Chapter Eight

Question 1

What is metabolism?

Answer 1

all of an organisms chemicall reactions

Question 2

What is anabolic metabolism?

Answer 2

small molecules build into larger ones; energy requires

(e.g., photosynthesis)

Question 3

What is catabolic metabolism?

Answer 3

large molecules broken into smaller ones; energy released

(e.g., cellular respiration)

Question 4

What are the 3 main types of energy?

Answer 4

• light (radiation)
• kinetic
• thermal
• potential
• kinetic

Question 5

What is kinetic energy?

Answer 5

energy assosciated with motion

Question 6

What is thermal energy?

Answer 6

kinetic energy assosciated with the random movement of atoms of objects

Question 7

Chemical energy is a type of _______ energy; what is it?

Answer 7

potential energy available for release in a chemical reaction

Question 8

What is potential energy?

Answer 8

stored energy based on an objects location or structure

Question 9

What is the 1st law of thermodynamics?

Answer 9

• total amount of energy in the universe is constant and conserved
• energy is not created or destroyed
• energy can be transferredd or change forms

Question 10

What is the 2nd law of thermodynamics?

Answer 10

• every energy transfer increases entropy (disorder) of the universe; randomness of matter increases
• energy willl always be last from a system as heat in energy transfers or transforms

Question 11

Spontaneous reactions…

Answer 11

• need initial nudge of energy
• proceeds without energy input
• not necessarily fast

Question 12

Non-spontaneous reactions…

Answer 12

• need inital nudge of energy
• needs energy to continue
• slow reactions

Question 13

Change in ____ ______ determines if a reaction is spontaneous or not

Answer 13

free energy

Question 14

What change in free energy results in a spontaneous reaction?

Answer 14

negative ΔG

Question 15

What change in free energy results in a non-spontaneous reaction?

Answer 15

0 or positive ΔG

Question 16

What are exergonic reactions?

Answer 16

spontaneous reactions; energy outward, net release of energy

Question 17

What are endergonic reactions?

Answer 17

• non-spontaneous reactions; energy inward, absorbs free energy from surroundings
• energy reequired

Question 18

What happens to a cell if it has a net change in free energy of 0?

Answer 18

it has reached equilibrium; cell has died

Question 19

What are the 3 kinds of work cells do?

Answer 19

• chemical
• transport
• mechanical

Question 20

What is chemical work?

Answer 20

pushing endergonic reactions that would not occur spontaneously

Question 21

What is transport work?

Answer 21

moving substances against gradients

Question 22

What is mechanical work?

Answer 22

largely motion/ movement

Question 23

What is energy coupling? What molecule is responsible?

Answer 23

using an exergonic reaction to drive an endergonic one; ATP

Question 24

What are the main components of ATP?

Answer 24

• ribose (a sugar)
• nitrogenous base (adenine)
• chain of 3 phosphate groups

Question 25

Why is ATP unstable?

Answer 25

the phosphate groups are easily broken

Question 26

What happens with ATP for cells to do work?

Answer 26

the unstable bond between phosphate groups is broken via hydrolysis to release energy

Question 27

How is ATP regenerated?

Answer 27

with the free energy of other exergonic (catabolic) reactions

Question 28

What is **activation energy**?

Answer 28

energy required to initiate a reaction

Question 29

What do catalysts do to reactions?

Answer 29

lower activation energy

Question 30

_______ are catalysts

Answer 30

enzymes

Question 31

How do enzymes lower activation energy?

Answer 31

- change orientation of substance - substrate stretched to make breaking bondds easier - active site may provide a local micro environment that favors the reaction - amino acids in the active site participate in the reactions, but they are not changed

Question 32

What are cofactors?

Answer 32

helper molecules that assist with the catalytic activity

Question 33

What do inhibitors do?

Answer 33

inhibit or slow enzyme activity

Question 34

What are the 2 types of inhibitors?

Answer 34

- competitive inhibitors: bond with the enzyme and block substrate from reaching the active site (positive) - non-competitive inhibitors: don't compete w/ substrate for active site; bound to other areas of the enzyme and change its shape (negative)

Question 35

We often use negative inhibitors as a means of...?

Answer 35

poisoning other organisms

Question 36

What happens in feedback inhibition?

Answer 36

What sfinal product shuts down the pathway temporarily; prevent wasting resources by making more than is needed

Question 37

What is **allosteric activation and inhibition**?

Answer 37

- polypeptite subunit each with an active site - complex has an active site and inactive shape - activating molecule binds to the complex stabilizing the active form - inhibitors bind to the complex stabilizing the inactive form

Question 38

What is **cooperactivity**?

Answer 38

substrate bound to one active site stabilizes other active sites in their active form