Chapter 3 Vocab

Question 1

free energy, G

Answer 1

energy that can be harnessed to do work, such as drive a chemical reaction.

Question 2

free-energy change, delta G

Answer 2

difference in free energy between the reactants and products.

large - delta G means theres a strong tendency for the reaction to occur,

the free energy change is defined in pressure, concentration, and temp.

Question 3

hydrolisis

Answer 3

chemical reaction involves cleavage of a covalent bond with the accompanying consumption of water (its -H being added to one product of the cleavage and its -OH to the other); the reverse of condensation

Question 4

Km

Answer 4

the concentration of a substrate at which an enzyme works at half its maximum rate. large values of Km usually indicate that the enzyme binds to its substrate with relatively low affinity

Question 5

metabolism

Answer 5

the sum of total chemical reactions that take place in the cells of a living organism

Question 6

Michaelis constant (Km)

Answer 6

concentrat of an substrate at which an enzyme works at half its maximum velocity.
serves as a measure of how tightly the substrate is bound

Question 7

NAD+(Nicotine Adenine dinucleotide)

Answer 7

active carrier that accepts a hydride ion from a donor molecule producing NADH.

widely used in the energy-producing breakdown of sugar molecules (figure 3-34)

Question 8

NADH

Answer 8

active carrier. widely used in the energy-producing breakdown of sugar molecules (figure 3-34)

Question 9

NADPH (Nicotine Adenine dinucleotide phosphate)

Answer 9

active carrier closely related to NADH and used as an electron donor in biosynthetic pathways. in the process it is oxidized to NADP+

Question 10

oxidation

Answer 10

removal of electrons from an atom.

Question 11

photosynthesis

Answer 11

the process by which plants, algae, and some bacteria use the energy of the sunlight to drive the synthesis of organic molecules from carbon dioxide and water

Question 12

reduction

Answer 12

The addition of electrons to an atom

Question 13

respiration

Answer 13

general term for any process in a cell i which the uptake of molecular oxygen (O2) is coupled into the production of CO2

Question 14

substrate

Answer 14

a molecule on which an enzyme attacks

Question 15

turnover number

Answer 15

the number of substrate molecules an enzyme can convert to product per second

Question 16

Vmax

Answer 16

the maximum rate of an enzymatic reaction, reached when the active sites of the enzyme molecules in a sample are fully occupied by substrate

Question 17

acetyl CoA

Answer 17

Activated carrier that donates the carbon atoms in its readily transferable acetyl group to many metabolic reactions, including the citric acid cycle and fatty acid biosynthesis; the acetyl group is linked to coenzyme A (CoA) by a thioesterbond thatreleases a large amount of energy when hydrolyzed.

Question 18

activated carrier

Answer 18

A small molecule that stores energy or chemical groups in a form that can be donated to many different metabolic reactions. Examples include ATP, acetyl CoA, and NADH.

Question 19

activation energy

Answer 19

The energy that must be acquired by a molecule to undergo a chemical reaction.

Question 20

ADP

Answer 20

(adenosine 5’-diphosphate)

Nucleoside diphosphate produced by hydrolysis of the terminal phosphate of ATP.

Question 21

anabolism

Answer 21

Set of metabolic pathways by which large molecules are made from smaller ones.

Question 22

biosynthesis

Answer 22

An enzyme-catalyzed process by which complex molecules are formed from simple substances by living cells; also called anabolism.

Question 23

catabolism

Answer 23

Set of enzyme-catalyzed reactions by which complex molecules are degraded to simpler ones with release of energy; intermediates in these reactions are sometimes called catabolites.

Question 24

catalysis

Answer 24

The acceleration of a chemical reaction brought about by the action of a catalyst; virtually all reactions in a cell require such assistance to occur under conditions present in living organisms

Question 25

catalyst

Answer 25

Substance that accelerates a chemical reaction by lowering its activation energy; enzymes perform this role in cells.

Question 26

condensation reaction

Answer 26

Chemical reaction in which a covalent bond is formed between two molecules as water is expelled; used to build polymers such as proteins, polysaccharides, and nucleic acids

Question 27

coupled reaction

Answer 27

Linked pair of chemical reactions in which free energy released by one reaction serves to drive the other reaction.

Question 28

diffusion

Answer 28

Process by which molecules and small particles move from one location to another by random, thermally driven motion.

Question 29

entropy

Answer 29

Thermodynamic quantity that measures the degree of disorder in a system.

Question 30

enzyme

Answer 30

A protein that catalyzes a specific chemical reaction.

Question 31

equilibrium

Answer 31

State in which the forward and reverse rates of a chemical reaction are equal so that no net chemical change occurs.

Question 32

equilibrium constant, K

Answer 32

For a reversible chemical reaction, the ratio of substrate to product when the rates of the forward and reverse reactions are equal.

Question 33

ATP

Answer 33

(adenosine 5’-triphosphate)

Molecule that serves as the principal carrier of energy in cells; this nucleoside triphosphate is composed of adenine, ribose, and three phosphate groups.