Respiration in Cells (chapter 7)

Anaerobic - without oxygen

Aerobic - with oxygen

Fermentation

Cellular Respiration

4 Metabolic Pathways

definition

process of obtaining energy from organic molecules & releasing waste products

breakdown of glucose to produce ATP for energy

  1. Glycolysis (cytosol)
  1. Breakdown of Pyruvate (mitochondrial matrix)

3. Citric Acid Cycle / Krebs Cycle (mitochondria)

  1. Oxidative Phosphorylation (mitochondria)

energy investment phase

cleavage phase

energy liberation phase

2 ATP to breakdown glucose to fructose-6-phosphate

6 carbon molecule to two 3 molecules of glyceraldehyde-3-phosphate (G3P)

Chemical Formula: C6H12O6 + 6O2 → 6CO2 + 6H2O (glucose + oxygen -> carbon dioxide + water)

produces to 2 pyruvates, 2 NADH, 4 ATP

Net Production: 2 ATP, 2 NADH, 2 pyruvates

broken down by pyruvate dehydrogenase

2 CO2 produced but removed

2 Acetyl CoA & 2 NADH produced

Net production: 2 Acetyl CoA, 2 NADH, 2 CO2 (removed)

Acetyl and CoA deattach

Acetyl attach to oxaloacetate to form citrate (aka citric acid)

series of steps release 2 CO2, 1 ATP, 3 NADH, and
1 FADH2 from 1 Acetyl CoA

oxaloacetate is regenerated

usually requires oxygen

Electron transport chain

releases high energy electrons

Phosphorylation by ATP synthase via Chemiosmosis

FADH2 --> FAD+ + 2 H+

NADH --> NAD+ + H+

increase H+ gradient conc.

energy from H+ gradient phosphorylate ADP + Pi

30 - 34 ATP produced per glucose

Net production: 2 ATP, 6 NADH, 2 FADH2, 4 CO2 (removed)

Net production: 30 - 34 ATP

other molecules can also be used

carbohydrates ---> sugars

proteins ---> amino acids

fats ---> glycerol & fatty acids

two strategies

different final acceptor (not oxygen) in electron transport chain


substrate-level phosphorylation (glycolysis)

Nitrate (E.coli)

lactate (muscle cells)

ethanol (yeast cells)

generate only 2 ATP