, which are illustrated in Figure *. It was also observed that the Western stock exhibited a far higher pup fatality rate than that observed in the Eastern stock (Rosen, )$$$).

Steller sea lions give birth to a single pup. % e age of weaning for pups is variable, ranging from one to three years. While the pups suckle, they do not hunt and are dependent on their mothers for food (Alaska, )$$#).

% e data in Figure * show the trends in the relative numbers of pollock, herring, and sea lions (% orne, )$$").

Figure 3. Population Trends

Graph based on based on ! orne, 2009.

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Part III – Diet vs. Energy RequirementsAn experiment was conducted at the Vancouver Aquarium Marine Science Centre to compare the relative e. ects of eating pollock and herring on Steller sea lions (Alaska Fisheries Science Center, !""+). Releasing live, swimming prey for sea lions to chase and capture in two very large tanks simulated the natural habitat of the Steller sea lions. % e fi rst group of sea lions was placed in a tank where they preyed upon herring as their only food source. A second sea lion group preyed exclusively on pollock in an otherwise comparable second tank. % e sea lions were allowed to eat as much of each of these types of fi sh as they desired. % ose fed herring all gained weight during the course of the experiment while those consuming exclusively pollock all lost weight.

% is experiment was then extended for the second group. % is group’s diet was switched so that they ate strictly herring rather than pollock. Under these conditions, the sea lions reversed their weight loss and experienced a steady weight gain. It was also noted that sea lion pups exhibited the most dramatic weight losses and gains during each of these experiments.

% e researchers compared the amount of energy available to the Steller sea lions when eating pollock to that available when they fed on herring. Pollock is a lean, low fat fi sh; it contains !( fat and )$( protein and #"( carbohydrate. Herring is a fatty fi sh; it contains !$( fat, !"( protein, and #!( carbohydrate (Donnelly, )$$*). It was also found that the larger pollock is a more di- cult fi sh for the sea lions to digest than the smaller herring.

% is experiment highlighted the importance of meeting energy requirements for marine mammals to live healthy lives. % ere are three general types of foods from which sea lions obtain energy: fats, carbohydrates, and proteins. Fats contain " calories per gram while proteins and carbohydrates a. ord only + calories per gram. To thrive, any species must consume food that provides enough net energy to sustain a healthy body.

Calculations!. Calculate the number of calories a sea lion would consume when eating !$$ grams each of pollock and

herring. Base your calculations on the fat, carbohydrate, and protein content of each of these fi sh.a. Total calories per !$$g of pollock = fat contribution + protein contribution + carbohydrate contributionb. Total calories per !$$g of herring = fat contribution + protein contribution + carbohydrate contribution

). Calculate the percent of calories obtained from fat, carbohydrate, and protein in both herring and pollock.

Questions!. Based on your calculations, which fi sh—pollock or herring—better meets the energy needs of the

Steller sea lions?

). Since the sea lions in each tank were allowed to eat unlimited amounts of prey, why did they lose weight when eating pollock? Why could they not just eat more pollock to maintain or increase their weight?

*. What is the signifi cance of the fact that the sea lion pups were a. ected more than the adults? Why werethe pups especially impacted? Explain your reasoning.

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Case copyright ©)$$" by the National Center for Case Study Teaching in Science. Originally published September )), )$$" at http://www.sciencecases.org/sea_lions/case!.asp. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this case study.

+. Using all of the information and the inferences you have drawn above, clearly explain why the Westernstock of the Steller sea lion population is decreasing while that of the Eastern stock has remained steady in the !"#$s and has increased modestly.

'. Propose a measure or measures that could be implemented to reverse the decline in the Western stock of Steller sea lions. Would you expect both support and opposition to the measure that you propose? If so, where would the opposition and support for your proposal come from?

ReferencesAlaska Fisheries Science Center. National Marine Mammal Laboratory: Marine Mammal Species. !""+.

http://www.afsc.noaa.gov/nmml/species/species_steller.php Last accessed: '/)$/$&.

Donnelly, C.P., A.W. Trites, and D.D. Kits. )$$*. Possible e. ects of pollock and herring on the growth and reproductive success of Steller sea lions. British Journal of Nutrition **: #!–&).

Fritz, L.W., and S. Hinckley. )$$'. A critical review of the regime shift—“junk-food”—nutritional stress hypothesis. Marine Mammal Science )!: +#,–'!&.

NoteWe have explored only one of the hypotheses that could account for the decline in the Western stock of Steller sea lions. Others exist that could also account for this decline. For example, a climate shift occurring in the region has also been proposed as a contributing cause (see Fritz and Hinkley, )$$'). Time considerations prevent us from exploring these alternative proposals.

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http://ublib.buffalo.edu/libraries/projects/cases/guidelines.html

http://www.afsc.noaa.gov/nmml/species/species_steller.php

http://www.sciencecases.org/sea_lions/case1.asp

http://ublib.buffalo.edu/libraries/projects/cases/case.html

The following diagrams may help you with your notes. Cut and paste them into your notebook to help you answer objectives.

Objective 13:

Objective 14:

A triglyceride (fat)

Objective 14: Explain what an organic compound is and why they are important for life (1.6).

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Objective 15: Define and relate the terms macromolecule, polymer, monomer, and polymerization (1.6 and class notes).

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Objective 16: Describe and relate the terms: biosynthesis (dehydration synthesis), and decomposition (degradation hydrolysis) (2.7).

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Objective 17: Describe (and identify a diagram of) the structure and importance of carbohydrates – including monosaccharides, disaccharides, and polysaccharides (1.7).

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Objective 15:

Objective 16:

Objective 16:

Objective 18: Describe (and identify a diagram of) the structure and importance of lipids – including phospholipids and cholesterol (1.8).

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zig zags are hydrocarbon chains

Objective 19: Explain the difference in structure between unsaturated and saturated lipids and explain why eating one type is better for your health than the eating the other (1.8).

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Objective 20: Describe the structure and importance of proteins, including how polypeptides are formed (1.9). _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Objective 21: Describe the four levels of structure in a protein (1.9).

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Objective 20: Describe the structure and importance of proteins, including how polypeptides are formed (1.9). _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Objective 21: Describe the four levels of structure in a protein (1.9).

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Objective 18:

Objective 22: Describe some ways that structure is important for function of a protein (1.9).

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Objective 23: Describe the structure and importance of nucleic acids (1.10).

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A nucleotide contains: _______________________________________________________________________


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Unit 1: Chemistry of Life, Part II: Biochemistrymsdaley.weebly.com/uploads/8/7/2/0/8720335/biochem... · · 2016-09-20PACKET #2 Unit 1: Chemistry of Life, Part II: Biochemistry