ch 5: cell respiration and metabolism

where does glycolysis occur?

splitting sugar

in the cytosol

tricarboxylic acid (TCA) cycle

krebs cycle, citric acid cycle

in the mitochondrial matrix

what is oxidative phosphorylation

responsible proteins embedded in the inner mitochondrial membrane

metabolism

reactions in body that involve energy transformation

catabolism or anabolism

catabolism

breakdown of molecules to release energy

anabolism

synthesis of larger molecules from smaller ones

requires energy

primary sources of energy for ATP synthesis

glucose

fatty acids

amino acids

broken down into smaller molecules via catabolism

oxidation reduction reactions (redox)

oxidation reduction reactions in cell involve transfer of hydrogen atoms

H+ contains 1 e-

reduction

when an atom or molecule gains electrons

it is reduced

gaining H+

oxidation

when an atom or molecule loses electrons

it is oxidized

losing H+

glycolysis

breakdown of glucose to release energy

enzymes catalyze reactions

yields 2 ATP for each glucose molecule that enters pathway

can occur in aerobic or anaerobic conditions

glucose

powers ATP synthesis

enters cell -> metabolized for energy

coenzymes

substances that bind with enzyme so that it can catalyze a reaction

anaerobic: lactic acid pathway

anaerobic conditions can occur in periods of high energy demand, mainly in RBCs, heart, and skeletal muscle

during anaerobic respiration...

NADH from glycolysis is oxidized -> results in NAD and lactic acid, increasing acidity in tissue

TCA/Citric Acid Cycle/Krebs Cycle process

1. pyruvic acid leaves cytoplasm, enter interior of mitochondrion (matrix)

2. each pyruvic acid molecule -> 1 acetyl coenzyme (acetyl CoA) + 1 CO2

3. enzymes catalyze reactions

4. acetyl CoA enters citric acid cycle

5. two turns of cycle per glucose molecule (bc 2 pyruvic acids = 2 acetyl CoA)

6. 1 ATP produced each turn = 2 ATP

7. produces large amount of NADH and FADH2 -> donate e- for ATP synthesis

citric acid cycle

pyruvic acid resulting from glycolysis enters mitochondrial matrix where citric acid cycle occurs

after each turn, end products include:

3 NADH + H+

1 FADH2

1 ATP

oxidative phosphorylation

synthesis of ATP via pairing of electron transport system with phosphorylation

(addition of phosphate group, PO3) of ADP

what serves as an electron transport system

proteins in inner mitochondrial membrane serves in order to provide energy

process of electron transport system

1. NADH and FADH2 are oxidized -> NAD and FAD

2. molecules in system are reduced

3. process generates energy, which is used to phosphorylate ADP into ATP

4. oxygen is the final electron acceptor; its reduction results synthesis of water

5. produces 32-36 ATP molecules

process of oxidative phosphorylation

1. H+ is pumped from matrix into membrane

2. results in large H+ gradient (difference) between membrane and cytoplasm

3. H+ diffuses through channel in ATP synthase molecule -> phosphorylation of ADP and oxidation