|
Which of the following statement(s) about biochemical pathways is(are) TRUE?
A) they are very well organized and structured
B) they convert an initial substrate via a series of steps into an end product
C) they can only function for a few runs
D) A and B
E) A, B and C
|
D) A and B
|
|
Consider the biochemical pathway: A – E1 -> B – E2 -> C
Enzyme 1 can utilize
A) only A as substrate.
B) only B as substrate.
C) both A and B as substrates.
D) neither A nor B as substrate.
E) either A or B as substrate, but not both.
|
A) only A as substrate.
|
|
Consider the biochemical pathway: A – E1 -> B – E2 -> C
If Enzyme 2 is inactive, which of the following compounds will accumulate?
A) A only
B) B only
C) C only
D) A and B
E) B and C
|
B) B only
|
|
In a biochemical pathway, the product of the first reaction becomes the substrate in the second reaction.
A) True
B) False
|
True
|
|
All biochemical pathways have the same number of enzymatic reactions.
A) True
B) False
|
False
|
|
A person who sprints for 45 seconds obtains most of their energy from
A) muscle triglycerides.
B) plasma free fatty acids.
C) blood glucose.
D) muscle glycogen.
|
D) muscle glycogen.
|
|
What happens to the amount of muscle glycogen used for energy as exercise continues?
A) it increases
B) it decreases
C) it continues unchanged
D) it is never used
|
B) it decreases
|
|
After 3 hours of exercise what are the main sources of energy?
A) blood glucose and plasma free fatty acids
B) blood glucose and muscle glycogen
C) blood glucose and muscle triglycerides
D) muscle glycogen and muscle triglycerides
|
A) blood glucose and plasma free fatty acids
|
|
What happens to the amount of plasma free fatty acids used for energy as exercise continues?
A) they increase
B) they decrease
C) they continue unchanged
D) they are never used
|
A) they increase
|
|
Where are most plasma free fatty acids obtained from?
A) hydrolysis of blood glucose
B) hydrolysis of muscle triglycerides
C) hydrolysis of stored fat
D) sports beverages
|
C) hydrolysis of stored fat
|
|
Enzymes are
A) lipids.
B) proteins.
C) carbohydrates.
D) nucleic acids.
E) steroids.
|
B) proteins.
|
|
Which of the following binds to the active site of an enzyme?
A) water
B) product
C) substrate
D) any other enzyme
E) none of the above
|
C) substrate
|
|
Which of the following correctly represents the mechanism of enzyme function?
A) S + P -> E-P -> E + P
B) E + P -> E-P -> E-S -> E + S
C) E + P -> E-S -> E-P -> E + P
D) E + S -> E-S -> E-P -> E + P
E) E + S -> E-P -> E-S -> E + S
|
D) E + S -> E-S -> E-P -> E + P
|
|
An enzyme can only bind one reactant at a time.
A) True
B) False
|
B) False
|
|
An enzyme speeds up a chemical reaction in the cell, but can only be used once.
A) True
B) False
|
B) False
|
|
Where is sucrose found in the human body?
A) on the gastric surface
B) in the liver
C) on the microvilli of the small intestine
D) in the pancreas
|
C) on the microvilli of the small intestine
|
|
In simple terms sucrase
A) joins glucose and fructose together to form sucrose.
B) breaks sucrose into glucose and fructose.
C) forms a disaccharide from a monosaccharide.
D) breaks sucrose into hydrogen, oxygen and carbon atoms.
|
B) breaks sucrose into glucose and fructose.
|
|
How does sucrose change the configuration of sucrase?
A) by significant trauma when they collide randomly
B) by changing the pH of the solvent
C) by force when under pressure
D) by binding to the active site
|
D) by binding to the active site
|
|
How often can a sucrase molecule be used to hydrolyze sucrose?
A) once
B) twice
C) many times
D) never
|
C) many times
|
|
Blood sugar refers to what molecule circulating in blood?
A) glucose
B) sucrose
C) fructose
D) sucrase
|
A) glucose
|
|
In feedback inhibition, the inhibitor of the biochemical pathway is typically
A) the substrate of the enzyme inhibited.
B) the product of the enzyme inhibited.
C) a substance that is produced towards the middle of the biochemical pathway.
D) the final product of the biochemical pathway.
E) a product of another biochemical pathway.
|
d
|
|
What does the inhibitor bind to during feedback inhibition?
A) active site of the enzyme being inhibited
B) allosteric site of the enzyme being inhibited
C) both A and B
D) neither A nor B
E) either A or B, depending on the biochemical pathway
|
b
|
|
Consider the biochemical pathway used to synthesize the amino acid proline. A high increase in the level of proline will most likely lead to
A) a decrease in proline production.
B) a further increase in proline production.
C) no change in the rate of proline production.
D) increased breakdown of proline.
E) proline being converted to praline.
|
a
|
|
If the end product of a biochemical pathway becomes available in the environment, it is crucial for the cell to continue making the product.
A) True
B) False
|
false
|
|
A biochemical pathway consists of a specific sequence of enzyme-catalyzed reactions.
A) True
B) False
|
true
|
|
Proton pumps are protein complexes that
A) break down water into hydrogen and oxygen.
B) synthesize water from hydrogen and oxygen.
C) pump protons and electrons through the cell membrane.
D) pump protons from the exterior of the cell to the interior.
E) pump protons from the interior of the cell to the exterior.
|
e
|
|
Synthesis of ATP via a proton gradient is called
A) glycolysis.
B) krebs cycle.
C) chemiosmosis.
D) substrate-level phosphorylation.
E) fermentation.
|
c
|
|
Which of the following is the enzyme used to synthesize ATP?
A) ATP phosphodiesterase
B) ATP hydrolase
C) ATP kinase
D) ATP phosphorylase
E) none of the above
|
e
|
|
The protons are generated during oxidation reactions.
A) True
B) False
|
true
|
|
The membrane is permeable to protons.
A) True
B) False
|
false
|
