Metabolism and Enzymes

Question 1

Define metabolism

Answer 1

the total of all chemical reactions done in an organism to store or release energy

Question 2

Define metabolic pathway

Answer 2

begins with a specific molecule and ends with a product and is carried out by enzymes

Question 3

Define catabolic pathways

Answer 3

release energy by breaking down molecules into simpler compounds

Question 4

Define anabolic pathways

Answer 4

use energy to build molecules

Question 5

Give an example of an anabolic pathway

Answer 5

synthesis of protein from amino acids to be used in muscles

Question 6

Thermodynamics is the study of _________ ____________.

Answer 6

energy transformations

Question 7

What is the 1st law of thermodynamics?

Answer 7

energy cannot not by created or destroyed, just transformed

Question 8

What is the 2nd law of thermodynamics?

Answer 8

Every energy transfer increases the entropy (disorder) of the universe and makes things unstable. (energy will seek to get back into a stable form or equilibrium)

Question 9

Define free energy

Answer 9

energy available to do work

Question 10

If ∆G is negative, what happened?

Answer 10

energy was released (becomes more stable)

Question 11

If ∆G is positive, what happened?

Answer 11

energy was stored (becomes less stable)

Question 12

Releasing free energy is known as a ___________ ______

Answer 12

spontaneous change

Question 13

The energy released in a spontaneous change do what?

Answer 13

be harnessed to do work

Question 14

Define endergonic reaction

Answer 14

absorbs free energy from its surroundings and is nonspontaneous. (Anabolic)

Question 15

Define exergonic reaction

Answer 15

proceeds with a net release of free energy and is spontaneous. (Catabolic)

Question 16

Define energy coupling

Answer 16

the use of an exergonic process to drive an endergonic one

Question 17

Most energy coupling in cells is done how?

Answer 17

by ATP

Question 18

ATP is made of what?

Answer 18

ribose (a sugar), adenine (a nitrogenous base), and three phosphate groups.

Question 19

ATP powers cells how?

Answer 19

By breaking off a phosphate group. This lowers free energy and releases energy. (exergonic)

Question 20

The released phosphate in ATP does what?

Answer 20

combines with a reactant to make it unstable.

Question 21

Why is phosphorylation useful?

Answer 21

It is an endergonic reaction which makes the recipient molecule unstable with extra stored energy and able to do work.

Question 22

Name the exergonic process in ATP

Answer 22

Dephosphorylation

Question 23

Name the endergonic process in ATP

Answer 23

Phosphorylation

Question 24

Define phosphorylation

Answer 24

When the released phosphate in ATP combines with a reactant

Question 25

Define catalyst

Answer 25

chemical agent that speeds up a reaction

Question 26

What is a catalytic protein

Answer 26

enzyme

Question 27

Define activation energy

Answer 27

The initial energy needed to start a chemical reaction

Question 28

Define substrate

Answer 28

reactant that an enzyme acts on

Question 29

Define substrate complex

Answer 29

enzyme and substrate together

Question 30

Active site

Answer 30

part of the enzyme the substrate binds to

Question 31

Define induced fit

Answer 31

“lock and key” matching shape of enzyme and substrate

Question 32

The active site can lower an EA barrier by

Answer 32

• Orienting substrates correctly
• Straining substrate bonds
• Providing favorable pH
• Covalently bonding to the substrate

Question 33

nonprotein enzyme helpers

Answer 33

cofactors

Question 34

An organic cofactor

Answer 34

coenzyme

Question 35

Define competitive inhibitors

Answer 35

bind to the active site of an enzyme, competing with the substrate

Question 36

Define noncompetitive inhibitors

Answer 36

bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective

Question 37

Enzyme activity is controlled to regulate __________.

Answer 37

metabolism

Question 38

Define allosteric regulation

Answer 38

occurs when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site.

Question 39

make enzymes inactive

Answer 39

Inhibitors

Question 40

make enzymes active

Answer 40

Activators

Question 41

cooperativity

Answer 41

a form of allosteric regulation where the presence of the substrate makes the enzyme active.

Question 42

feedback inhibition

Answer 42

the end product of a metabolic pathway shuts

down the pathway.

Question 43

ΔS is what?

Answer 43

entropy

Question 44

What is the equation for free energy?

Answer 44

ΔG=ΔH-TΔS

Question 45

ΔH is what?

Answer 45

Enthalpy

Question 46

Define enthalpy

Answer 46

The energy to break or release a bond

Question 47

ΔH

Answer 47

exothermic reaction

Question 48

ΔH>0 means what

Answer 48

endothermic reaction