Lecture 1 - Overview of metabolism Flashcards
Ultimate electron acceptor in oxidation
Oxygen
Major electron carrier
NAD+
Reactive part of NAD+/NADH
Nicotinamide ring
Activated electron carriers for fuel oxidation
NAD+ and FAD
Activated electron carriers for reductive biosynthesis
NADPH/NADH
Activated carrier of two-carbon fragments
CoA
How does CoA bind to acyl groups?
thioester bonds
Why do activated carriers need catalysts to react efficiently?
Activated carriers are kinetically stable without catalysts
6 types of metabolic reactions
- Oxidation-Reduction
- Group transfer
- Hydrolytic
- Carbon bond cleavage by means other than hydrolysis or oxidation
- Isomerization
- Ligation requiring ATP cleavage
Purpose of oxidation-reduction reactions
Useful energy can be derived from oxidation of carbon compounds
Purposes group transfer reactions
Synthesise ATP and regulate signalling pathways
Purpose hydrolytic reactions
Degrading large molecule by cleaving bonds with water
Purpose carbon bond cleavage by means other than hydrolysis or oxidation reactions
Forming double bonds by releasing CO2 or H2O
Purpose isomerization reactions
Prepare molecules for subsequent reactions
Purpose requiring ATP cleavage reactions
use free energy from ATP cleavage to form molecules
Metabolism can be regulated through control of:
- amount of enzymes
- their catalytic activity
- accessibility of substrates
Oxidation is …
loss of electrons
Reduction is …
gain of electrons
What does oxidation to in terms of energy?
It produces energy
What does reduction do in terms of energy?
It is a way of storing energy
Keq > 1
favours formation of products
Keq < 1
favours formation of reactants
Gibbs free energy
total free stored energy of a chemical
Exergonic reactions
energetically favourable, spontaneous reaction. Negative change in G
