Metabolism & Energy

Anabolism

Building molecules

Catabolism

Breaking down molecules

ATP

Main energy currency

NADH

Electron carrier (catabolic)

NADPH

Electron carrier (anabolic)

Redox Reactions

Electron transfer reactions

Electron Donor

Donates electrons

Electron Acceptor

Accepts electrons

Glycolysis

Breaks glucose into pyruvate

Citric Acid Cycle

Generates NADH and ATP

Electron Transport Chain

Produces ATP via oxidative phosphorylation

Fermentation

Energy production without oxygen

Pentose Phosphate Pathway

Produces NADPH and ribose

Substrate-Level Phosphorylation

ATP generation directly from substrate

Oxidative Phosphorylation

ATP from proton gradient

Reverse Transcription

RNA can be converted into DNA.

RNA Catalysts

RNA molecules can act as enzymes.

Post-Translational Modifications

Modify protein activity after synthesis.

Allosteric Regulation

Binding at non-active site changes activity.

Reaction Coupling

ATP drives unfavorable reactions.

ATP Hydrolysis

ATP → ADP + Pi releases energy.

Chemical Work

Bond formation/breaking.

Mechanical Work

Movement (e.g., muscle).

Transport Work

Moving substances across membranes.

Combustion

Methane oxidation to CO2.

Energy Carriers

ATP, NADH, NADPH.

EMP Pathway

Another name for glycolysis.

PFK Regulation

Activated by ADP, inhibited by ATP.

Committed Step

First regulated step in pathway.

Acetyl-CoA Formation

Pyruvate → Acetyl-CoA + CO2 + NADH.

NADH Energy

~3x ATP energy.

FADH2 Energy

~2x ATP energy.

Entner-Doudoroff Pathway

Alternative glycolysis pathway.

Nitrogen Fixation

Requires ~16 ATP per N2.

Glutamate Dehydrogenase (GDH)

Involved in nitrogen metabolism.

Glutamine Synthetase (GS)

Forms glutamine.

PRPP

Intermediate in nucleotide synthesis.

Fatty Acid Biosynthesis (FAB)

Makes lipids.

Fatty Acid Degradation (FAD)

Breaks down lipids.

β-oxidation

Fatty acid breakdown for energy.