Exam 3
Most of the CO2 from the catabolism of glucose is released during _____?
the citric acid cycle
Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration?
30-32
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely
a plant cell in the process of cytokinesis
Select the correct molecule that is the main product of the Calvin cycle.
G3P
Which statement provides the best description of the interphase portion of the cell cycle?
During interphase, a cell is metabolically active.
In mechanism, photophosphorylation is most similar to
oxidative phosphorylation in cellular respiration.
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
H2O → NADPH → Calvin cycle
Following glycolysis and the citric acid cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is in the form of _____.
NADH
In cellular respiration, a series of molecules forming an electron transport chain alternately accepts and then donates electrons. What is the advantage of such an electron transport chain?
The advantage of an electron transport chain is that a small amount of energy is released with the transfer of an electron between each pair of intermediates.
What is true of all cancers?
They have escaped normal cell cycle controls.
Select the most accurate statement describing the basic function of the light reactions of photosynthesis.
The basic function of the light reactions of photosynthesis is the conversion of solar energy to chemical energy.
What is the basic role of CO2 in photosynthesis?
CO2 is fixed or incorporated into organic molecules.
Select the correct statement about cellular respiration.
Cellular respiration and breathing differ in that cellular respiration is at the cellular level, whereas breathing is at the organismal level.
The primary role of oxygen in cellular respiration is to _____
act as an acceptor for electrons and hydrogen, forming water
Where are the proteins of the electron transport chain located?
mitochondrial inner membrane
Which of the following does not occur during the Calvin cycle?
release of oxygen
How is photosynthesis similar in C4 plants and CAM plants?
In both cases, rubisco is not used to fix carbon initially.
Starting with one molecule of glucose, the energy-containing products of glycolysis are _____.
2 NADH, 2 pyruvate, and 2 ATP
A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in
G1
The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of _____.
an endergonic reaction coupled to an exergonic reaction
Which of the following statements accurately describes the function of a metabolic pathway involved in cellular respiration?
The function of glycolysis is to begin catabolism by breaking glucose into two molecules of pyruvate, with a net yield of two ATP.
Which of the following statements is a correct distinction between autotrophs and heterotrophs?
Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.
In chemiosmosis, what is the most direct source of energy that is used to convert ADP + i to ATP?
energy released from movement of protons through ATP synthase, down their electrochemical gradient
Which of the following does not occur during mitosis?
replication of the DNA
If pyruvate oxidation is blocked, what will happen to the levels of oxaloacetate and citric acid in the citric acid cycle shown in the accompanying figure?
Oxaloacetate will accumulate and citric acid will decrease
Why are plants classified as producers?
Plants are classified as producers because they fix inorganic carbon into organic molecules.
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of micro-tubules, its effectiveness must be related to
disruption of mitotic spindle formation.
In the cells of some organisms, mitosis occurs without cytoki-nesis. This will result in
cells with more than one nucleus.
The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin B?
cleavage furrow formation and cytokinesis
The chemiosmotic hypothesis is an important concept in our understanding of cellular metabolism in general because it explains _____.
how ATP is synthesized by a proton motive force
Which electron carrier(s) function in the citric acid cycle?
NADH and FADH2
How will a healthy individual’s ATP production change during an eight-hour fast?
The individual’s ATP production will not change significantly.
The cell cycle control systems of cancer cells differ from those of normal cells. Select the best explanation for this fact.
Genetic changes alter the function of the cancer cell’s protein products.
Select the correct statement about the Calvin cycle
The Calvin cycle has three phases: carbon fixation, reduction, and regeneration of RuBP.
If you were to add one of the eight citric acid cycle intermediates to the culture medium of yeast growing in the laboratory, what do you think would happen to the rates of ATP and carbon dioxide production?
The rates of ATP production and carbon dioxide production would both increase.
Which of the following events takes place in the electron transport chain?
the extraction of energy from high-energy electrons remaining from glycolysis and the citric acid cycle
If a eukaryotic cell is in the G1 phase of the cell cycle, which statement about the cell’s chromosomes must be correct?
Each chromosome is made of a complex of DNA and associated proteins.
Identify all correct statements about the basic function of fermentation.
The basic function of fermentation is the regeneration of NAD+, which allows continued ATP production by glycolysis.
How do cancer cells differ from normal cells?
Cancer cells may be immortal.
Which process is most directly driven by light energy?
removal of electrons from chlorophyll molecules
During aerobic respiration, H2O is formed. Where does the oxygen atom for the formation of the water come from?
molecular oxygen (O2)
The decline of MPF activity at the end of mitosis is due to
the degradation of cyclin.
One difference between cancer cells and normal cells is that cancer cells
continue to divide even when they are tightly packed together.
The light reactions of photosynthesis supply the Calvin cycle with
ATP and NADPH.