18 Integration of Metabolic Pathways Flashcards
1
Q
Are catabolic pathways convergent or divergent?
A
convergent
2
Q
How does catabolism of proteins, fats and carbohydrates converge?
A
- Oxidation of fatty acids, glucose and some amino acids produces acetyl-CoA
- Oxidation of the acetyl groups in TCA cycle
- ATP is produced via oxidative phosphorylation
3
Q
Oxaloacetate can be taken out from the TCA cycle to produce
A
carbohydrates
4
Q
Citrate can be removed from TCA cycle for the biosynthesis of
A
lipids
5
Q
What can be removed from TCA cycle and used for biosynthesis of amino acids?
A
Oxaloacetate and alpha-ketoglutarate
6
Q
TCA cycle intermediates are replenished by what reactions?
A
Anaplerotic reactions
7
Q
How are catabolism and anabolism regulated?
A
- Catabolic and anabolic pathways that connect the same 2 end points may use different enzymes in one of the steps -> site of regulation
- paired catabolic and anabolic pathways can be segregated to different cellular compartments
- conc of intermediates, enzymes and regulators can be maintained at different levels
8
Q
Regulation of metabolic pathways at cellular level
A
- role and mechanism of specific enzymes
- flux of metabolites through pathways
- feedback regulation of metabolic pathways
- transport of metabolites across organelle membranes
9
Q
Regulation of metabolic pathways at whole organism level
A
- metabolic activities of different tissues are reuglated and integrated by growth factors or hormones acting from outside the cells
- flux of metabolites from organs to organs
10
Q
To provide a constant flow of fuel to make ATP, a balance needs to be achieved between
A
- intake of carbohydrate, fat and protein
- rates of oxidation of carbohydrate, fat and protein
- rates of storage when they are in excess of immediate need
11
Q
Is insulin a catabolic or anabolic hormone?
A
anabolic hormone
