Bio Chapter 8 Test

24 July 2022
4.7 (114 reviews)
25 test answers

Unlock all answers in this set

Unlock answers (21)
question
Anabloic pathways___
answer
Consume energy to build up polymers from monomers
question
For living organisms, which of the following is an important consequence of the first law of thermodynamics?
answer
The organism ultimately must obtain all of the necessary energy for life from its environment.
question
Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?
answer
As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth.
question
Most cells cannot harness heat to perform work because _____.
answer
Temperature is usually uniform throughout a cell.
question
Which of the following involves a decrease in entropy?
answer
Condensation reactions
question
Which of the following is a statement of the first law of thermodynamics?
answer
Energy cannot be created or destroyed
question
Which of the following is an example of potential rather than kinetic energy?
answer
A molecule of glucose
question
Which of the following is true of metabolism in its entirety in all organisms?
answer
Metabolism consists of all the energy transformation reactions in an organism.
question
Which of the following statements is a logical consequence of the second law of thermodynamics?
answer
Every chemical reaction must increase the total entropy of the universe.
question
Which of the following statements is representative of the second law of thermodynamics?
answer
Cells require a constant input of energy to maintain their high level of organization.
question
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
answer
catabolism (catabolic pathways)
question
A noncompetitive inhibitor decreases the rate of an enzyme reaction by _____.
answer
changing the shape of the enzyme's active site
question
A number of systems for pumping ions across membranes are powered by ATP. Such ATP-powered pumps are often called ATPases, although they do not often hydrolyze ATP unless they are simultaneously transporting ions. Because small increases in calcium ions in the cytosol can trigger a number of different intracellular reactions, cells keep the cytosolic calcium concentration quite low under normal conditions, using ATP-powered calcium pumps. For example, muscle cells transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR). If a resting muscle cell's cytosol has a free calcium ion concentration of 10-7 while the concentration in the SR is 10-2, then how is the ATPase acting?
answer
ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient.
question
According to the induced fit hypothesis of enzyme catalysis, _____.
answer
the binding of the substrate changes the shape of the enzyme's active site
question
Catabolic pathways _____.
answer
supply energy, primarily in the form of ATP, for the cell's work
question
During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a βˆ†G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the βˆ†G for the new reaction?
answer
-20 kcal/mol
question
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
answer
competitive inhibition
question
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's _____.
answer
activation energy
question
The active site of an enzyme is the region that _____.
answer
is involved in the catalytic reaction of the enzyme
question
The lock-and-key analogy for enzymes applies to the specificity of enzymes _____.
answer
Binding to their substrate
question
When ATP releases some energy, it also releases inorganic phosphate. What happens to the inorganic phosphate in the cell?
answer
It may be used to form a phosphorylated intermediate.
question
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
answer
It is lost to the environment.
question
Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst?
answer
The catalyzed reaction will have the same βˆ†G.
question
You have discovered an enzyme that can catalyze two different chemical reactions. Which of the following is most likely to be correct?
answer
Either the enzyme has two distinct active sites or the reactants involved in the two reactions are very similar in size and shape.
question
Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as _____.
answer
a cofactor necessary for enzyme activity