Lecture 10 : Glycolysis

We kind always want to end up with acetyl CoA

• Glycolysis • TCA Cycle (Kreb’s) • ETC (electron transport chain)

• 0-4 hours • Lipids, glucose, amino acids enter gut • Lipids pass into LIVER, liver packages up triglycerides in adipose tissue, stores fats but some transferred to muscle • Glucose delivered everywhere, primarily to brain • Amino acids to muscle for fuel source

• Stores glucose • Highly branched glucose polymer • 1,4 alpha and 1,6 alpha glycosidic bonds • Stored as GRANULES in cytosol of cells • Lots of them in liver (storage) • Lots in muscle (only for local use, exercise, fasting) • Broken down by glucagon / insulin in phosphorylation cascades

• 4-12 hours • Adipose tissue releases fatty acids back into circulation for fuel • Liver, glycogen is broken down into glucose for BRAIN • If muscle needs it, local glycogen stores broken down to glucose

• 12/20 hours onwards • Adipose fatty acid release accelerated, sent to liver to release energy. • Glucose released from liver via gluconeogenesis, liver also releases ketones (desperate) as energy source, ALL TO BRAIN • Muscle generates lactate, also uses amino acids as energy source in dire times

28-32 Main energy source for body

• Glucose, 6C sugar, split into 2 3C pyruvate molecules • net 2 ATP produced • net 2 NADH produced • Pyruvate mostly (when aerobic respiration) enters TCA cycle after

Note the arrow heads, some reactions are reversible, important in diseases or if we want to reverse reactions and create glucose

Depends on presence of O2. Cori cycle involves lactate, paying off o2 debt.