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Problem 1
Fill in the blanks in this summary map to help you review the key concepts of cellular respiration.
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Problem 2
A biochemist wanted to study how various substances were used in cellular respiration. In one experiment, she allowed a mouse to breathe air containing O₂ 'labeled' by a particular isotope. In the mouse, the labeled oxygen first showed up in
a. ATP
b. NADH
c. CO₂
d. H₂O
Problem 3
In glycolysis, ________ is oxidized and ________ is reduced.
a. NAD+ ... glucose
b. Glucose ... oxygen
c. ATP ... ADP
d. Glucose ... NAD+
Problem 4
Most of the CO₂ from cellular respiration is released during
a. Stage 1: Glycolysis
b. Stage 2: Pyruvate oxidation
c. Stage 2: The citric acid cycle
d. Stage 3: Oxidative phosphorylation
Problem 5
Which of the following is the most immediate source of energy for making most of the ATP in your cells?
a. The transfer of from intermediate substrates to ADP
b. The movement of H⁺ across a membrane down its concentration gradient
c. The splitting of glucose into two molecules of pyruvate
d. Electrons moving through the electron transport chain
Problem 6
Which of the following is a distinction between cellular respiration and fermentation?
a. The transfer of from intermediate substrates to ADP
b. The movement of H+ across a membrane down its concentration gradient
c. The splitting of glucose into two molecules of pyruvate
d. Electrons moving through the electron transport chain
Problem 7
The poison cyanide binds to an electron carrier within the electron transport chain and blocks the movement of electrons. When this happens, glycolysis and the citric acid cycle soon grind to a halt as well. Why do you think these other two stages of cellular respiration stop? (Explain your answer.)
a. They run out of ATP
b. Unused O₂ interferes with cellular respiration
c. They run out of NAD+ and FAD
d. Electrons are no longer available
Problem 8
In which of the following is the first molecule becoming reduced to the second molecule?
a. Pyruvate → acetylCoA
b. Pyruvate → lactate
c. Glucose → pyruvate
d. NADH + H+ →NAD+ + 2H
- Which of the three stages of cellular respiration is considered the most ancient? Explain your answer.
Problem 9
- Compare and contrast fermentation as it occurs in your muscle cells and in yeast cells.
Problem 10
Problem 11
Explain how your body can convert excess carbohydrates in the diet to fats.
Can excess carbohydrates be converted to protein?
What else must be supplied?
Problem 12
An average adult human requires 2,200 kcal of energy per day. Suppose your diet provides an average of 2,300 kcal per day. How many hours per week would you have to walk to burn off the extra calories? Swim? Run? (See Figure 6.4.)
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Problem 13
Your body makes NAD+ and FAD from two B vitamins, niacin and riboflavin. The Recommended Dietary Allowance is 20 mg for niacin and 1.7 mg for riboflavin. These amounts are thousands of times less than the amount of glucose your body needs each day to fuel its energy needs.
Why is the daily requirement for these vitamins so small?
Problem 14
Oxidative phosphorylation involves the flow of both electrons and H+. Explain the roles of these movements in the synthesis of ATP.
Problem 15
In the citric acid cycle, an enzyme oxidizes malate to oxaloacetate, with the production of NADH and the release of H+. You are studying this reaction using a suspension of bean cell mitochondria and a blue dye that loses its color as it takes up H+. You set up reaction mixtures with mitochondria, dye, and three different concentrations of malate (0.1 mg/L, 0.2 mg/L, and 0.3 mg/L).
Which of the following graphs represents the results you would expect, and why?
Problem 16
ATP synthase enzymes are found in the prokaryotic plasma membrane and in the inner membrane of a mitochondrion.
What does this suggest about the evolutionary relationship of this eukaryotic organelle to prokaryotes?
Problem 17
Several studies have found a correlation between the activity levels of brown fat tissue in research participants following exposure to cold and their percentage of body fat. Devise a graph that would present the results from such a study, labeling the axes and drawing a line to show whether the results show a positive or negative correlation between the variables. Propose two hypotheses that could explain these results.
Problem 18
For a short time in the 1930s, some physicians prescribed low doses of a compound called dinitrophenol (DNP) to help patients lose weight. This unsafe method was abandoned after some patients died. DNP uncouples the chemiosmotic machinery by making the inner mitochondrial membrane leaky to H+.
Explain how this drug could cause profuse sweating, weight loss, and possibly death.