Enzymes

• 1)Cellular Respiration
•    –Key pathways: Glycolysis → Krebs Cycle → Electron Transport Chain

• 1)Fermentation
•    –Key pathways: Glycolysis → Fermentation

•Generate ATP

•Form intermediates for biosynthetic reactions

• 1)Oxidative Phosphorylation
• -Oxidation-Reduction Reactions
• -Utilizes the electron transport chain

• 2)Substrate-Level Phosphorylation
• -Chemical reaction transferring a phosphate to ADP

• 3)Photophosphorylation
• -Converts energy from light into ATP

Removal of electrons (e-) or hydrogens

•Addition of electrons (e-) or hydrogens

• Capsule -> Cell wall -> Plasma membrane
• Cytoplasm inside cell
• Ribosomes - round balls
• Nucleoid - contains DNA
• Plasmid - small circular DNA strand

•always occur in pairs: coupled.

•There is an electron donor and electron acceptor which constitute a redox pair.

•Process salvages electrons and their energy

•Released energy can be captured to phosphorylate ADP or another compound.

Starting compound: 1 Glucose

• Ending Compounds: 2 Pyruvic
• Acid 2 ATP, & 2 NADH+H+

Location: Cytoplasm

O2 requirements: None

• Starting compound: Pyruvic acid

• Ending compound: Acetyl CoA

• • Released:
• 1 CO2 & 1 NADH (per molec Pyruvate)

• Function: to make acetyl CoA which enters the krebs cycle

Starting Compound: Acetyl CoA

• Ending Compounds:
• Oxaloacetic acid*, 4 CO2, 6 NADH+H+, 2 FADH2 , & 2 ATP

Function: Generates reduced coenzymes (NADH+H+ & FADH2) & ATP

• Location Prokaryotes: Cytoplasm
• Eukaryotes: Mitochondria

• O2 requirements:
• Aerobic respiration: O2 is the electron acceptor

• Anaerobic respiration: other electron acceptor
• (ex. nitrate, nitrite, sulfate)

• •Function: oxidize reduced coenzymes produced by glycolysis & the Krebs cycle, and produce ATP
•     –Chemiosmosis– mechanism using the electron transport chain that produces ATP
•     –Harvests energy from oxidative phosphorylation reactions

OIL RIG, meaning "oxidation is loss" and "reduction is gain," and LEO says GER, meaning "loss of e- = oxidation" and "gain of e- = reduced

• •Location: cell membrane (in prokaryotes)
•       mitochondrial membrane ( in eukaryotes)

• •Oxygen Requirements:
•     –O2 for aerobic respiration
•     –Nitrate, nitrite, or sulfate for anaerobic respiration

•Starting Compound:  10 NADH+H+& 2 FADH2

• •Ending Compounds: NAD+, FAD, H2O, & ATP
•                                 (for aerobic respiration)

•Types of Reactions:

• 1)Oxidation/Reduction (generates oxidized coenzymes, that can then be re-used, ie.
• recycles coenzymes)

• 2)Chemiosmosis: describes the process where by a proton gradient established across the cell membrane is used to drive ATP synthase which creates ATP
•     –Proton motive force generated as H+ are
• pumped out of the cell

•Chemiosmosis – as the electron transport carriers shuttle electrons, they actively pump hydrogen ions (protons) across the membrane setting up a gradient of hydrogen ions - proton motive force.

• •Function: converts glucose to CO2 + H2O
•                  releases energy (ATP)

• •Overall reaction:
•                  C6H12O6 + 6O2 →6CO2 + 6H2O

•Glycolysis + transition step + krebs cycle + electron transport chain

•Oxygen (O2) is the final electron acceptor

•ATP generated by:

1.Oxidative phosphorylation

2.Substrate phosphorylation

•38 ATP theoretical max.

•Function: regenerates oxidized NAD+ & produces ATP

–Uses organic molecule as the final electron acceptor

• –Only
• 2 ATP per glucose!!!

•Location: cytoplasm

•O2 requirements: none!

•Starting Compound: Pyruvic acid/ Pyruvate

•Ending Compound: Alcohol or Organic Acid

•Net Products: (2 examples)

•   1) Alcoholic fermentation (in yeast, Saccharomyces)
•     pyruvate → ethanol + CO2

• 2) Lactic acid fermentation (in bacteria, Lactobacillus)
•     pyruvate → lactic acid/ lactate

• 1) Oxidation/Reduction generates
• oxidized coenzymes, that can then be re-used, ie. recycles coenzymes

2) Decarboxylation - a carbon from glucose is released as carbon dioxide (CO2)

Substrate Phosphorylation forms ATP by the direct transfer and donation of a phosphoryl (PO3) group to adenosine diphosphate (ADP) from a phosphorylated reactive intermediate