STATE UNIVERSITY COLLEGE AT BUFFALO
Department of Biology
Biology 100
Principles of Biology
Spring 2004
Dr. Wadsworth
Mid-Term Exam 2a
Enzymes, Photosynthesis, and Cellular Respiration
Cover Sheet
Name: ____________________________________________________
(Print)
Instructions.
1. Print your name in the space designated on this cover sheet.
2. Be sure that your exam has 9 pages including this cover sheet.
3. Read each question carefully and answer in the space provide
4. At the end of the exam there are 6 short answer questions. Answer only 5 of
these 6 questions. Answering all six questions may reduce your grade.
Under the question you choose not to answer, please write the word "Skip".
Failure to write "SKIP" under the one question you choose not to answer will
reduce your grade.
Multiple Choice
Choose the best answer for the question or the best ending for each statement. Write the letter (A-E) which
corresponds to the best answer on the line before the question. (2 pts each)
_____ 1. Which of the following best illustrates the first law of thermodynamics, the law of conservation of
energy?
a.
b.
c.
d.
e.
Anabolic reactions always release free energy.
The chemical energy of ATP can be converted to mechanical energy by our
muscles.
The high energy electron carrier NAD receives electrons from glucose and delivers
the electrons to oxygen.
Endogonic reactions are spontaneous
Exergonic reactions are spontaneous
_____ 2. A Kilocalorie is a unit of energy. Nutritionists also use this term to describe the energy in food.
One nutritional Calorie, like those described on the back of a bag of potato chips, is the
equivalent to a kilocalorie. (One nutritional Calorie = 1 kilocalorie.) A single potato chip has 20
nutritional Calories. If the energy in the potato chip were used to heat a liter of water, how
much would the temperature of the water rise.
a.
b.
c.
d.
e.
Two tenths of a degree Celsius.
Two degrees Celsius
Twenty degrees Celsius.
Two hundred degrees Celsius.
Two thousand degrees Celsius
_____ 3. Which of the following best describes a spontaneous reaction?
a.
b.
c.
d.
e.
Spontaneous reactions are associated with anabolism
All spontaneous reactions are catalyzed by enzymes
Spontaneous reactions release free energy
Spontaneous reactions do not need enzymes to occur
Spontaneous reactions almost never occur in cells.
_____ 4. The hydrolysis of ATP is one of the main energy releasing reactions in the cell. Specifically to
what does "hydrolysis of ATP" refer?
a.
b.
c.
d.
e.
The catabolism of DNA to nucleotides
The catabolism of ATP to ribose, phosphate and its nitrogenous base
The anabolism of ATP to form ribose, phosphate and its nitrogenous base
The breaking of any chemical bond in ATP
The removal of a phosphate from ATP to form ADP
_____ 5. In an oxidation/reduction reaction the molecule that is oxidized:
a.
b.
c.
d.
e.
loses energy
loses electrons
gains energy
forms hydrogen bonds with oxygen
forms covalent bonds with oxygen
_____ 6. Which of the following would be the best definition of an enzyme?
a.
b.
c.
d.
e.
A protein that adds energy to endogonic reactions to make them spontaneous.
A protein that increases the rate of exergonic reactions
A protein that converts endogonic reactions to spontaneous reactions
A protein that adds activation energy to endogonic reactions
A protein that converts products to substrates
_____ 7. The “Lock and Key Model” is used to describe which of the following characteristics of
enzymes?
a.
b.
c.
d.
e.
Allosteric changes can inactivate enzymes
Substrate Specificity
Enzymes can couple endogonic and exergonic reactions
Enzymes are required for active transport across membranes
Enzymes are proteins made of strings of amino acids
_____ 8. Which of the following best describes the relationship between the ATP/ADP cycle and
metabolism?
a.
b.
c.
d.
e.
Metabolism functions by producing ATP
The ATP/ADP cycle involves oxidation and reduction
ATP creates the energy needed for metabolism
ATP is found in animals and ADP is found in plants
Catabolism produces ATP, Anabolism uses ATP
_____ 9. The enzyme sucrase breaks down table sugar (a disaccharide) to form two monosaccharides
molecules. This is an example of a:
a.
b.
c.
d.
e.
Endothermic reaction
Feedback Inhibition
Catabolic reaction
Enzyme regulation
Substrate inhibition
_____ 10. An ordered sequence of chemical reactions with specific enzymes acting at each step is the
definition of:
a.
b.
c.
d.
e.
High energy electron carrier
Lock and Key Model
Metabolic Pathway
Activation Energy
Intermediary Compounds
_____11. Which of the following is not associated with the reduction of activation energy by enzymes?
a.
b.
c.
d.
Realigning of electrons in covalent bonds
Removing activation energy with NADH
Stressing of chemical bonds
Orienting of substrates to promote the chemical reaction
_____ 12. Lactobacteria are the bacteria that turn milk into yogurt by converting the sugar in milk into
lactic acid. The lactic acid thickens and flavors the milk thus making yogurt. From the
perspective of the bacteria, what is the benefit of this fermentation process?
a.
b.
c.
d.
e.
It provides lactic acid which is necessary for reproduction in bacteria
The lactic acid in the milk is the storage form of energy in bacteria
This process gets rid of the sugar which is poisonous to bacteria
It produces NADPH which is essential to light independent reaction in a dark
refrigerator.
It allows the bacteria to make ATP from milk sugar in the absence of oxygen.
_____ 13. When the cell has high levels of ATP, the ATP binds to an early enzyme of glycolysis, PFK
(phosphofructokinase). The binding of ATP to PFK inactivates the enzyme. This is an
example of which of the following?
a.
b.
c.
d.
e.
Oxidation/Reduction
Fermentation
Feedback Inhibition
Spontaneous Reactions
ATP/ADP Cycle
_____ 14. Where does glycolysis occur in a plant cell?
a.
b.
c.
d.
e.
The central vacuole
The chloroplasts
The cytosol
The inner mitochondrial membrane
The matrix
_____ 15. During cellular respiration, glucose is broken down to carbon dioxide and 38 ATP are generated
from 38 ADP. What is the benefit of this process to cells.
a.
b.
c.
d.
e.
It provides ATP for cellular work
It breaks down the glucose in food
It gets rid of excess ADP
It produces oxygen which is essential to life
It links glycolysis with oxidative phosphorylation
_____16. During fermentation, electrons are removed from NADH so that glycolysis can continue. Which
of the following molecules eventually accepts the electrons from NADH?
a.
b.
c.
d.
e.
Pyruvate
ATP
NAD
Glucose
ADP
_____ 17. During cellular respiration, which of the following processes produce the greatest number of
ATP?
a.
b.
c.
d.
e.
oxidative phosphorylation
Krebs Cycle
Calvin Cycle
Light Independnet Reaction
Glycolysis
_____ 18. What is the direct source of energy used by the ATPase for the synthesis of ATP during
chemiosmosis in the mitochondria?
a.
b.
c.
d.
e.
High energy electrons of NADPH
High energy electrons of NADH
The movement of protons into the matrix
The breakdown of glucose to form carbon dioxide
The hydrolysis of ATP to form ADP and phosphate
_____ 19. Which of the following are substrates for fermentation?
a.
b.
c.
d.
e.
pyruvate and lactate
lactate and ethanol
lactate and ATP
pyruvate and ATP
pyruvate and NADH
_____ 20. What is the important difference between a chemotroph and a phototroph.
a.
b.
c.
d.
e.
Where they get their carbon to make organic molecules
How they break down glucose to make ATP
Whether they require oxygen or not
Where they get their energy to fix carbon dioxide
What their end product of glucose catabolism is.
_____21. During the light reaction, protons are pump into the thylakoid lumen. What is the eventual fate of
these protons?
a.
b.
c.
d.
e.
They move back into the stroma through the ATPase complex
They are excreted by the cell as a waste product
They generate heat by combining with oxygen to form water
They generate ATP by combining with oxygen to form water
They combine with carbon dioxide to make glucose in the calvin cycle
_____ 22. A high school student investigated the growth of bean plants in different colors of light. He
found that after a month of growth, plants in blue light grew better than plants in green light.
What is the best explanation for this difference?
a.
b.
c.
Blue light has more energy than green light.
Blue light but not green light is absorbed by chlorophyll
Green light can only be used for the light reaction, while blue light can power both the
light and the light independent reaction.
Blue light is involved with fluorescence while green light is involved with resonance.
Amateurs shouldn’t grow bean plants
d.
e.
_____ 23. Which of the following is most important for transferring energy from the light reaction of
photosynthesis to the light independent reaction of photosynthesis?
a.
b.
c.
d.
e.
NADH
ATP
Glucose
Carbon dioxide
Oxygen
_____ 24. Rubisco functions during photosynthesis by:
a.
b.
c.
d.
e.
Absorbing blue photons
Catalyzing photolysis
Synthesizing glucose
Utilizing ATP and NADPH
Fixing Carbon Dioxide
_____ 25. Electrons move through the electron transport chain during the light reaction of photosynthesis.
Which of the following best describes where the electrons finally end-up in the Z-scheme of
the light reaction of photosynthesis?
a.
b.
c.
d.
e.
Glucose
Water
Oxygen
ATP
NADP
Short Answer Questions
Answer only five of the following six questions. Under the question you choose not to answer, write
the work "SKIP". (10 pts each)
26. Photosynthesis cycles NADP/NADPH. Explain how this cycling of NADP and NADPH function
during photosynthesis.
27. In most plants the light independent reaction is active only when the light reaction is active. Explain
how the regulation of rubisco contributes the light independent reaction being off in the dark and on in the
light.
28. Describe chemiosmosis and explain how it contributes to ATP production during respiration?
29. An aerobic cell can produce 38 ATP from one glucose molecule. List the metabolic processes that
produce these ATP and list how many ATP are produced by each process.
30. How do the antenna pigments of the photosystem function to contribute energy to the reaction center?
31. Explain how an inhibitor inactivates an enzyme?