12 terms

Ch. 8

An Introduction to Metabolism
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
Which of the following is a statement of the first law of thermodynamics?
The entropy of the universe is decreasing.
Kinetic energy is stored energy that results from the specific arrangement of matter.
*Energy cannot be created or destroyed.
The entropy of the universe is constant.
Energy cannot be transferred or transformed.
Which of the following is an example of potential rather than kinetic energy?
the flight of an insect foraging for food
light flashes emitted by a firefly
water rushing over Niagara Falls
*a molecule of glucose
the muscle contractions of a person mowing grass
Which of the following is most similar in structure to ATP?
a DNA nucleotide
an amino acid with three phosphate groups attached
a phospholipid
*an RNA nucleotide
a pentose sugar
Which of the following statements is true concerning catabolic pathways?
They combine molecules into more energy-rich molecules.
They are endergonic.
They build up complex molecules such as protein from simpler compounds.
They are spontaneous and do not need enzyme catalysis.
*They supply energy, primarily in the form of ATP, for the cell's work.
Which of the following statements is true about enzyme-catalyzed reactions?
*The reaction is faster than the same reaction in the absence of the enzyme.
Enzyme-catalyzed reactions require energy to activate the enzyme.
Enzyme-catalyzed reactions release more free energy than noncatalyzed reactions.
The free energy change of the reaction is opposite from the reaction that occurs in the absence of the enzyme.
The reaction always goes in the direction toward chemical equilibrium.
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's?
*activation energy.
endothermic level.
equilibrium point.
free-energy content.
The active site of an enzyme is the region that?
is inhibited by the presence of a coenzyme or a cofactor.
binds noncompetitive inhibitors of the enzyme.
*is involved in the catalytic reaction of the enzyme.
binds allosteric regulators of the enzyme.
The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as?
reversible inhibition.
allosteric inhibition.
metabolic inhibition.
*feedback inhibition.
noncooperative inhibition.
Chemical energy is a form of _____ energy.
In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?
*cellular respiration
Which of these are by-products of cellular respiration?
carbon dioxide and water
*heat, carbon dioxide, and water
glucose, carbon dioxide, and water
ATP and carbon dioxide
ATP, carbon dioxide, and water