Energy from Food & Mitochondria Chapters 13 and 14

3 steps of cellular metabolism

controlled oxidation of sugar (where does the free energy go)

• enzymes reduce the activation energy barrier ; so the reaction can occur

• the ezyme catalzes the oxidation of sugar and hte free energy is transferred ot carrier molecules; ATP and NADH

• the total free energy released in controlled oxidation is the same as directly buring

• 

Glycolysis

• 2 ATP molecules initiate

Glucose —> • Fructose 1,6 bisphosphate —> glyceraldehyde 3-phosphate (G3P) —> broken into 2 molecules of pyruvate + 4 ATP + 2 NADH.

• Net gain: 2ATP + 2NADH.

substrate-level phosphorylation -

Involves the transfer of a phosphate group directly from a substrate molecule

where does glycolysis occur

cytosol

Fermentation

• pyruvate is turned into lactate —> accepts the hydrogen —> this restores NAD+ that is consumed in glycolosis

• much less energy is used

pyruvate —> acytel CoA

• imported into the mitochondrial matrix

• pyruvate dehydrogenase —> acytel CoA + CO2 +NADH

Citric Acid cycle (how it starts; why it is a cycle; products?)

• oxaloacetate accepts acetyl CoA

  • oxaloacetate is regenerated (why it is a cycle)

• Acetyl CoA —> 2C is removed and bonds with O2 (from H2O) to form CO2

• GTP, 3 NADH and FADH2 (high energy electron carriers produced)

Fatty acids (what is FADH2 reduced to; whta is produced)

• Fatty acids are a primary energy source (along w/ sugars)

• ezymes remove 2 carbons and produce acetyl CoA + NADH +FADH2 with each turn

• FADH2 is reduced flavin adenine dinucleotide.

why is the fatty acid cycle a cycle

2 carbosn are removed at a time

Gluconeogensis (when does it happen; initated when…is abudant)

• process in which blood glucose is synthesized from small

  non-carbohydrate organic molecules such as lactate, pyruvate, or amino acids.

• require an input of energy,

  whereas glycolysis as a whole is an energetically favorable set of reactions.

• glucose is broken down when energy is running low ; opposite if hter eis sufficient reserves in liver cells

• Glycolosis is activated by AMP, ADP and inorganic phosphate (the byproducts of ATP hydrolysis), and inhibited by ATP, citrate, and fatty acid