Biology CP Name Date Period

HOMEWORK PACKET

UNIT 2B: Basic Biochemistry

Part 1 – Carbs, Lipids, Nucleic Acids

Introduction: Biochemistry

1. Classify each of the following as Organic (O) or Inorganic (I).

_____ C284H432N84O79S7 _____HBr _____ C56H58Cl14CuN16S4 _____B3H3N6 _____ C14H8O4

_____ C10H12N3O3PS2 _____GaCl3 _____SiH4 _____C19H22N2S _____C9H8O4

2. Select which of the following describe Hydrolysis (H) or Dehydration Synthesis (DS)

_____ builds larger compounds

_____creates smaller compounds

_____water is produced

_____water is required

3. A scientist analyzes several foods and determines the following (each answer is used only once):

Grams per Serving Food Protein Carbohydrate Lipids Cholesterol FiberA 103.9 0 26.9 334 0B 0 0 38.4 0 0C 36.3 203.4 1.0 0 25D 0.2 102.3 0.1 0 10.2E 0 200 0 0 0

______1) Which of the above foods is most likely a lowfat bran muffin?______2) Which of the above foods would be the oil you mix in salad dressing?______3) Which of the above foods is most likely a cola?______4) Which of the above foods is most likely a piece of steak?______5) Which of the above foods is most likely a pear?

4. Which element is being described: Can form 4 bonds Can form single, double or triple covalent bonds Found in all organic compound

Choices: a. Carbon b. Hydrogen c. Nitrogen d. Oxygen

5. True or False?

_____Monomers are the building blocks of polymers.

_____Dehydration synthesis produces monomers from polymers_____ Organic compounds are found in living things while inorganic compounds are only found in the abiotic environment._____ Hydrolysis takes place in humans while synthesis only takes place in plants.

1

HW: Introduction to Organic Compounds

1. Compare and contrast inorganic and organic compounds on the following basis:

Description: Inorganic Organic

Elements present in each

Are they found in living things?

Are they produced in living things?

2. List three different foods that would be a rich source of each of the four types of organic compounds we will study in class.

Type of Organic Compound 1st type of food 2nd food 3rd food

1.

2.

3.

4.

3. Which of the following structures is an organic compound? (Label each as organic or inorganic.)

2

Carbohydrates

______1. What do glucose, fructose, and galactose have in common? (choose all that apply)

a) they are monosaccharides c) they are isomers

b) they are disaccharides d) they are proteins

Answer the next two using numbers:

2. Hydrolysis of a trisaccharide produces ________ molecules of simple sugars.

3. Synthesis of a disaccharide requires ________ molecules of a monosaccharide.

4. What are the four types of organic compounds we plan to study in this class?

a. ______________________________ c. ______________________________

b. ______________________________ d. ______________________________

5. Which of the above categories includes DNA? ___________________________

6. Define the word structure: _______________________________________________________________

7. Define the word function: _______________________________________________________________

8. The major theme of Biology is “Form leads to Function.” Give an everyday analogy of this theme and explain how it applies to Biochemical molecules. Make sure you use the two, bold-faced words in questions 6 and 7 in your answer.

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

3

9. The structure below is table sugar, tell me as much as you can about 1) what types of food it is found in, 2) the classification of the type of molecule it is, 3) what types of elements it contains, 4) the dissolvability of the molecules in

water and why, and 5) what would result if the molecule was to undergo hydrolysis. Write your answer in paragraph format.

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

10) Compare and contrast inorganic and organic compounds on the following basis:

Description: Inorganic Organic

Elements present in each

Are they found in living things?

Where are they produced?

11) What is the general name for a carbohydrate made of many simple sugars?

___________________________

12) What is the name of the simple sugar used to synthesize starch, glycogen and cellulose?________________4

13) Use the words in italics to fill in the following concept map: polysaccharide, simple sugar, intermediate molecule.

two combined many combined

14) Fill in the following chart by listing the three important polysaccharides above in the first column below.

POLYSACCHARIDE

TYPE OF ORGANISM THAT SYNTHESIZES

THE POLYSACCHARIDE

SIMPLE SUGAR USED TO SYNTHESIZE THE

POLYSACCHARIDE

FUNCTION OF THE POLYSACCHARIDE IN THE

ORGANSIM

starch

glycogen

cellulose

15) Complete the following analogies:

a) glycogen is to animals as starch is to _______________________________

b) glucose and fructose are to sucrose as _______________________ is to starch.

c) synthesis is to build as hydrolysis is to ______________________________

d) simple sugar is to glucose as polysaccharide is to _______________________(3 possible answers)

16) List 3 foods that contain a large amount of cabohydrate:

___________________________________________________

___________________________________________________

___________________________________________________

17) Define synthesis (dehydration synthesis) of carbohydrates

_______________________________________

5

18) Define hydrolysis of carbohydrates

_________________________________________________________

19) What is the name of the process by which plants make glucose? _________________________________

20) Name two carbohydrate molecules that a plant synthesizes or makes from glucose.

____________________________ and ____________________________________

21) Animals cannot make glucose. How do they obtain it? __________________________________________________________________________________________

_______________________________________________________________________________________

22) Name the carbohydrate molecule that animals make from glucose. ________________________________

Choose from the following to answer questions 23 and 24. Choose all answers that apply.

a. used as a reactant in cell respiration d. used as a form of energy

b. composed of carbon, hydrogen and oxygen e. contain many covalent bonds

c. form plant cell walls f. contain –OH (hydroxyl groups)

_____________23. Which of the above is considered a structural characteristic of carbohydrates?

_____________24. Which of the above is considered a functional characteristic of carbohydrates?

___________________ 25. Which of the following IS a carbohydrate? Choose all that apply.

a. sucrose d. lactose g. carbon dioxide

b. water e. DNA h. glucose

c. polysaccharide f. cellulose i. simple sugar

6

____________ 26. Which of the following is composed of at least one molecule of glucose? (choose all that apply)

a. galactose b. cellulose c. lactose d. glycogen

_______27) Which of the following is a TRUE statement a. carbohydrates contain many atoms of nitrogen b. monosaccharides can be hydrolyzed to form disaccharides c. cellulose can be hydrolyzed to form glucose and fructose molecules d. glycogen can be synthesized from glucose molecules

_______ 28) Which of the following terms could be used to describe table sugar?(Choose all that apply)

a. monosaccharide c. polymer e. disaccharideb. dimer d. organic compound f. monomer

_______29) Which of the following are inorganic compounds found in all living things?

a) glucose c) water e) table sugarb) NaCl d) starch f) oxygen

_______ 30) List three types of food that would contain a large amount of monosaccharides.

a. ____________________ b. ____________________ c. ___________________

______ 31) Synthesis of a carbohydrate from monomers could produce (choose all that apply)

a. starch c. glucose e. fructoseb. dimers d. polysaccharides f. DNA

32) Fill in the following table:

Name of Polysaccharide

Organism that produces this molecule

Monomer unit that is used to make this polysaccharide

General Function of this polysaccharide

Starch

Cellulose

Glycogen

33) Describe in your own words (not using pictures) the structural difference between cellulose and glycogen.

7

Lipids

1) What are the smaller molecules that make up fats and oils? _______________________________________

_______________________________________________________________________________________

2) What is the process by which lipid molecules are synthesized or made?______________________________

3) What is the difference between the chemical structures saturated and unsaturated fatty acids?

_______________________________________________________________________________________

_______________________________________________________________________________________

4) Use your notepacket and draw the structural formula of an imaginary saturated fatty acid using 5 carbons:

5) Redraw your molecule as an unsaturated fatty acid (use 5 carbons):

6) What did you add and/or subtract to build the unsaturated fatty acid?_______________________________

_______________________________________________________________________________________

7) Is your unsaturated fatty acid monounsaturated or polyunsaturated (mono means on C=C and poly means

more than one C=C)?_________________________________

8

8) Describe the difference between an oil and a fat based on:

a) Which contains saturated fatty acids? Unsaturated?____________________________________

_____________________________________________________________________________

b) Give three examples of foods that have fat in them _____________________________________

______________________________________________________________________________

c) Give three examples of foods that have oil in them _____________________________________

_____________________________________________________________________________

9) Which is healthier? (circle one bold-faced word or words per line)

A) Unsaturated or saturated lipid

B) solid or liquid lipid at room temperature

C) animal fat or plant oil

9

Nucleic Acids

1. Complete the following analogies:

a) amino acid is to protein as nucleotides are to _________________________________

b) nucleotide is to DNA as simple sugar is to ______________________________(3 possible answers)

c) enzyme is to protein as RNA is to ____________________________________

d) sugar, phosphate group and nitrogen base are to nucleic acids as amino group, carboxyl group and R

group are to ____________________________

2. What are the main elements found in nucleic acids?

3. What are the monomer units of nucleic acids?

4. Which molecule is in the nucleic acid category but does not form polymers?

5. What are the three parts of a nucleotide?

6. What is the relationship of RNA to DNA?

7. DNA codes for the production of what other type of organic compound?

8. Which of these contain deoxyribose?

a. ATP b. DNA c. RNA

9. Which of these contain ribose?

a. ATP b. DNA c. RNA

10. Which of these stores information?

a. ATP b. DNA c. RNA

11. Which of these stores energy?

a. ATP b. DNA c. RNA

12. Label the nitrogen bases, sugars, and phosphates in the diagram below.

10

REVIEW OF ORGANIC COMPOUNDS

1) What are the four major groups of organic molecules and what are the subunits of each group?

GROUP UNITS USED TO SYNTHESIZE MOLECULES IN THE GROUP

2)

3) Fill in the reactants and products missing in the hydrolysis of the four major organic compounds:

Organic Compound Hydrolysis

Reactant(s) Product(s)

carbohydrate polysaccharide

lipid glycerol + fatty acids

protein amino acids

nucleic acid DNA or RNA

Answer questions 5 to 13 by listing the letters of the following compounds, which apply to each statement.

There may be more than one answer per question.

a) polypeptides

11

b) lipids

c) simple sugars

e) polysaccharides

f) amino acids

g) nucleotides

h) nucleic acids

i) glycerol and fatty acids

5) Which of the above are broken down by hydrolysis?_____________________________________________

6) Which of the above are the simple units used to synthesize organic compounds?_______________________

7) Which of the above are made up of many amino acids? _________________________

8) Which of the above are used to make a triglyceride like oil? ____________________________

9) Which of the above are used as reactants in the synthesis of glycogen? __________________

10) Which of the above are components of DNA? ___________________

11) Which of the above are carbohydrates? _________________________

12) Which of the above contain nitrogen? __________________________

13) Which of the above contain Phosphorus? ________________________

12

End of Unit, Vocabulary Scavenger Hunt

Directions: Use the terms below to fill in the blanks. List the term (or terms) that apply to each statement below.

1) Lipid units that DO NOT have C-C double bonds. These are less healthy than unsaturated

fatty acid chains. _______________________________________

2) This molecule is a single nucleotide that is named after its three phosphate groups. _________________________

3) These compounds do NOT contain both carbon and hydrogen. CO2 is an example. ____________________________

4) This protein is responsible for speeding chemical reactions like the hydrolysis of sucrose into

glucose and fructose. _____________________________________

5) A triglyceride, this molecule is composed of glycerol and 3 unsaturated fatty acid chains. _______________________

6) This monosaccharide is used as a reactant in dehydration synthesis to make glycogen, starch

or cellulose. ____________________________

7) A general term for a molecule composed of two simple sugars. _______________________

8) The type of covalent bond that joins amino acids during dehydration synthesis of a protein. ____________________

9) The general name for a large carbohydrate, protein or nucleic acid that is composed of many

monomer units. ______________________________________________________

10) This molecule holds the information for building proteins. It is found in the nucleus of the

cell. ___________________________

11) A general name for the smallest unit of a carbohydrate, protein or nucleic acid. ____________________________

13

12) Two of these units are used to make table sugar. ________________________________

13) These molecules are unusual lipids that have ring structures. They can be sex hormones or

molecules found in animal cell membranes._________________________

14) A general term that includes dipeptides and polypeptides. ________________________

15) This process will add water to a polymer and break it into monomer units. _______________________________

16) A molecule composed of nucleotides that functions to help when making proteins from

DNA. ____________________________

17) This healthier lipid is characterized by a carboxyl group and carbons that are double bonded

to each other. ________________________________

18) A group of amino acids that functions to do a job in the body. ________________________

19) This polymer is composed of glucose monomers and functions to store energy in plants. _____________________

20) These small units make up a molecule that contains adenine, guanine, cytosine and thymine. __________________

21) A triglyceride, this molecule is found in animal products and is solid at room temperature. ____________________

22) This entire group of molecules does NOT dissolve in water. _________________________

23) A carbohydrate that functions to make the cell wall in plant cells. _____________________

24) A lipid that functions to build the cell membrane in all organisms. ____________________

25) Monomer units of carbohydrates. They are used to make polysaccharides. ______________________________

26) A term that describes any molecule that contains BOTH carbon and hydrogen atoms. ________________________

27) When you eat a potato, you undergo hydrolysis to produce _________________.

28) You then take that molecule and undergo dehydration synthesis in your cells to form

________________________________.

14

29) These molecular groups are found on organic molecules. They are associated with the site

of bonding to form larger molecules during dehydration synthesis. _________________________________

30) These monomer units make up a polypeptide. ________________________

31) Any lipid composed of three fatty acids and a glycerol molecule. ______________________

32) A group of organic compounds that includes simple sugars, table sugar and starch. _______________________

33) The process by which 3 molecules of water are removed from four amino acids to make a

polypeptide. _______________________________

34) A general term that includes fats, oils, estrogen, phospholipids and waxes. This group of

organic molecules do not have polymer or monomer units._______________________

35) The molecule that results when amino acids are combined during dehydration synthesis.

_____________________________________ (two answers).

36) Cellular fuel. _______________________

37) General name for a molecule that contains C, H, O and N (no P). _____________________

38) General name for a molecule that only contains C, H and O. Their name means hydrated

carbons. _______________________________________

39) A major group of organic molecules that contains C, H, O, N and P. ____________________________________.

40) Triglycerides that have fatty acid chains that are saturated with hydrogens. _________________________________

15

Biology CP Name Date Period

HOMEWORK PACKET

UNIT 2B: Basic Biochemistry

Part 2 – Proteins, Enzymes, pH

16

Proteins

1) What are the small, repeating units (monomer units) of proteins called?______________________________

2) What are two different names for the type of bonds which join two protein units?

_______________________________ and _________________________________

3) List the parts of an amino acid: _____________________________________________________________

_______________________________________________________________________________________

4) Draw the general structure of an amino acid. Circle the R group, draw a square around the carboxyl group

and draw a triangle around the amino group.

5) What part of an amino acid differs from one type amino acid to the next? (circle one )

amino group (-NH2-) organic acid (-COOH) central carbon R groups

6) List the name and function of a specific protein: __Hemoglobin caries oxygen in the red blood cell, actin and

myosin are muscle proteins that help our heart to beat and our arm and leg muscles to move, and collagen is a

protein that keeps our skin soft and supple._______________________

7) How many amino acids are combined to form a dipeptide? ___________ a tripeptide? ________________

How large are most proteins? ______________________________________________________________

8) What is the general name of a protein that catalyzes chemical reactions? _________________

9) Give a more specific name for a protein in your digestive system that speeds hydrolysis of lipids.17

_____________________________

10) What happens to the structure of a protein as it is heated to a high temperature? What effect does this have

on its function? _________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

11) Complete the following analogies:

a) amino acid is to protein as glycerol and 3 fatty acids are to _____________________________

b) carbohydrate is to glycogen as protein is to ____Use an example above.________(many possible answers)

c) synthesis is to proteins as hydrolysis is to __________________________________

12) Name 5 foods that are rich sources of proteins.

13) How many amino acids are in the polysaccharide shown below?

How many peptide bonds does it contain?

How many water molecules were created when it was formed?

14) All proteins contain these elements:

18

Biology CP Name Date Pd

Enzymes & pH HW#1

1. What is a chemical reaction?

2. Complete the table about chemicals in a chemical reaction.

Chemicals in a Chemical Reaction

Chemicals Definition

Reactants

Products

THINK VISUALLY

3. The graphs below show the amount of energy present during two chemical reactions. One of the reactions is an energy-absorbing reaction, the other is an energy-releasing reaction.

Draw an arrow on each graph to show the energy of activation.

REACTION "A" REACTION "B"

4. Which of the above reactions would be considered an energy-absorbing (endergonic) reaction? Why?

19

5. Define "activation energy".

6. Of the two reactions shown, which one is more likely to start spontaneously and why?

7. In reaction "A", which would have more potential energy - the products or reactants? (circle one)

8. Which reaction - A or B - shows the creation of products that are smaller & simpler than the reactants? (circle one)

9. Which reaction - A or B - has a higher activation energy? (circle one)

_______10. Regardless of whether an organism makes its own high-energy nutrients or must obtain them by eating, all organisms must perform the following reaction to release energy for the cell(s):

a. photosynthesis

b. cellular respiration

c. fermentation

______11. Would the reaction below be considered an energy-absorbing (endergonic) or energy-releasing (exergonic) reaction?

a. energy-absorbing (endergonic) b. energy-releasing (exergonic)

20

______12. Which example below illustrates a "reversible" reaction?

a. b.

_____13. When chemical bonds are broken, energy is __?__; when new bonds are formed, energy is __?__.

a. released; released c. required; required

b. released; required d. required; released

21

Biology CP Name Date Pd

Enzymes & pH HW#2

Proteins are some of the largest and most complex compounds found in living organisms. Although 70% of your body is made of water, most of the other 30% is protein. A cell's DNA or genetic code determines what types of proteins are made by that cell. As a result, proteins play a large role in determining the structure and function of a cell.

1. Fill in the missing words in the paragraph below.

The words listed below may be used once, more than once, or not at all:

function R groups peptide bonds homeostasis

number types sequence proteins

amino acids organic speed identity

fold DNA polypeptide catalysts

Proteins are one of the four major types of _______________ compounds that we studied in our biochemistry

unit. __________ ___________ are the monomers of proteins. When two or more of these monomers

covalently bond together it forms a polymer called a ___________________. The covalent bonds which join

amino acids are specifically called ___________ ________. When they are first formed (according to the

________ code of a cell), proteins are linear (straight, unfolded) chains of amino acids. Attractive forces (such

as hydrogen bonds) between the ______________ of the amino acids in the chain cause the chain to

______________ up on itself into a 3-dimensional globular shape that is unique to each type of protein.

Remember, form leads to _____________! Once properly folded, polypeptides become functional and are

properly called ____________________. Proteins differ in the _______________, _________________, and

____________________ of the amino acids they contain. A specific group of proteins is called enzymes,

which help to ________________ up chemical reactions in cells. Enzymes are biological ______________

which are critical for the maintenance of ______________ in cells.

22

2. What do we commonly call the organic catalysts found in cells?

3. Why is a catalyst highly effective in small amounts?

4. Enzymes typically have “-ase” at the end of their name like “sucrase”. Look at the picture. Describe what

sucrase does to sucrose.

5. Would the reaction above likely release or absorb energy? Explain your reasoning.

6. How does heat act as a catalyst? Why can't cells rely on heat as their main catalyst for chemical reactions?

7. How does the addition of a catalyst affect the energy of activation of a chemical reaction?

23

8. Using the analogy of a lock and key, explain what the expression “enzymes

are specific” means..

TRUE OR FALSE - if false, correct the statement.

_____9. Enzymes are reusable.

_____10. Substrates strain the bonds of enzyme molecules, reducing the amount of energy needed for old bonds to break and new bonds to form.

_____11. Enzyme-assisted reactions occur much more slowly than they would if the enzyme were not present.

_____12. A particular enzyme can catalyze many different types of reactions.

_____13. Some enzymes assist with hydrolysis, whereas others assist with dehydration synthesis.”

24

Use the diagram to answer Questions 14-15.

14. Label the enzyme, the active site, and the products in the diagram above.

15. Write what is happening at each numbered part of the diagram.

(location #1)

(location #2)

(location #3)

25

Biology CP Name Date Pd

Enzymes and pH HW #3

_____1. Which of the following is a factor which can affect enzyme activity?a. availability (concentration) of enzyme and/or substrate moleculesb. temperaturec. pHd. regulatory moleculese. all of these

_____2. Denaturation of an enzyme will usually change its structure, leading to:a. increased rates of reactionb. decreased rates of reaction

_____3. Which term or phrase is most related to the term "denaturation"?a. unfolding b. refolding c. breaking apart d. putting together

_____4. Enzymes tend not to work well at very low temperatures due to:a. rapid movement of molecules and frequent collisions between substrate & enzymeb. slow movement of molecules and infrequent collisions between substrate & enzyme c. denaturation of enzyme molecules

_____5. Enzymes tend not to work well at very high temperatures due to:a. rapid movement of molecules and frequent collisions between substrate & enzymeb. slow movement of molecules and infrequent collisions between substrate & enzyme c. denaturation of enzyme molecules

_____6. True or False: An enzyme typically works well throughout a wide range of varying temperature and pH conditions.

7. Define homeostasis.

26

8. Based upon your knowledge of enzyme action & denaturation, explain why excessively high temperatures (such as heat stroke or very high fevers) can be dangerous to the human body.

9. What is the name for the region of an enzyme molecule which that binds with a substrate and is most directly affected by denaturation?a. inactive site b. reaction site c. active site d. reactive site

27

Biology Name_________________________Date____________ Period________

Enzymes and pH HW#4 - Enzymes Review

______1. Which statement about enzymes is NOT correct?a. enzymes are polypeptides composed of amino acidsb. an enzyme molecule forms a temporary association with a reactantc. enzymes are destroyed when they are used and must be synthesized for each reactiond. enzymes are specific because of their shape and catalyze only certain reactions

______2. Which of the following enzymes would digest a fat?a. sucrase b. fatase c. protease d. lipase

_____3. At high temperatures, the rate of enzyme action decreases because the increased heat:a. changes the pH of the systemb. alters the active site of the enzymec. neutralizes the acids and bases in the systemd. increases the concentration of the enzyme

_____4. Enzymes influence chemical reactions in living systems by:a. providing the substrate required for the reaction to occurb. affecting the rate at which reactions occurc. absorbing water released when polymers are formedd. combining with excess hydrogen to form gaseous wastes

_____5. Which group of organic compounds do enzymes belong to?a. proteins b. starches c. carbohydrates d. lipids

_____6. The ‘Lock and key model” attempts to explain the mechanism of:a. cell wall formation c. sharing of electronsb. dehydration synthesis d. enzyme specificity

_____7. Any substance that is acted upon by an enzyme is called a(n):a. coenzyme b. substrate c. vitamin d. polypeptide

_____8. An enzyme that hydrolyzes protein will not act upon starch. This fact is an indication that enzymes are:a. hydrolytic b. specific c. catalytic d. synthetic

28

_____9. Salivary amylase is an enzyme in humans that breaks down starch. The optimum pH for this reaction is 6.7. The enzyme's effectiveness will NOT be affected by:a. maintaining the pH of the reaction at 6.7.b. substrate concentrationc. enzyme concentrationd. decreasing the temperature of the reaction by 15 degrees Celsius.

_____10. A certain enzyme will hydrolyze egg white but not starch. Which statement best explains this observation?a. Starch molecules are too large to be hydrolyzed.b. Enzyme molecules act only on specific substrates.c. Egg white is composed of monosaccharides.d. Starch is composed of amino acids.

_____11. Which environmental condition would most likely have the LEAST effect on the rate of enzyme-controlled hydrolytic reactions in humans?a. the pH of the solutionb. the temperature of the solutionc. the amount of enzyme and substrate presentd. the amount of light present

_____12. Gastric Protease and Intestinal Protease are digestive enzymes found in humans. Which statement best expresses the information represented in the graph shown?

a. The action of enzymes varies with pH.b. A pH of 7 provides the optimum environment for all digestive enzymes.c. Gastric protease is active at from pH 0 to 12.d. Acids have a pH greater than 7.

_____13. Lipase, maltase and protease are all members of a group of catalysts known as:a. hormones b. carbohydrates c. lipidsd. enzymes

29

_____14. The effect of temperature on the relative rate of action of an enzyme is represented in the graph below.

The optimum temperature for the action of this enzyme is approximately __?__ degrees Celsius.a. 15 b. 22 c. 37 d. 50

_____15. Here are some stages of an enzyme-controlled reaction:

The stage at which the enzyme is attached to the substrate and straining the substrate's bonds (called an enzyme-substrate complex) is represented by diagram __?__. (choose a, b, c or d)

_____16. The diagram below represents three steps in the hydrolysis of a molecule of sucrose.

In this diagram, structure X is most likely:a. a molecule of oxygen c. an organic catalystb. the end product d. the substrate______17. Which letter represents an enzyme functioning to hydrolyze molecule "A" in the diagram below?

a. A b. B c. C d. D e. E

30

______18. The fact that amylase in the human small intestine works best at normal body temperature (37 degrees Celsius) suggests that:a. amylase is denatured at temperatures below 37 degrees Celsiusb. amylase can function only in the small intestinec. the lock-and-key model of enzyme action does not apply to amylased. the optimum temperature for amylase is 37 degrees Celsius

_____19. Which statement best describes the enzyme represented in the graphs below?

a. This enzyme works best at a temperature of 35 degrees and a pH of 8.b. This enzyme works best at a temperature of 50 degrees and a pH of 12.c. Temperature and pH have no influence on the activity of this enzyme.d. This enzyme works best at a temperature above 50 degrees and a pH above 12.

_____20. Enzyme “X” works best within the range of 20 – 27 degrees Celsius. At which of the following temperatures would this enzyme most likely be denatured?a. 15 degrees b. 20 degrees c. 25 degrees d. 39 degrees

_____21. A student placed groups of 50 seeds in a variety of temperatures ranging from 0 to 50 degrees Celsius. A difference in the rate of germination observed in the groups at different temperatures was most likely due to the effect of temperature on:a. acids b. glycogen c. enzymes d. cellulose

31

Biology CP Name Date Pd

Enzymes and pH HW #5

1. Review your chemistry notes. What happens to an ionic compound when it is placed in water?

2. What do we call a compound that releases H+ ions in solution?

3. What ions does HCl dissociate into?

4. What is a base?

5. Which of the following is true regarding a neutral compound?a. in solution the concentration of H+ ions is the same as the concentration of OH- ions. b. it has a pH = 7c. pure water is an exampled. all of these

______6. Which of the following TWO statements are true regarding buffers?a. Strong acids and strong bases are good buffers.b. Weak acids and weak bases are good buffers.c. Buffers cause dramatic pH changes in organisms. d. Buffers prevent dramatic pH changes in organisms. ______7. What would be the best buffer for a solution with a pH of 12?a. a strong acidb. a strong basec. a weak acidd. a weak base

______8. A solution with a pH of 8 contains __?__ more H+ ions than a solution with a pH of 12.a. 1 b. 4 c. 104 d. 10,000

______9. Which solution contains more OH- ions?a. pH 8.2 b. pH 8.3

10. If we mixed KCl (a common salt) with pure water, do you predict the resulting solution would have a pH above, equal to, or below 7? Explain.

32

11. What does the pH scale measure?

12. Label the following solutions as acid, base or neutral.

_________pH 1_________pH 8.9_________pH 14_________pH 3.2_________pH 7

13. Why is pure water neutral?

14. On the pH scale below, label the arrows on either side of "Neutral" to indicate which direction is increasingly acidic and which is increasingly basic.

15. Name any two solutions that have more H+ ions than OH– ions.

16. Name any two solutions that have more OH– ions than H+ ions.

33