AP BIO CHAPTER 8

When glucose monomers are joined together by glycosidic linkages to form a cellulose polymer, the changes in free energy, total energy, and entropy are as follows

++-

Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein?

+-+

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

Which of the following statements describes enzyme cooperativity?

A substrate molecule bound to an active site affects the active site of several subunits.

Which of the following is most similar in structure to ATP?

RNA nucleotide

In order to attach a particular amino acid to the tRNA molecule that will transport it, an enzyme, an aminoacyl-tRNA synthetase, is required, along with ATP. Initially, the enzyme has an active site for ATP and another for the amino acid, but it is not able to attach the tRNA. What must occur in order for the final attachment to occur?

The binding of the first two molecules

what is substance X?

a substrate

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reactionʹs

activation energy

Substance A functions as

an allosteric inhibitor.

FIG 8.2 Which of the following represents the activation energy required for the enzyme-catalyzed reaction?

b

Sucrose is a disaccharide, composed of the monosaccharides 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.

FIG 8.2 Which of the following represents the activation energy required for a noncatalyzed reaction?

c

Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity?

compartmentalization of enzymes into defined organelles

Which curve represents the behavior of an enzyme taken from a bacterium that lives in hot springs at temperatures of 70°C or higher?

curve 3

Which curve was most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid?

curve 4

FIG 8.2 Which of the following represents the difference between the free-energy content of the reaction and the free-energy content of the products?

d

FIG 8.2 Which of the following represents the △G of the reaction?

d

Which of the following types of reactions would decrease the entropy within a cell?

dehydration reactions

A chemical reaction that has a positive △G is correctly described as

endergonic

What term is used to describe the transfer of free energy from catabolic pathways to anabolic pathways?

energy coupling

Whenever energy is transformed, there is always an increase in the

entropy of universe

FIG 8.2 Which of the following terms best describes the reaction?

exergonic

Assume that the reaction has a △G of -5.6 kcal/mol. Which of the following would be true?

increase in entropy (S) and a decrease in the total energy content

The active site of an enzyme is the region that

is involved in the catalytic reaction

FIG 8.2 Which of the following bests describes the reaction?

negative △G, spontaneous

Which curve was most likely generated from an enzyme that requires a cofactor?

not possible

When 10,000 molecules of ATP are hydrolyzed to ADP and Pi in a test tube, about twice as much heat is liberated as when a cell hydrolyzes the same amount of ATP. Which of the following is the best explanation for this observation

reactant and concentration models are not the same

Which of the following statements is (are) true about enzyme-catalyzed reactions?

the reaction is faster

which of the following is true for anabolic pathways?

they consume energy