BCH210H1 Lecture Notes - Lecture 25: Oxidative Phosphorylation, Allosteric Regulation, Exergonic Process
25 May 2018
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Lecture 25: Introduction to Metabolism
Bioenergetics, Protein/enzymes, and Metabolism
• Breaking things down and re-synthesizing
• Energy rich molecules consumed, broken down in catabolic process, harvest
energy, store as ATP and can be used in anabolic processes (building larger
molecules)
• Once ATP broken down, we regenerate ATP by oxidative phosphorylation and
process starts all over again
• Catabolic are oxidative in nature → produces CO2
Catabolism and Anabolism are Interrelated
• Generally, one will dominate
• Catabolism:
- Oxidative
- Exergonic – release energy
• Anabolism:
- Reductive (NADPH, NADH, FADH2 coenzyme)
- Energonic – input energy
• Amphibolic intermediate – molecule made half way through
and used for structure of larger macromolecules
Roles of Metabolism and Bioenergetics
• Breakdown of fuel compound and release of free energy to generate ATP or other intermediates
• Simple building blocks and high energy intermediates are used to synthesize macromolecules and carry out
cellular function
• Metabolism converts of one molecule into another
• Classifications
- Phototrophs – light energy (plants)
- Chemotrophs – other sources of energy (humans)
- Autotrophs – CO2 as their source of carbon
- Heterotrophs – use other sources of carbon
Pathways and Regulation
• A →E1→ B →E2→ C
Enzyme Regulation
• Substrate or enzyme availability – no substrate or enzyme, pathway cannot be on
• Product inhibition – a later substrate can bind to enzyme to inhibit it
• Modification
- Covalent addition of molecules (modifying enzyme to turn on/off)
- Allosteric regulation – bind another molecule (fastest means of regulating enzyme)
find more resources at oneclass.com
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BCH210H1 Full Course Notes
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Document Summary
Catabolism and anabolism are interrelated: generally, one will dominate, catabolism: Energonic input energy: amphibolic intermediate molecule made half way through and used for structure of larger macromolecules. Chemotrophs other sources of energy (humans) Autotrophs co2 as their source of carbon. Heterotrophs use other sources of carbon. Pathways and regulation: a e1 b e2 c. Enzyme regulation: substrate or enzyme availability no substrate or enzyme, pathway cannot be on, product inhibition a later substrate can bind to enzyme to inhibit it, modification. Covalent addition of molecules (modifying enzyme to turn on/off) Allosteric regulation bind another molecule (fastest means of regulating enzyme: protein expression and folding. Gibs free energy and reactions: s p. If keq" > 1 (more product, less substrate), g " is negative, reaction is exergonic (going forward) If keq" < 1, g " is positive, reaction is endergonic (unfavorable) If keq" = 1, g " is zero, reaction is reversible.
