Micro Chapter 5

A ribozyme is an enzyme made out of _______

RNA

Enzymatic reactions reach a saturation point when the active sites of all enzymes present are occupied by substrate molecules.

True

The cellular poison cyanide binds to and inhibits cytochrome c oxidase, the fourth complex in the electron transport chain. This often results in cells' death as a result of __________. not being able to produce ATP not being able to move electrons through the electron transport chain not being able to produce a hydrogen ion gradient all of these factors

all of these factors

Fermentation differs from cellular respiration by __________. requiring oxygen in order to proceed producing only CO2 and water as end products using organic molecules as the final electron acceptor producing more molecules of ATP

using organic molecules as the final electron acceptor

ATP is made by substrate-level phosphorylation only during glycolysis.

False

High temperatures break the covalent bonds that give enzymes their characteristic shapes, thereby denaturing them.

False

In feedback inhibition pathways, the end product of the pathway is usually an inhibitor of the last enzyme in the pathway.

False

__________ phosphorylation is the process by which inorganic phosphate is attached to an ADP molecule using the energy produced by redox reactions.

Oxidative

A holoenzyme is a combination of an apoenzyme bound to its particular cofactor.

True

Many vitamins are important for metabolism because they act as __________. ribozymes apoenzymes holoenzymes coenzymes

coenzymes

Sulfanilamide is a drug that interferes with bacterial enzymes in which of the following ways? end-product inhibition feedback inhibition noncompetitive inhibition competitive inhibition

competitive inhibition

NAD+, FAD, and NADP+ are all examples of __________. enzymes precursor metabolites electron carriers cytochromes

electron carriers

All of the following processes are ways that a cell can use a proton gradient EXCEPT __________. ATP production active transport electron transport flagellar motion

electron transport

Organisms that grow best at temperatures above 80°C are called __________

hyperthermophiles

The activation energy of a chemical reaction __________ is eliminated in the presence of an enzyme plus a coenzyme can be achieved by lowering the temperature of a reaction is lower in the presence of an enzyme is the same for all chemical reactions

is lower in the presence of an enzyme

A(n) __________ is a type of enzyme that is capable of rearranging atoms within a molecule.

isomerase

Which of the following does NOT affect the activity of an enzyme? oxygen concentration substrate concentration pH temperature

oxygen concentration

All of the following are associated with the process of glycolysis EXCEPT __________. production of NADPH production of pyruvic acid substrate-level phosphorylation phosphorylation of glucose

production of NADPH

Since most proteins are too large to cross the cytoplasmic membrane, prokaryotes begin protein catabolism by secreting __________ into their environment.

proteases

Biological oxidations often involve which of the following? the gain of an oxygen atom the loss of a hydrogen atom the loss of an oxygen atom the gain of an electron

the loss of a hydrogen atom