6 An Introduction to Metabolism Flashcards
The process of cellular respiration, which converts simple sugars such as glucose into CO2 and water, is an example of _____.
a catabolic pathway
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
catabolism
Which of the following is (are) true for anabolic pathways?
They consume energy to build up polymers from monomers.
Which of the following is a statement of the first law of thermodynamics?
Energy cannot be created or destroyed.
Whenever energy is transformed, there is always an increase in the
entropy of the universe.
Which of the following statements is a logical consequence of the second law of thermodynamics?
Every chemical reaction must increase the total entropy of the universe.
In general, enzymes are what kinds of molecules?
proteins
Enzymes work by _____.
Enzymes work by reducing the energy of activation.
Which of the following statements is true concerning catabolic pathways?
They supply energy, primarily in the form of ATP, for the cell’s work.
Enzymes are described as catalysts, which means that they _____.
increase the rate of a reaction without being consumed by the reaction
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction’s
activation energy.
The active site of an enzyme is the region that
is involved in the catalytic reaction of the enzyme.
How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?
by changing the shape of the enzyme’s active site
Allosteric enzyme regulation is usually associated with
an enzyme with more than one subunit.
Which of the following is an example of cooperativity?
a molecule binding at one unit of a tetramer, allowing faster binding at each of the other three
The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as
feedback inhibition
Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity?
localization of enzymes into specific organelles or membranes
Which of the following is true of metabolism in its entirety in all organisms?
A) Metabolism depends on a constant supply of energy from food.
B) Metabolism depends on an organism’s adequate hydration.
C) Metabolism uses all of an organism’s resources.
D) Metabolism consists of all the energy transformation reactions in an organism.
E) Metabolism manages the increase of entropy in an organism.
Metabolism consists of all the energy transformation reactions in an organism.
Why is ATP an important molecule in metabolism?
It provides energy coupling between exergonic and endergonic reactions.
When ATP releases some energy, it also releases inorganic phosphate. What purpose does this serve (if any) in the cell?
The phosphate may be incorporated into any molecule that contains phosphate.
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction’s
activation energy
Induced Fit
The binding of the substrate changes the shape of the enzyme’s active site.
Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n)
cofactor necessary for enzyme activity.
How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?
by changing the shape of the enzyme’s active site
Allosteric enzyme regulation is usually associated with
an enzyme with more than one subunit.
