Metabolism

Question 1

metabolic pathway

Answer 1

series of enzyme catalyzed reactions

Question 2

two major purpose of metabolism

Answer 2

1) to obtain usable chemical energy form the environment
2) to make specific molecules that cells need to live and grow

Question 3

anabolic pathways

Answer 3

USE energy to build larger molcules (generally reductive)

Question 4

electrons in anabolic pathways

Answer 4

used to make new bonds

Question 5

catabolic pathway

Answer 5

release energy (generally oxidative)

Question 6

electrons in catabolic pathway

Answer 6

removed as bonds are broken

Question 7

Amphibolic pathway

Answer 7

operate in both anabolic and catabolic

Question 8

carbohydrate storage

Answer 8

glycogen

Question 9

fat storage

Answer 9

triacylglycerols

Question 10

carbons in cataboilism

Answer 10

more oxidized (usually)

Question 11

fatty acids oxidation

Answer 11

fatty acids are more reduced then carbohydrates and need more steps to ozidize them

Question 12

Free energy

Answer 12

review symbols

Question 13

What do you need for a reaction to proceed forward

Answer 13

DeltaG^1reaction must be negative (exergonic)

Question 14

Actual Free energy > 0

Answer 14

reaction will not occur (in fowards direction)

Question 15

Actual Free energy < 0

Answer 15

reaction will occur (spontanous)

Question 15

Actual Free energy «0

Answer 15

May be irreversible

Question 15

Actual Free energy appox 0

Answer 15

reaction is reversible

Question 15

free energy close to equilibrium

Answer 15

will be near 0

Question 16

irreversible steps

Answer 16

usually regulated

Question 16

Steady-State (metabolic pathways)

Answer 16

concertration of metaboilic intermediates often do not change drastically (the amount of water going in equals the amount of water going out)

Question 16

Free energy in Pathways

Answer 16

must be less then 0. Nothing happens if it’s not exergonic

Question 17

reversible steps

Answer 17

not usually regulated

Question 18

Rate-limiting step

Answer 18

irreversible regulated reaction that determines the overall rate

Question 19

product inhibition

Answer 19

An enzyme is inhibited by the product of its reaction (A being inhibited by B)

Question 20

feedback inhibition

Answer 20

An enzyme is inhibited by a metabolite further down the pathway (downstream) (A being inhibited by E)

Question 21

Upstream Activation (feed-forward Activation)

Answer 21

A increase E. As A increases B,C,D would want to increase to maintain steady state.

Question 21

reciprocal regulation problem

Answer 21

opposing pathways catalyze the reverse of another pathway (short of like to people moving boxes in separate ways, no net movement but a waste of energy)

Question 22

reciprocal regulation

Answer 22

pathways are regulated to ensure that both do not operate simultaneously.

Question 23

High-energy intermediates

Answer 23

compounds which contain usable chemical energy

Question 23

Three major types of high energy molecules

Answer 23

Electron carriers, nucleoside triphosphates, thioesters

Question 24

Catabolism Ox or Red

Answer 24

Oxidative metabolites are oxidized (lose electrons), cofactors are reduced (oxidizing agents), usually NAD+ and FAD

Question 25

Anabolism Ox or Red

Answer 25

reductive metabolites are reduced (gain electrons), cofactors are oxidized (reducing agents), usually NADPH

Question 26

Nucleotides role in metabolism

Answer 26

electron carriers. The nitrogen base portion of these dinucleotides enables them to undergo a reversible reduction reaction

Question 27

FAD/FADH2 as a prostetic group

Answer 27

FADH2 must be reoxidized back to FAD for next enzyme cycle

Question 28

why is ATP high energy

Answer 28

phosphoanhydide bonds

Question 29

phosphoanyhdride bond

Answer 29

hydrolosis is -32kJ/mol, formation is +32 kJ/mol

Question 30

thioesters

Answer 30

high energy compunds, similar to esters but have no electron delocalization

Question 31

Adenosine triphosphate

Answer 31

energy currency, phophoanhydride bond makes it high energy. generated by catabolism

Question 32

Adenosine triphosphate genrrated by catabolism

Answer 32

direclty as part of enzyme rxn, via reduction of NADH/FADH2

Question 33

Adenosine triphosphate uses

Answer 33

driving unfavourable reactions (coupling), movement (muslces), primary active transport (ion pump).

Question 34

Coupling of free energies

Answer 34

free energy changes for reactions are additive. An unfavourable rxn can occur if a favourable rxn occurs in concert, combined they must be spontaneous.

Question 35

Phosphate transfer potential

Answer 35

free energies of hydrolysis for phosphate-containing compounds