BIO 212 EXAM 3 (ISU-dobbs/manz)
Questions and All Actual Answers.
If a reaction is exergonic, then which of these statements is true? - Answer The products
have lower Gibbs free energy than the reactants
What is a transition state? - Answer the intermediate complex formed as covalent bonds in
the reactants are being broken and re-formed during a reaction
During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a G of -20
kcal/mol. If you double the amount of enzyme in the reaction, what will be the G for the new
reaction? - Answer -20 kcal/mol
If you were to expose glucose to oxygen on your lab bench, why would you not expect to see it
burn as shown in the figure below? - Answer Activation energy is required for the sugar and
oxygen to reach their transition state.
Complete the following sentences about enzyme function: Enzymes speed reaction rates by
______ and lowering activation energy. Activation energies drop because enzymes stabilize
_______. Enzyme specificity is a function of the active site's shape and the chemical properties
of _______ at the active site. - Answer 1. orienting substrates; 2. the transition state; 3. R-
groups
The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the
pathway is most precisely described as _____. - Answer feedback inhibition
Which statement is true for all redox reactions? - Answer They involve the transfer of
electrons.
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? - Answer in or near the active site
The bond that joins two monosaccharides into a disaccharide is a(n) _____. - Answer
glycosidic bond
Humans can digest starch but not cellulose because _____ - Answer humans have enzymes
that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of
cellulose
, A primary function of carbohydrates attached to the glycoproteins and glycolipids of animal cell
membranes is to ________. - Answer mediate cell—cell recognition
Which of the following statements correctly identifies why fermentation alone won't keep cells
alive.? - Answer The oxidation of glucose via cellular respiration has the potential yield of 29
ATP while the oxidation of glucose via fermentation yields only 2 ATP.
Where do all the carbons of glucose end up when glucose is completely oxidized? - Answer
CO2
Glycolysis is active when cellular energy levels are _____; the regulatory enzyme,
phosphofructokinase, is _____ by ATP. - Answer low; inhibited
The energy of electron transport serves to move (translocate) protons to the outer
mitochondrial compartment. How does this help the mitochondrion produce ATP? - Answer
The translocation of protons sets up the electrochemical gradient that drives ATP synthesis in
the mitochondria.
Energy released by the electron transport chain is used to pump H+ into which location in
eukaryotic cells? - Answer mitochondrial intermembrane space
The final electron acceptor of the electron transport chain that functions in aerobic oxidative
phosphorylation is ________ - Answer oxygen
Which of these equations best summarizes photosynthesis? - Answer 6 CO2 + 6 H2O →
C6H12O6 + 6 O2
Where does the Calvin cycle occur? - Answer white space on right
The light reactions of photosynthesis use _____ and produce _____ - Answer water ...
NADPH
Which of these phosphorylates ADP to make ATP? - Answer bottom bulb shape
_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid
compartment. - Answer circle triangle circle
_____ splits water into 1/2 O2, H+, and e- . - Answer big cube
Questions and All Actual Answers.
If a reaction is exergonic, then which of these statements is true? - Answer The products
have lower Gibbs free energy than the reactants
What is a transition state? - Answer the intermediate complex formed as covalent bonds in
the reactants are being broken and re-formed during a reaction
During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a G of -20
kcal/mol. If you double the amount of enzyme in the reaction, what will be the G for the new
reaction? - Answer -20 kcal/mol
If you were to expose glucose to oxygen on your lab bench, why would you not expect to see it
burn as shown in the figure below? - Answer Activation energy is required for the sugar and
oxygen to reach their transition state.
Complete the following sentences about enzyme function: Enzymes speed reaction rates by
______ and lowering activation energy. Activation energies drop because enzymes stabilize
_______. Enzyme specificity is a function of the active site's shape and the chemical properties
of _______ at the active site. - Answer 1. orienting substrates; 2. the transition state; 3. R-
groups
The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the
pathway is most precisely described as _____. - Answer feedback inhibition
Which statement is true for all redox reactions? - Answer They involve the transfer of
electrons.
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? - Answer in or near the active site
The bond that joins two monosaccharides into a disaccharide is a(n) _____. - Answer
glycosidic bond
Humans can digest starch but not cellulose because _____ - Answer humans have enzymes
that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of
cellulose
, A primary function of carbohydrates attached to the glycoproteins and glycolipids of animal cell
membranes is to ________. - Answer mediate cell—cell recognition
Which of the following statements correctly identifies why fermentation alone won't keep cells
alive.? - Answer The oxidation of glucose via cellular respiration has the potential yield of 29
ATP while the oxidation of glucose via fermentation yields only 2 ATP.
Where do all the carbons of glucose end up when glucose is completely oxidized? - Answer
CO2
Glycolysis is active when cellular energy levels are _____; the regulatory enzyme,
phosphofructokinase, is _____ by ATP. - Answer low; inhibited
The energy of electron transport serves to move (translocate) protons to the outer
mitochondrial compartment. How does this help the mitochondrion produce ATP? - Answer
The translocation of protons sets up the electrochemical gradient that drives ATP synthesis in
the mitochondria.
Energy released by the electron transport chain is used to pump H+ into which location in
eukaryotic cells? - Answer mitochondrial intermembrane space
The final electron acceptor of the electron transport chain that functions in aerobic oxidative
phosphorylation is ________ - Answer oxygen
Which of these equations best summarizes photosynthesis? - Answer 6 CO2 + 6 H2O →
C6H12O6 + 6 O2
Where does the Calvin cycle occur? - Answer white space on right
The light reactions of photosynthesis use _____ and produce _____ - Answer water ...
NADPH
Which of these phosphorylates ADP to make ATP? - Answer bottom bulb shape
_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid
compartment. - Answer circle triangle circle
_____ splits water into 1/2 O2, H+, and e- . - Answer big cube
