Chapter 9 chemistry

Oxidation

loss of electrons

Reduction

gaining electrons

Reducing agent

Reactant that donates electrons

Oxidizing agent

Reactant that accepts electrons

Cell respiration

a catabolic process (exergonic) that oxidizes glucose and reduces oxygen to form water, doing this makes ATP as a byproducts

NAD+ and FAD

coenzymes that get reduced (NADH and FAHD₂) in order to transfer electrons around the process of cell resp.

NAD+

accepts 2 electrons and 1 hydrogen (other H is released into surroundings) functions in glycolysis and Citric acid cycle

FAD

accepts 2 electrons and 2 hydrogens, not as abundant as NAD+, functions in the Citric acid cycle

NADH

the oxidized version of NAD+ yields lots of energy (in form of electrons) gives electrons to the ETC

ATP synthesis

the creation of ATP from ADP using free energy from flow of H+ with their concentration gradient (exergonic), two ways to do it (Oxidative phosphorylation and Substrate level phosphorylation)

Oxidative phosphorylation

accounts for 90% of ATP synthesis, is powered by redox reactions and takes place during last stage of cell resp (after ETC)

Substrate level phosphorylation

takes place during first two stages of cell resp (glycolysis and Citric acid cycle), is made by a phosphate group being transferred from substrate to ADP (made by enzymes)

1st stage of Cell Resp

glycolysis (sugar splitting) takes place in cytosol (outside mitochondria), doesn’t need oxygen to happen, takes 1 glucose and breaks it down into 2 pyruvate

Net input of glycolysis

1 glucose

2 NAD⁺

2 ADP

Net output of glycolysis

2 pyruvate (3C)

2 net ATP

2 NADH

byproduct: 2 H₂O

2nd stage of Cell Resp

Pyruvate Oxidation (to Acetyl CoA) takes place in mitochondrial matrix, is done by enzymes in three step process: carboxyl group is removed as CO2, 2C sugar is oxidized from acetate and NAD+ is reduced to form NADH, Acetate combines w/ coenzyme A to form acetyl CoA

Net input of pyruvate oxidation

2 pyruvate

2 NAD+

2 Coenzyme A

Net output of pyruvate oxidation

2 acetyl CoA

2 NADH

2 CO₂

3rd stage of Cell Resp

Citric acid cycle, happens in mitochondrial matrix, completes breakdown (oxidation) of glucose to CO₂, and goes twice around per glucose molecule

Net input of Citric acid cycle (per gluecose) 2turns

2 Acetyl CoA

6 NAD+

2 FAD

2 ADP

Net output of citric acid cycle (per glucose) 2turns

4 CO₂

6 NADH

2 FADH₂

2 ATP

4th stage of Cell Resp

Oxidation Phosphorylation, happens in inner membrane, 2 main steps (ETC and chemiosmosis), produced most ATP, e- carriers donate to proteins to power the push of H+ against concentration gradient so they can then come back in w/ their concentration gradient through ATP synthase and produce ATP

Net input of oxidation phosphorylation

10 NADH

2 FADH₂

O₂ (end of ETC)

ADP

Net output of oxidation phosphorylation

ATP!!!

H₂O

NAD+

FAD

Chemiosmosis

very last stage of cell resp. flow of ions across membrane down their electrochemical gradient (high to low), helps form ATP during last phase oxidation phosphorylation

Electron transport chain (ETC)

bunch of proteins that are least electronegative to most electronegative (O₂) and electrons fall down the gradient using redox reactions. as e- drop they lose energy which goes into proteins to pump H+ ions against their concentration gradient, water is made when O₂ picks up H+ from solution, no ATP made

ATP synthase

turns ADP into ATP using the flow of H+ ions with their concentration gradient using a knob, smallest motor

__% of glucose is transfered to ATP

34%, the rest is loss as heat

anaerobic

w/o oxygen there is two ways to get ATP, fermentation and anaerobic respiration

anaerobic respiration

carried out by prokaryotic organisms w/o oxygen in environment, glycolysis then ETC (w/ diff final e- acceptor)

Fermentation

produces ATP via substrate level phosphorylation only, glycolysis + reactions that regenerate NAD+, two common types: Alcohol and Lactic acid

Alcohol fermentation

pyruvate is converted to ethanol in two steps: pyruvate decomposes to CO2 and acetaldehyde, Redox reaction reduces acetaldehyde to ethanol and oxidizes NADH. 2 ATPS per glucose and NAD+ is recycled

Lactic Acid fermentation

pyruvate is reduced directly to lactate, 2ATP per glucose, NAD+ is recycled