NEW
Font size
WorksheetsBIO 181 Chapter 8
Total questions: 10
Worksheet time: 6mins
Are most chemical reactions in living cells at equilibrium?
yes
no
only the exergonic reactions
all reactions except those powered by ATP hydrolysis
A reaction has a ∆G of –5.6 kcal/mol. Which of the following would most likely be true?
The reaction could be coupled to power an endergonic reaction with a ∆G of +8.8 kcal/mol.
The reaction is nonspontaneous.
To take place, the reaction would need to couple to ATP hydrolysis.
The reaction would result in products with a greater free-energy content than in the initial reactants.
The reaction would proceed by itself but might be very slow.
In the energy diagram, what is the difference between the red and black curves?
The red curve is for a reaction powered by ATP hydrolysis. The black curve occurs at higher temperature.
The red curve is catalyzed by an enzyme. The black curve has a higher activation energy.
Vioxx and other prescription nonsteroidal anti-inflammatory drugs (NSAIDs) are potent inhibitors of the cyclooxygenase-2 (COX-2) enzyme. High substrate concentrations reduce the efficacy of inhibition by these drugs. These drugs are
competitive inhibitors.
allosteric regulators.
prosthetic groups.
feedback inhibitors.
The form of energy that is most often least useful to life is energy in
concentration gradients.
electrical gradients.
differences between distinct forms of molecules.
the form of heat.
A change in the coding region of a gene can lead to a new allele for that gene. Which property of the protein, coded for by this new allele, could be changed as a result?
its affinity for its substrate
the amino acid sequence in it
its ability to be affected by allosteric factors
the pH that is optimal for its activity
All of the above could be altered by mutations.
What would happen to cytoplasmic enzyme activity inside a cell with a normal cytoplasmic pH of 7.2 if you injected a chemical that would change the pH to 4.0?
Little or no change would occur.
Enzymes would probably denature.
Enzymatic activity would decline.
Enzymes would start to add ATP to all reactions.
b and c
Which cellular location might contain many enzymatic activities?
mitochondrion
vacuole
cytoplasm
nucleus
all of the above
A friend tells you that his hamster has reached equilibrium. You
send a sympathy card since the hamster is dead.
congratulate your friend on teaching the hamster a trick.
say that the hamster must produce lots of ATP.
What can cause a reaction to occur spontaneously?
–∆G
–∆S
+∆H
∆T
