AP Bio CH.8
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
It is lost to the environment.
What shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein?
+^H,-^S,+^G
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?
-20 kcal/mol.
What is an example of potential rather than kinetic energy?
A food molecule made up of energy-rich macromolecules.
A series of enzymes catalyze the reaction X→Y→→Z→A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. What is substance X?
A substrate.
Which of the following types of reactions would decrease the entropy within a cell? A. Dehydration reaction, B. Hydrolysis, C. Respiration, D. Digestion, E. Catabolism.
A. Dehydration reactions.
A series of enzymes catalyze the reaction X→Y→→Z→A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. Substance A functions as
An allosteric inhibitor.
What is something that is considered an open system?
An organism.
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?
As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth.
Sucrose is a disaccharide, composed of the monsaccharides glucose and fructose. The hydrolysis of sucrose by the enzyme sucrase results in
Breaking the bond between glucose and fructose and forming new bonds from the atoms of water.
How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?
By changing the shape of an enzyme.
What term most precisely describes the cellular process of braking down large molecules into smaller ones?
Catabolism.
When you have a severe fever, what may be a grave consequence if this is not controlled?
Change in the folding of enzymes.
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.
Increasing the substrate concentration in an enzymatic reaction could overcome what?
Competitive inhibition.
What is a statement of the first law of thermodynamics?
Energy can't be created or destroyed.
What term is used to describe the transfer of free energy from catabolic pathways to anabolic pathways?
Energy coupling.
The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is known as
Feedback inhibition.
Why is ATP an important molecule in metabolism?
It provides energy coupling between exergonic and endergonic reactions.
A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because
The activation energy barrier for this reaction cannot be surmounted.
According to the induced fit hypothesis of enzyme catalysis, what is a true statement?
The binding of the substrate changes the shape of the enzyme's active site.
For living organisms, what is an important consequence of the first law of thermodynamics?
The organism ultimately must obtain all of the necessary energy for life from its environment.
What is a true statement about enzyme-catalyzed reactions?
The reaction is faster than the same reaction in the absence of the enzyme.
What is true for all exergonic reactions?
The reaction proceeds with a net release of free energy.
What is true for anabolic pathways?
They consume energy to build up polymers from monomers.
An important group of peripheral membrane proteins are enzymes, such as the phospholipases that attack the head groups of phospholipids leading to the degradation of damaged membranes. What properties must these enzymes exhibit?
Water solubility.
The mathematical expression for the change in free energy of a system is ^G=^H-T^S. What is correct about this?
^G is the change in free energy.
A chemical reaction that has a positive G is correctly described as
Endergonic.
