Biochemistry 2280A Study Guide - Midterm Guide: Metabolic Pathway, Allosteric Regulation, Anabolism
30 Apr 2018
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Biochemistry 2280 – Midterm
Metabolism & Enzyme Regulation
Explain what a metabolic pathway is, what flux is, and the difference between catabolism and
anabolism
Metabolic pathway:
• coordinated series of reactions, catalyzed by enzymes and designed to make specific
products
• chemical reactions that are occurring in your cell —
• cell is acting on something to make something else, and something
else, etc.
• ex. a 10-step pathway
- net ΔG is negative
- a few reactions where the ΔG is negative, lots that are
neutral
- no reactions that have a positive ΔG
- sometimes, the cell may need a lot of 11, but other times lots of 1
- there are ways to change the flux of the pathway…
Flux:
• rate of conversion of A to E (rate of flow)
• if we increase the activity of the enzyme between 5 and 6 (previous), it could be
increasing it both backwards and forwards
• but if we increased the enzyme at compound 3, which has a large negative ΔG, it
would increase the entire flux of the whole pathway because it’s irreversible
• (all enzymes are reversible and will act in either direction IF the conditions are correct)
• earlier reactions in pathways tend to have larger ΔG, which means they’re more likely
to be regulated
Catabolic:
• breaking down larger molecules into smaller ones
• usually extract energy
• oxidative
• provide energy and reducing power to the cell
Anabolism:
• building larger molecules from smaller ones
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Explain what a metabolic pathway is, what flux is, and the difference between catabolism and anabolism. A few reactions where the g is negative, lots that are neutral. No reactions that have a positive g. Sometimes, the cell may need a lot of 11, but other times lots of 1. There are ways to change the flux of the pathway . Catabolic: breaking down larger molecules into smaller ones, usually extract energy, oxidative, provide energy and reducing power to the cell. Anabolism: building larger molecules from smaller ones, source of electrons needed, consume energy and reducing power. Based on g, differentiate between reversible and irreversible reactions. When g is near zero, these are reversible: relatively small changes in substrate concentration can change the net flow of substrates forward or backward through these reactions. When g is large and negative, it is irreversible. Based on g, predict whether a reaction in a pathway is likely to be regulated.
