WHEEL Biochemistry 70 Total Points

Directions: Choose the best correct answer for each question (2 points each).

1. Which is required by all living things? a. Energy b. Mobility c. Oxygen d. Carbon dioxide

2. A microorganism, which releases water into its environment to regulate its salinity during osmosis, is undergoing a process that is similar to a human being who releases moisture on a hot day. This process that helps keep both the microorganism and the human body fluids in balance is known as—

a. homeostasis. b. cell division. c. heredity. d. mutation.

3. Unlike other animals, mammals can perspire (sweat). The main benefit of perspiring is that it— a. removes extra water from the cells. b. cools the skin with evaporation. c. removes dirt from the surface of the skin. d. relaxes the muscles.

4. Cells are the functional units that make up tissues. Tissues then become the functional units that make up— a. enzymes. b. organs. c. other cells. d. DNA.

5. Blood is considered a tissue because blood— a. flows inside arties and veins. b. is necessary to carry oxygen and nutrients to the cells. c. is pumped from the heart and is carried to the cells through arties. d. is composed of red and white blood cells working and having specific functions.

6. Which group contains the six elements especially important to life?

a. C, H, Fe, O, N, S b. C, H, O, N, P, S c. Ag, H, O, N, P, S d. Fe, H, O, C, P, K

7. Water is a polar molecule because a. it has a charge. b. it does not have a charge. c. it contains two hydrogen elements and one oxygen element. d. it has an unequal distribution of charges.

8. The unique properties of water enable life to exist on Earth. Which of these is a property of pure water? a. Its solid form is more dense than its liquid. b. It has a low heat absorption capacity. c. It is slightly more acidic than air. d. It dissolves many substances.

9. When salt dissolves in water, water is considered to be the a. reactant. b. solution. c. solvent. d. solute.

10. If lakes were to freeze solid during the winter, the organisms in the lake would die. Which of these characteristics of water helps prevent freezing of lakes?

a. Water freezes at 00C. b. Water becomes a solid when it freezes. c. Ice floats when it freezes. d. Ice loses heat when it freezes.

11. Which property of water allows many land-dwelling organisms to maintain body temperature by eliminating excess heat?

a. Water’s ability t o evaporate b. Water’s capacity to dissolve substances c. Water’s movement by capillary action d. Water’s formation of ions in solution

12. Chart A shows how changes in pH cause testing paper to change color. Chart B shows how testing papers reacted

with several experimental substances. Which of these has a pH of about 3? a. Apples b. Beans c. Milk d. Shrimp

Test Paper Results

Chart A

pH Red Litmus Blue Litmus pH Paper

Acid—pH 2

Red

Red

Red

Acid—pH 4

Red

Red

Orange

Acid—pH 6

Red

Red

Yellow

Base—pH 8

Blue

Blue

Green

Base—pH 10

Blue

Blue

Blue

Chart B

Substance Red Litmus Blue Litmus pH Paper

Water

Red

Blue

Yellow-green

Apples

Red

Red

Red-orange

Beans

Red

Red

Yellow

Milk

Red

Blue

Yellow

Shrimp

Red

Blue

Yellow-green

13. A lake has a normal pH of 7. Large amounts of acidic waste were dumped into the lake, changing the pH to 4. What is likely to happen?

a. The fish will be more resistant to disease. b. The spawning rate of fish will increase. c. The productivity of the pond will increase. d. The increased acidity will kill most of the fish.

Fis

h P

op

ula

tio

n

0

20

40

6

0 8

0 1

00

1

20

1

40

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Directions: For each of the macromolecules in questions 14-17, select the most appropriate function for each.

14. Carbohydrate a. structure; stores energy for future use

15. Lipid b. contains genetic information

16. Protein c. structure; serves as enzymes

17. Nucleic Acids d. quick energy

Directions: For each of the macromolecules in questions 18-21, select its correct subunit.

18. Carbohydrate a. amino acids

19. Lipid b. glycerol backbone and three fatty acids

20. Protein c. nucleotide

21. Nucleic Acids d. glucose

22. Enzymes only work with specific substrates because each substrate— a. has a specific activation site for enzyme attachment. b. can only use a specific ionic bond with the enzyme. c. destroys its specific enzyme. d. actively interferes with other substances around it.

23. According to the graph below, addition of the enzyme amylase causes the reaction to— a. slow down. b. speed up. c. give off heat. d. take in heat.

Effect of Amylase Enzyme on Starch Digestion Rate

Rate

of

Dig

es

tio

n (

mL

/min

)

0

10

2

0

3

0

40

50

6

0

7

0

0 20 40 60 80 100

Time (sec)

24. Peroxidase is an enzyme that breaks down hydrogen peroxide in cells. It accomplishes this because of its structure. What part of the enzyme is involved in catalytic activity?

a. Binding pocket b. Pleated sheet c. Active site d. Quaternary structure

25. The graph below shows that— a. more enzymes are present at a higher pH. b. pepsin is less sensitive to pH than trypsin. c. pepsin is less effective at a lower pH than trypsin. d. pH affects the activity rate of enzymes.

Rate

of

En

zym

e A

cti

on

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

With Amylase

Without Amylase

Pepsin Trypsin

26. Use the table below to answer the following questions (6 points total).

pH Values of Some Common Substances

Substance pH

Hydrochloric acid 1.0

Sulfuric acid 1.2

Tomatoes 4.2

Rainwater 6.2

Pure water 7.0

Sea water 8.5

Ammonium chloride 11.1

Sodium hydroxide 13.0

a. What is the strongest acid listed?

b. What is the pH of the weakest base listed?

c. Which substance has a neutral pH?

27. Briefly explain how there are many different types of proteins, but there are only 20 amino acids. (2 points)

28. What are the two factors that influence enzyme activity? How does it affect the enzyme? (4 points)

29. Compare enzyme activity to a lock and key. (2 points)

30. Writing Response: You are an astronaut on Mars and recently discovered an unidentifiable object, how would you

determine if it is living or nonliving? Briefly explain 3 ways. (6 points)