BIOL 121 EXAM I NAME______________________________

Fall 1999

1. (10 points) Why can flour fall through small openings in mesh in grain mills while water, a much smaller molecule, is retained (i.e., doesn’t fall through)? What are the properties of water that produce this difference?

 

 

 

 

 

2. (12 points)

(a) Name 2 kinds of polysaccharides.

 

 

 

(b) Diagram the general structure of a lipid.

 

 

 

(c) Diagram the general structure of a nucleotide..

 

 

 

 

3. (5 points)

(a) Which statement is true concerning the structure of proteins?
    1. The primary structure is the sequence of amino acids.
    2. Helices and sheets are examples of secondary structure.
    3. Proteins made of two or more polypeptide chains have quaternary structure.
    4. All statements are true
    1. The tertiary structure of a protein refers to the:
    1. sequence of amino acids
    2. presence of helices or sheets
    3. unique three-dimensional folding of the molecule
    4. interactions of a protein with other subunits of enzymes
    5. interaction of a protein with a nucleic acid

4. (10 points)

(a) Exergonic reactions:
    1. release energy
    2. are spontaneous reactions
    3. can be coupled to energonic reactions
    4. All statements are true.
    1. Which of the following statements about reaction rate is NOT true?
    1. Reaction rate is the speed at which the reaction proceeds toward equilibrium.
    2. Reaction rate is governed by the energy barrier between reactions and products.
    3. Enzymes can accelerate the rate of a reaction.
    4. Reaction rates are not sensitive to temperature.
    5. None of these
    1. Activation energy is
    1. energy that must be added to get a reaction started, which is recovered as the reaction proceeds
    2. difference in energy between reactants and products
    3. energy that is lost as heat
    4. free energy
    1. The result of a(n) __________ reaction is that energy is released. Energy must be added for a(n) __________ reaction to proceed.
    1. enzyme catalyzed, non-spontaneous
    2. exergonic, endergonic
    3. endergonic, spontaneous
    4. catalytic, non-catalytic
    1. Which statement about enzyme catalyzed reactions is NOT true?
    1. Enzymes form complexes with their substrates.
    2. Enzymes lower the activation energy for chemical reactions.
    3. Enzymes change the equilibrium point for chemical reactions.
    4. Reactions occur at the "active site" of enzymes, where a precise 3D orientation of amino acids is an important feature of catalysis.

 

5. (10 points)

(a) Describe the mechanism of non-competitive inhibition of an enzyme.

 

 

 

(b) How would you experimentally distinguish between competitive and non- competitive inhibition?

 

 

 

 

6. (10 points) Diagram and label the plasma (cell) membrane, including the arrangement of both lipid and protein molecules.

 

 

 

List any 2 functions of the protein portion.

 

 

 

 

7. (5 points) List any 5 cellular structures common to both plant and animal cells.

 

 

 

 

 

 

 

 

8. (5 points) Starting with

 

Which of the three possible

distributions illustrated to

the right is more likely if
heat is applied to the left side?

__________

9. (10 points)

    1. The specific energy source for the reaction ADP + phosphate ® ATP by the (CF1 Coupling Factor) in thylakoid membranes is:
    1. movement of electrons between photosystem II and photosystem I.
    2. oxidation of water.
    3. oxidation of NADPH.
    4. absorption of photons by chloroplast pigments.
    5. diffusion of H+ through the Coupling Factor.
    1. What three events occur during the light reactions of photosynthesis?
    1. reduction of oxygen, oxidation of NADPH, formation of ATP
    2. oxidation of water, reduction of NADP+, formation of ATP
    3. oxidation of water, reduction of NADP+, hydrolysis of ATP
    4. fixation of carbon dioxide, release of oxygen, synthesis of glucose
    5. release of oxygen, fixation of carbon dioxide, hydrolysis of ATP
    1. An overall result of photosynthesis in plants is the use of electrons from water to reduce:
    1. glucose
    2. carbon dioxide
    3. oxygen
    4. chlorophyll b
    5. NADPH
    1. Which of the following is NOT true of photosystem II?
    1. It is located in thylakoid membranes.
    2. It is involved in the oxidation of water.
    3. It has a special oxidizable chlorophyll, P680.
    4. It has an associated antenna complex for light harvesting activity.
    5. None of these

 

10. (8 points) Briefly contrast "carriers" with "channels".

 

 

 

 

 

 

 

 

11. (10 points) Contrast aerobic respiration and glycolysis in 2 ways:

 

 

 

 

 

 

 

 

 

 

12. (5 points) Why do root cells need or require many more mitochondria than green leaf cells of the same size?

 
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