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Biology 200, Autumn 2014
Problem Set Week 5
1. Fill in the blanks: Identify the following seven organic molecules. Choose a letter that
corresponds to one of the eleven names listed below. You may use a letter more than once and
some letters may not be used.
A. Amino Acid
B. Deoxyribose
C. Dipeptide
D. Disaccharide
E. Glucose
F. Glycerol
G. Purine
H. Pyrimidine
I. Ribose
J. Saturated Fatty Acid
K. Unsaturated Fatty Acid
Biology 200, Autumn 2014
2. FILL IN THE BLANKS:
Problem Set Week 5
a. Cells harness the energy stored in the electrons of glucose and oxygen molecules in the
process known as _____________.
b. The final products of this process are _________ , __________, and ____________.
c. ATP is produced in glycolysis by the process of ____________________ phosphorylation.
d. There is an initial investment of energy in the form of __________ during glycolysis.
3. Circle the molecule below in which the carbon is the most oxidized.
H
H
C
H
H
H
C
O
H
H
C
O
OH
4-6 Multiple choice: circle ALL correct answers
4. NADH …
a. contains adenine.
b. transfers electrons directly to oxygen.
c. is an electron carrier.
d. is produced during the Krebs cycle.
5. The oxidation of glucose to CO2 and H2O…
a. is exergonic.
b. takes place entirely in the mitochondria.
c. requires the electron transport chain.
d. generates a pH gradient across the inner mitochondrial membrane in eukaryotes.
e. only occurs in eukaryotes.
6. ATP …
a. contains adenine and ribose.
b. hydrolysis to ADP and Pi is exergonic.
c. is an allosteric inhibitor of an enzyme used in glycolysis.
d. is synthesized in both the cytoplasm and the mitochondria.
7. Name the pathways of respiration that produce ATP by substrate-level phosphorylation.
How much ATP is produced by each of these pathways by substrate-level phosphorylation?
Biology 200, Autumn 2014
Problem Set Week 5
8. During respiration in a eukaryotic cell, the majority of ATP is produced by _____________
phosphorylation. How many moles of ATP are produced in this process (expressed per
mole of glucose)? (Assume 2.5 ATP/NADH in matrix, 1.5 ATP/FADH2 in matrix, and an
NADH FADH2 shuttle from the cytoplasm to the matrix).
9. How many electron pairs are transferred to the electron transport chain for every molecule
of glucose that is converted to CO2 and H2O?
10. Specialized human fat cells use the proton gradient in the mitochondria to generate heat in
addition to making ATP. Half the energy in the proton gradient is diverted to the
production of heat and the rest is used to make ATP. Roughly how many moles of ATP will
be produced per mole of glucose by respiration in these human fat cells?
11. A yeast mutant was isolated that was defective in the linking step.
a. How many moles of ATP would this mutant produce per mole of glucose if glucose was
the source of energy and O2 was available?
b. How many moles of ATP per mole of pyruvate would this mutant produce if pyruvate
was the source of energy?
c. How many moles of ATP per mole of pyruvate would a normal strain produce if
pyruvate was the source of energy?
d. How many moles of ATP per mole of glucose would this mutant produce if glucose was
the source of energy and the cells were grown in the absence of O2?
e. How many moles of ATP per mole glucose would a normal strain produce if glucose was
the source of energy and the cells were grown in the absence of O2?
12. One of the major carbohydrate storage molecule in legumes (beans) is raffinose, a
trisaccharide of a galactose, glucose, and a fructose. Humans do not have the enzyme to
break down raffinose, however, many bacteria do. When humans eat beans, the raffinose
ends up in the large intestine. Normally the bacteria that live in the large intestine never
have the luxury of sugars in their diet – they live a “spartan” lifestyle, subsisting on other,
lower-energy foods.
Using this information, explain why eating beans produces gastric distress in the form of
gas. What would you predict the major component of the gas would be?
Biology 200, Autumn 2014
Problem Set Week 5
13. In order to give you an idea of the potential ATP yield from carbohydrates vs. lipids,
answer the following questions:
A. How many C-C and C-H bonds in glucose (C6H12O6) are oxidized when glucose is
completely oxidized to CO2 and H2O? What is the average yield per bond?
B. Draw the molecular structure of a fatty acid with the following chemical composition:
C10H20O2. How many oxidizable C-C and C-H bonds are there?
C. Assuming the same ratio of ATPs per C-C/C-H bond as with carbohydrates, how many
ATPs would be obtained from the oxidation of a mole of this fat to CO2 and H2O?
D. The molecular weight of glucose is 178. The molecular weight of the fatty acid in B is
182, therefore a mole of each is approximately the same mass. Assume taste is not an
issue. If you were planning a long hiking trip where you have to carry your food supply
for several days, which of these two energy foods would you choose and why? (Note:
your back is already weighted down with your Freeman biology textbook and other
necessities!)
14. The reaction to the right is part of the Krebs cycle. For reference
we'll call the initial carbon intermediate "A" and the second carbon
intermediate "B".
(The entire set of intermediates is shown on the last page)
"A"
a. Is a carbon oxidized in this step? _________
b. Is an enzyme needed to catalyze this reaction? ________
c. Name the two other molecules needed for this reaction to proceed:
_______________
_________________
"B"
d. Name the two other product molecules of this reaction:
_______________
_________________
e. This reaction is highly exergonic. Which of the following is true? (Circle the ONE best
answer)
- All of the energy in the C-C bond broken in "A" is stored in the C~S bond in "B".
- The free energy released in this reaction is stored in one of the products.
- There is more free energy in the three reactants (combined) than in the three products
(combined)
- Oxygen is oxidized in this step to release more free energy.
- All redox reactions are highly exergonic.
FROM THE TEXT: (Freeman, 5e)
Ch. 9: 1-3, 5-7, 11-14, 16
FROM THE TEXT: (Freeman, 4e)
Ch. 9: Test Your Knowledge 2, 6; Test Your Understanding 1, 2, 4, 5, 6; Applying Concepts 1, 2