Biology 150 Exam 2
release of one G3P to make sugars and regeneration of RuBP
An early step in the process of carbon fixation combines three molecules of CO2 with three molecules of RuBP to produce three 6-carbon molecules, which are immediately converted to six 3-carbon molecules. These six molecules are phosphorylated and reduced to produce glyceraldehyde 3-phosphate (G3P). What additional events occur to complete the Calvin cycle?
is a facultative anaerobe.
An organism is discovered that thrives in both the presence and absence of oxygen. Curiously, the consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organism
They consume energy to synthesize polymers from monomers.
Anabolic pathways share which of the following characteristics?
reduction of acetaldehyde to ethanol
During alcohol fermentation in yeast, NAD+ is regenerated from NADH by which of the following processes?
2
How many carbon atoms from one molecule of pyruvate enter the citric acid cycle?
It is combined with ADP to regenerate ATP.
Hydrolysis of ATP releases energy, which ultimately results in the production of ADP and inorganic phosphate. What generally happens to the inorganic phosphate produced in the cytosol?
the thylakoid space.
If plants are grown in the light with CO2 containing a radioactive isotope of oxygen (18O), subsequent analysis will show that 18O incorporated in organic molecules first appears in
O2
If plants are grown with H2O containing a radioactive isotope of oxygen (18O), subsequent analysis will show that 18O first appears in which of the following molecules produced by the plants?
the Calvin Cycle alone
In C3 photosynthesis, the reactions that require ATP take place in
sucrose
In most plants the carbohydrates produced by photosynthesis are transported out of the leaves to the rest of the plant as which of the following molecules?
both photosynthesis and cellular respiration
In photosynthetic cells, which reactions is (are) responsible for the synthesis of ATP by chemiosmosis?
citric acid cycle →NADH → electron transport chain → oxygen
Inside an active mitochondrion, most electrons follow which of the following pathways?
in or near the active site
Some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquires mutations with amino acid changes that make them resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses?
cyclic electron flow
The Calvin cycle in a culture of algae grown in the light utilizes approximately 30,000 molecules of ATP but only 20,000 molecules of NADPH per hour. What is the source of the extra ATP utilized?
reactions initiated in photosystem I
The NADPH required for the Calvin cycle is produced by which of the following metabolic reactions?
are composed of protein molecules embedded in a fluid bilayer of phospholipids.
The fluid mosaic model of membrane structure suggests that membranes
accepting electrons at the end of the electron transport chain
The oxygen consumed during cellular respiration is involved directly in which process or event?
gene expression
Transcription factors play a major role in regulating which of the following processes?
It is retained in two pyruvate molecules.
Upon completion of glycolysis, what is the fate of the majority of the potential energy contained in the original glucose molecule?
it moves through aquaporin channel proteins.
Water can move quickly through the plasma membrane of some cells because
The sugar molecule is different.
What is the difference (if any) between the structure of ATP and the structure of the A nucleoside triphosphate used to make DNA?
There is no difference; they are the same molecule.
What is the difference (if any) between the structure of ATP and the structure of the A nucleoside triphosphate used to make RNA?
to produce simple sugars from carbon dioxide
What is the primary function of the Calvin cycle?
to serve as an acceptor for electrons and protons, forming water
What is the primary role of oxygen in cellular respiration?
stroma of the chloroplast
Where does the Calvin cycle take place?
2 NADH, 2 pyruvate, and 2 ATP
Which of the following correctly lists all of the energy-containing molecules produced by the catabolism of one molecule of glucose in glycolysis?
a high percentage of unsaturated fatty acids
Which of the following evolutionary adaptations would you expect to find in the cell membranes of Antarctic icefish?
Each electron transfer between carriers results in oxidation of one carrier and reduction of another.
Which of the following is an accurate description of the events that occur along the electron transport chain?
a set of reactions that combine monomers into larger, more energy-rich polymers
Which of the following is an example of an anabolic pathway?
high intracellular concentrations of sodium
Which of the following is required for the sodium-potassium pump to transport potassium ions into an animal cell?
transforming the energy in glucose and related molecules in a chemical form that cells can use for work
Which of the following is the most important result of the process of cellular respiration in biological systems?
movement of sodium ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid
Which of the following membrane activities requires energy from ATP hydrolysis?
oxidative phosphorylation
Which of the following metabolic pathways requires a proton gradient?
an amino acid
Which of the following molecules would you expect to diffuse through the lipid bilayer of a plasma membrane most slowly, if at all?
glucose → glycolysis → pyruvate oxidation → citric acid cycle → electron transport chain
Which of the following sequences represents the correct order in which metabolic reactions occur during the complete oxidation of glucose through aerobic respiration?
NAD+ is reduced to NADH during glycolysis.
Which of the following statements about NAD+ is true?
ATP serves as an energy shuttle in the cell, coupling exergonic and endergonic reactions.
Which of the following statements best describes the critical role that ATP plays in cellular metabolism?
It receives electrons from the electron transport chain associated with thylakoid membranes.
Which of the following statements correctly describes an activity directly associated with photosystem I?
Enzymes generally increase the rate of chemical reactions by lowering activation energy barriers.
Which of the following statements is true of enzymes?
It may alter the tertiary and quaternary structures of cellular enzymes.
Why might a severe fever result in death if it is not brought under control?