Chapter 8 - Metabolism

Question 1

metabolism

Answer 1

the totality of an organism’s chemical reactions

Metabolism as a whole manages the material and resources of the cell

Question 2

catabolic pathway

Answer 2

leads to the release of energy by the breakdown of complex molecules to simpler compounds

(ex. breakdown of sugars to release energy)

Question 3

anabolic pathway

Answer 3

consume energy to build complicated molecules from simpler ones

(creation of glucose in plants or amino acids linked together to form muscle protein in response to physical exercise )

Question 4

Energy

Answer 4

the capacity to do work

Question 5

kinetic energy

Answer 5

Anything that’s moving possesses kinetic energy

Question 6

potential energy

Answer 6

stored energy that results from position or structure

Question 7

chemical energy

Answer 7

a form of potential energy that is stored in molecules

The amount of chemical energy a molecule possesses depends on its number of bonds

Question 8

Thermodynamics

Answer 8

The study of energy transformations that occur in matter

Question 9

The first law of thermodynamics

Answer 9

the energy of the universe is constant and can be transferred. It cannot, however, be created or destroyed.

Question 10

The second law of thermodynamics

Answer 10

every energy transfer or transformation increases the entropy, or the amount of disorder or randomness in the universe

Question 11

What does the free energy change of a reaction tell us?

Answer 11

Whether or not the reaction occurs spontaneously

Question 12

Free energy

Answer 12

defined as the part of a system’s energy that is able to perform work when the temperature of a system is uniform

Question 13

exergonic reaction

Answer 13

energy is released. Spontaneous (not necessarily mean quickly) and release free energy to the system

Question 14

endergonic reaction

Answer 14

One that requires energy in order to proceed.

Endergonic reactions absorb free energy; that is, they require free energy from the system

Question 15

Energy coupling

Answer 15

the use of an exergonic process to drive an endergonic one

Question 16

Primary source for energy in cells in energy coupling:

Answer 16

ATP

Made of from the nitrogenous base Adenine bonded to ribose and a chain of three phosphate groups

When a phosphate group is hydrolyzed, energy is released in an exergonic reaction

Question 17

ATP becomes what when one phosphate group is hydrolyzed

Answer 17

ADP

Question 18

Enzymes speed up metabolic reactions by

Answer 18

lowering the activation energy

Question 19

what is activation energy

Answer 19

the amount of energy requiems to start a reaction

the amount of energy it takes to break the bonds of the reactant molecules

WITHOUT changing the free energy change of the reaction

Question 20

What is a substrate

Answer 20

The reactant that the enzyme acts on

Question 21

active site

Answer 21

where the enzyme binds to the substrate

Question 22

Enzyme and substrate form a complex called

Answer 22

enzyme-substrate complex

Question 23

What kind of bonds hold together the enzyme-substrate complex

Answer 23

weak bonds such as hydrogen bonds

Question 24

What are the substrates converted into

Answer 24

products which are then released by the enzyme

Question 25

What are the factors that can affect the activity of an enzyme

Answer 25

pH & temperature

changes in the precise shape of an enzyme will usually mean that the enzyme will not be as effective

Question 26

What are cofactor

Answer 26

nonprotein helpers that help the enzyme to function properly. Often include metal ions such as zinc, iron or copper

Question 27

What is an organic cofactor called?

Answer 27

Coenzyme

Question 28

Competitive Inhibitors

Answer 28

Compete with the substrate for the active site

Question 29

Noncompetitive inhibitors

Answer 29

do not directly compete with the substrate molecule but impede with enzyme activity by binding to another part of the enzyme

This causes the enzyme to CHANGE SHAPE and renders the active site nonfunctional

Question 30

allosteric site

Answer 30

Another specific binding site on the enzyme that is not the active site.

Question 31

what binds to the allosteric site

Answer 31

enzyme regulators will bind to the allosteric site, changing its shape. This can either stimulate or inhibit enzyme activity

Question 32

feedback inhibition

Answer 32

the end product of the enzymatic can switch off its pathway by binding to the allosteric site of the enzyme in the pathway

by turning it off when when the product accumulates in the cell it increases the efficiency of the pathway

prevents the enzyme from wasting materials by overproducing

Question 33

open system

Answer 33

energy and matter can be transferred between the system and its surroundings

ORGANISMS ARE OPEN SYSTEMS

Question 34

pH that most enzymes function best at

Answer 34

6-8

Question 35

induced fit

Answer 35

change in the shape of the enzyme at the active site that is induced by the substrate

brings chemical groups at the active site into positions that enhance their ability to catalyze the reaction