Post Lecture Quizzes Flashcards
In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve? 1) It allows the liver cell to have fewer mitochondria. 2) It increases the surface for oxidative phosphorylation. 3) It allows for an increased rate of glycolysis. 4) It increases the surface for substrate-level phosphorylation. 5) It allows for an increased rate of the citric acid cycle.
It increases the surface for oxidative phosphorylation.
Which catabolic processes may have been used by cells on ancient Earth before free oxygen became available? 1) oxidative phosphorylation only 2) glycolysis and fermentation only 3) glycolysis, pyruvate oxidation, and the citric acid cycle 4) glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation, using an electron acceptor other than oxygen 5) glycolysis and the citric acid cycle only
glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation, using an electron acceptor other than oxygen
A mutation in yeast makes it unable to convert pyruvate to ethanol. How will this mutation affect these yeast cells? 1) The mutant yeast will die because they cannot regenerate NAD+ from NAD. 2) The mutant yeast will be unable to metabolize glucose. 3) The mutant yeast will metabolize only fatty acids. 4) The mutant yeast will grow anaerobically only when given glucose. 5) The mutant yeast will be unable to grow anaerobically.
The mutant yeast will be unable to grow anaerobically.
Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount of ATP in a cell would be expected to A) inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle. B) activate the enzyme and thus slow the rates of glycolysis and the citric acid cycle. C) inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle. D) activate the enzyme and increase the rates of glycolysis and the citric acid cycle. E) inhibit the enzyme and thus increase the rate of glycolysis and the concentration of citrate.
inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle.
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes? A) the splitting of water B) the absorption of light energy by chlorophyll C) the flow of electrons from photosystem II to photosystem I D) the synthesis of ATP E) the reduction of NADP⁺
the synthesis of ATP
If photosynthesizing green algae are provided with CO₂ synthesized with heavy oxygen (¹⁸O), later analysis will show that all but one of the following compounds produced by the algae contain the ¹⁸O label. That one is A) 3-phosphoglycerate. B) glyceraldehyde 3-phosphate (G3P). C) glucose. D) ribulose bisphosphate (RuBP). E) O₂.
O2
In the process of carbon fixation, RuBP attaches a CO₂ to produce a six-carbon molecule, which is then split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle? A) addition of a pair of electrons from NADPH B) inactivation of RuBP carboxylase enzyme C) regeneration of ATP from ADP D) regeneration of RuBP E) regeneration of NADP⁺
D) regeneration of RuBP
Plants photosynthesize only in the light. Plants respire A) in the dark only. B) in the light only. C) both in light and dark. D) never–they get their ATP from photophosphorylation. E) only when excessive light energy induces photorespiration.
C) both in light and dark.
Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and can therefore be assayed to track their incorporation. In a set of experiments, a student—faculty research team used labeled T nucleotides and introduced these into the culture of dividing human cells at specific times.
66) The research team used the setup to study the incorporation of labeled nucleotides into a culture of lymphocytes and found that the lymphocytes incorporated the labeled nucleotide at a significantly higher level after a pathogen was introduced into the culture. They concluded that
A) the presence of the pathogen made the experiment too contaminated to trust the results.
B) their tissue culture methods needed to be relearned.
C) infection causes lymphocytes to divide more rapidly.
D) infection causes cell cultures in general to reproduce more rapidly.
E) infection causes lymphocyte cultures to skip some parts of the cell cycle.
infection causes lymphocytes to divide more rapidly.
In metabolic processes of cell respiration and photosynthesis, prosthetic groups such as heme and iron-sulfur complexes are encountered in components of the electron transport chain. What do they do? A) donate electrons B) act as reducing agents C) act as oxidizing agents D) transport protons within the mitochondria and chloroplasts E) both oxidize and reduce during electron transport
E) both oxidize and reduce during electron transport
What wavelength of light in the figure is most effective in driving photosynthesis?
420NM
44) Why do neurons and some other specialized cells divide infrequently?
A) They no longer have active nuclei.
B) They no longer carry receptors for signal molecules.
C) They have been shunted into G₀.
D) They can no longer bind Cdk to cyclin.
E) They show a drop in MPF concentration.
Why is it difficult to observe individual chromosomes with a light microscope during interphase?
1) Sister chromatids do not pair up until division starts.
2) They have uncoiled to form long, thin strands.
3) They leave the nucleus and are dispersed to other parts of the cell.
4) The spindle must move them to the metaphase plate before they become visible.
5) The DNA has not been replicated yet.
2) They have uncoiled to form long, thin strands.
The MPF protein complex turns itself off by
A) activating a process that destroys cyclin components.
B) activating an enzyme that stimulates cyclin.
C) binding to chromatin.
D) exiting the cell.
E) activating the anaphase-promoting complex.
activating a process that destroys cyclin components.
MPF reaches its threshold concentration at the end of this stage.
III
