Chapter 5 Enzymes, coenzymes & energy

Question 1

acetyl-CoA

Answer 1

The 2-carbon remainder of the carbon skeleton of pyruvic a Hacked to a coenzyme. A molecule acid that is able to enter the mitochondrion for oxidation in the Krebs cycle

Question 2

activation energy

Answer 2

Energy required to start a reaction.

Question 3

active site

Answer 3

The place on the enzyme that causes the substrate to change.

Question 4

adenosine triphosphate (ATP)

Answer 4

blocks of adenine, ribose, and phosphates; it functions as the primary energy carrier in the cell.

Question 5

anabolism

Answer 5

Metabolic pathways that result in the synthesis of new, larger compounds (e.g., protein synthesis).

Question 6

binding site (attachment site)

Answer 6

A specific point on the surface of the enzyme where it can physically attach itself to the substrate.

Question 7

biochemical pathway (metabolic pathway)

Answer 7

A major series of enzyme-controlled reactions linked together.

Question 8

catabolism

Answer 8

Metabolic pathways that result in the breakdown of compounds (e.g., glycolysis).

Question 9

catalyst

Answer 9

A chemical that speeds up a reaction but is not used up in the reaction

Question 10

coenzyme

Answer 10

A molecule that works with an enzyme to enable the enzyme to function as a catalyst.

Question 11

cofactors

Answer 11

Inorganic ions or organic molecules that serve as enzyme helpers.

Question 12

competitive inhibition

Answer 12

No two species can occupy the same niche at the same time.

Question 13

enzymatic competition

Answer 13

Competition among several different available enzymes to combine with a given substrate material.

Question 14

enzyme

Answer 14

Molecules, produced by organisms, that are able to control the rate at which chemical reactions occur.

Question 15

enzyme-substrate complex

Answer 15

A temporary molecule formed when an enzyme attaches itself to a substrate molecule.

Question 16

flavin adenine dinucleotide (FAD)

Answer 16

A hydrogen carrier used in respiration.

Question 17

gene-regulator proteins

Answer 17

Chemical messengers within a cell that inform the genes as to whether protein-producing genes should be turned on or off or whether they should have their protein producing activities increased or decreased (e.g., gene-repressor proteins and gene-activator proteins).

Question 18

high-energy phosphate bond

Answer 18

The bond between two phosphates in an ADP or ATP molecule that readily releases its energy for cellular processes.

Question 19

inhibitor

Answer 19

A molecule that temporarily attaches itself to an enzyme, thereby interfering with the enzyme’s ability to form an enzyme substrate complex.

Question 20

negative-feedback inhibition

Answer 20

A regulatory mechanism in which an increase in the stimulus causes a decrease of the response and results in homeostasis.

Question 21

nicotinamide adenine dinucleotide (NAD+ )

Answer 21

An electron acceptor and hydrogen carrier used in respiration.

Question 22

nutrients

Answer 22

Molecules required by organisms for growth, reproduction, or repair.

Question 23

substrate

Answer 23

A reactant molecule with which the enzyme combines.

Question 24

turnover number

Answer 24

The number of molecules of substrate with which a single molecule of enzyme can react in a given time.

Question 25

vitamins

Answer 25

Organic molecules that cannot be manufactured by the body but are required in very low concentrations for good health.