Lecture 1 - Overview of metabolism

Question 1

Ultimate electron acceptor in oxidation

Answer 1

Oxygen

Question 2

Major electron carrier

Answer 2

NAD+

Question 3

Reactive part of NAD+/NADH

Answer 3

Nicotinamide ring

Question 4

Activated electron carriers for fuel oxidation

Answer 4

NAD+ and FAD

Question 5

Activated electron carriers for reductive biosynthesis

Answer 5

NADPH/NADH

Question 6

Activated carrier of two-carbon fragments

Answer 6

CoA

Question 7

How does CoA bind to acyl groups?

Answer 7

thioester bonds

Question 8

Why do activated carriers need catalysts to react efficiently?

Answer 8

Activated carriers are kinetically stable without catalysts

Question 9

6 types of metabolic reactions

Answer 9

1. Oxidation-Reduction
2. Group transfer
3. Hydrolytic
4. Carbon bond cleavage by means other than hydrolysis or oxidation
5. Isomerization
6. Ligation requiring ATP cleavage

Question 10

Purpose of oxidation-reduction reactions

Answer 10

Useful energy can be derived from oxidation of carbon compounds

Question 11

Purposes group transfer reactions

Answer 11

Synthesise ATP and regulate signalling pathways

Question 12

Purpose hydrolytic reactions

Answer 12

Degrading large molecule by cleaving bonds with water

Question 13

Purpose carbon bond cleavage by means other than hydrolysis or oxidation reactions

Answer 13

Forming double bonds by releasing CO2 or H2O

Question 14

Purpose isomerization reactions

Answer 14

Prepare molecules for subsequent reactions

Question 15

Purpose requiring ATP cleavage reactions

Answer 15

use free energy from ATP cleavage to form molecules

Question 16

Metabolism can be regulated through control of:

Answer 16

1. amount of enzymes
2. their catalytic activity
3. accessibility of substrates

Question 17

Oxidation is …

Answer 17

loss of electrons

Question 18

Reduction is …

Answer 18

gain of electrons

Question 19

What does oxidation to in terms of energy?

Answer 19

It produces energy

Question 20

What does reduction do in terms of energy?

Answer 20

It is a way of storing energy

Question 21

Keq > 1

Answer 21

favours formation of products

Question 22

Keq < 1

Answer 22

favours formation of reactants

Question 23

Gibbs free energy

Answer 23

total free stored energy of a chemical

Question 24

Exergonic reactions

Answer 24

energetically favourable, spontaneous reaction. Negative change in G

Question 25

Endergonic reactions

Answer 25

Energetically unfavourable, non-spontaneous reaction. positive change in G

Question 26

Standard free energy change

Answer 26

free energy change when all reactants and products are initially present at 1M

Question 27

Catabolism

Answer 27

Breaking down fuel molecules to generate energy

Question 28

Anabolism

Answer 28

Use energy to build complex biomolecules required for life

Question 29

2 characteristics of a metabolic pathway

Answer 29

1. each reaction is specific

2. complete pathway is energetically favourable

Question 30

Substrate level phosphorylation

Answer 30

Pass a phosphate group directly to ADP

Question 31

Activated carriers

Answer 31

Biomolecules that store energy in the form of transferable chemical groups

Question 32

3 types of enzyme regulation

Answer 32

short-term: allosteric inhibitors and activators
long-term: gene and proteases regulation
both: hormones