60 Marks

1. Lysosomes are associated with

a. protein synthesis
b. polysaccharide synthesis
c. glycolysis
d. intracellular digestion
 
2. Organelles in a cell which have a double membrane include

a. nucleus, lysosome, and ribosomes
b. endoplasmic reticulum, golgi body and ribosomes
c. nucleus, mitochondria and chloroplasts
d. endoplasmic reticulum, nucleus and mitochondria
 
3. Some cells were observed under a microscope as they responded to a coloured dye placed in the surrounding water. Only small amounts of dye entered living cells. A lot of dye entered and remained in any cells that were dead. The best interpretation of these observations is that cells

a. take in dye by active transport, and then lose it by passive transport
b. take in dye by passive transport, and remove it rapidly by active transport
c. take in dye by active transport, and remove it rapidly by active transport
d. take in dye by passive transport, and lose it by passive transport
e. take in dye by diffusion, and retain it by active transport
 
4. Which of the following substances would move most readily through a cell membrane?

a. a lipophobic substance
b. a lipophilic substance
c. an ionized substance
d. a protein
e. a hydrophillic substance
 
5. All the following are true of the plasma membrane except:

a. The plasma membrane forms a boundary between the cytoplasm and the external environment.
b. Cells are capable of communication because of the nature of the plasma membrane.
c. Regulation of materials moving into an out cell is accomplished by the plasma membrane.
d. The outermost structure of all eukaryotic cells is the plasma membrane.
 
6. Protein channels that provide passage for hormones and nutrients between plant cells are termed:

a. Desmosomes
b. Tight junctions
c. Gap junctions
d. Plasmodesmata
e. Intrinsic proteins
 
7.  During catabolism, energy is

a. stored
b. gained
c. released
d. destroyed
e. none of the above
 
8. When fats are used as fuel, the glycerol portion of the molecule enters the glycolytic pathway when converted to

a. phosphoglyceraldehyde
b. phosphoenolpyruvate
c. coenzyme A
d. fructose phosphate
e. pyruvate
 
9. Certain kinds of carbon compounds have a carboxylic acid group (COOH) held in such a manner that it can split off from the rest of the molecule. This process is called

a. decarboxylation
b. oxidation
c. phosphorylation
d. reduction
e. dephosphorylation
 
10. When you are exercising vigorously, your muscle cells are unable to obtain oxygen from your blood at a sufficient rate. As a result, the muscle cells

a. stop functioning, resulting in cramps.
b. activate anaerobic metabolism, producing lactic acid and releasing energy.
c. get their energy from oxidative phosphorylation instead
d. use a 4 carbon system as an external source of energy
e. use lactic acid to synthesize glycogen for the glycolytic pathway
 
11. When glucose burns in air, it releases heat rapidly. In the cellular respiration of glucose

a. no heat is released
b. no oxygen is required
c. water prevents uncontrolled combustion
d. enzymes make the reaction take place in small steps
e. all of the energy is converted into ATP
 
12. The first step in the activation of glucose for respiration is

a. removal of a molecule of water
b. addition of a hydrogen ion
c. removal of an atom of oxygen
d. addition of a phosphate group
e. addition of an atom of oxygen
 
13. The following molecules occur at different stages of the release of energy during cellular respiration:
I acetyl co-enzyme a
II carbon dioxide
III glucose
IV fructose phosphate
V pyruvate
In which of the following are the above molecules arranged in order from the greatest to the least chemical energy?
a. IV, III, V, I, II
b. III, I, V, IV, II
c. III, IV, I, V, II
d. III, IV, V, I, II
e. II, I, V, IV, III
 
14. In the Krebs cycle, the most frequent electron acceptor is

a. NAD⁺
b. coenzyme A
c. ADP
d. NADH
e. FAD⁺
 
15. The final product of the electron transport chain in cellular respiration is a molecule of

a. water
b. ATP
c. co-enzyme A
d. pyruvate
e. cytochrome oxidase

1. Explain the following terms:

a. Endergonic Reaction
 
 

b. Catabolism
 
 

c. Second Law of Thermodynamics
 
 
 

d. Facilitated Diffusion
 
 
 

e. Tight Junctions
 
 

2. a. Draw and Label a diagram of the cell membrane.
 
 
 
 
 
 
 
 
 
 

2 b. What name is given to this model?
 
 

3. a. With the aid of a diagram, explain endocytosis.
 
 
 
 
 
 
 
 
 
    b. What feature of the cell makes this process possible?
 
 

    c. Explain the possible role of extrinsic proteins in endocytosis.
 
 
 
 

4. Chemical reactions in the cell are usually coupled. Use an example to explain this statement.
 
 
 
 
 
 
 
 
 
 
 
5. a. What type of reaction is shown in the diagram below?

 
    b. Explain this reaction.
 

6. During the later stages of starvation a person starts to metabolize their proteins.

   a. List in order of preference, food molecules the body would use prior to proteins.
 
 
 
 

Assume the following polypeptide is being metabolized:
 

glycine-alanine-serine-serine-glycine-glycine-alanine
 

Enzymes are available to convert each glycine to acetyl-CoA, and serine to citric acid in the Krebs cycle(or citric acid cycle), and alanine to pyruvate.
 

   b. How many ATP molecules would be produced as a result of the metabolism of the above polypeptide? (Show your work)
 
 
 
 
 
 

  c. Where, exactly, is most of the ATP produced?
 
 

  d. Explain the process mentioned in part c. that produces most of the ATP.