Mod 3: Ch 4-Energy and Metabolism

Question 1

Energy

Answer 1

The capacity to do work.

Question 2

First Law of Thermodynamics

Answer 2

Energy cannot be created or destroyed.

Question 3

Second Law of Thermodynamics

Answer 3

Energy tends to disperse spontaneously.

Question 4

Potential Energy

Answer 4

Energy stored in the arrangement of objects in a system.

Question 5

Reactants

Answer 5

A molecule that enters a chemical reaction and is changed by participating in it.

Question 6

Products

Answer 6

A molecule that is produced by a chemical reaction.

Question 7

Activation Energy

Answer 7

Minimum amount of energy required to start a chemical reaction.

Question 8

Active Site

Answer 8

Pocket in an enzyme where substrates bind and a reaction occurs.

Question 9

Substrate

Answer 9

Of an enzyme, specific molecule that can bind to the enzyme’s active site and be converted to a product. A reactant in an enzyme-mediated reaction.

Question 10

Cofactors

Answer 10

A metal ion or small non-protein organic molecule that associates with an enzyme and is necessary for its function.

Question 11

Coenzymes

Answer 11

An organic cofactor.

Question 12

Phosphorylations

Answer 12

Chemical reaction in which an enzyme attaches a phosphate group to an organic molecule.

Question 13

Metabolic Pathway

Answer 13

A series of enzyme-mediated reactions by which cells build, remodel, or break down an organic molecule.

Question 14

Feedback Inhibition

Answer 14

Of a metabolic pathway, regulatory mechanism in which a reaction product slows or stops a pathway that produces it.

Question 15

Electron Transfer Chains

Answer 15

Series of enzymes and other molecules in a cell membrane that accept and give up electrons in turn, thus releasing the energy of the electrons in steps.

Question 16

Diffusion

Answer 16

The spontaneous spreading of molecules or atoms through a fluid or gas.

Question 17

Hypotonic

Answer 17

Describes a fluid that has a low overall solute concentration relative to another fluid.

Question 18

Hypertonic

Answer 18

Describes a fluid that has high overall solute concentration relative to another fluid.

Question 19

Isotonic

Answer 19

Describes two fluids with identical solute concentrations.

Question 20

Osmosis

Answer 20

Diffusion of water through a selectively permeable membrane.

Question 21

Turgor Pressure

Answer 21

Pressure that a fluid exerts against a structure that contains it.

Question 22

Facilitated Diffusion

Answer 22

Passive transport mechanism in which a solute follows its concentration gradient across a membrane by moving through a transport protein.

Question 23

Passive Transport

Answer 23

Membrane-crossing mechanism that requires no energy input.

Question 24

Active Transport

Answer 24

Energy-requiring mechanism in which a transport protein pumps a solute across a cell membrane against eh solute’s concentration gradient.

Question 25

Exocytosis

Answer 25

Process by which a cell expels a vesicle’s contents to extracellular fluid.

Question 26

Endocytosis

Answer 26

Process by which a cell takes in a small amount of extracellular fluid (as its contents) by the ballooning inward of the plasma membrane.

Question 27

Phagocytosis

Answer 27

“Cell eating”; an endocytic pathway by which a cell engulfs a large particle such as another cell.