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Cellular RespirationCellular Respiration

Purpose: create a form of energy useable by the cell

• Neither autotrophs nor heterotrophs can utilize the energy of the carbohydrate as it is. Both types of organisms must convert the carbohydrate to ATP, the energy currency of the cell, in order to carry out metabolic activity.

•Can be summarized in the following equation:

C6H12O6 + 6O2 6H2O + 6CO2 + ATP

3 Parts3 Parts1. Glycolysis

2. Citric Acid Cycle (Kreb’s Cycle)

3. Electron Transport Chain

GlycolysisGlycolysis� Takes place in cytoplasm (cytosol)

� Starts with glucose, NAD and ADP

� Ends with 2 molecules called pyruvate, NADH, 2 ATP (uses 2 ATP)

� Doesn’t need Oxygen

Kreb’s Cycle (Citric Acid Cycle)Kreb’s Cycle (Citric Acid Cycle)� Takes place in the matrix of mitochondria

� Requires Oxygen

� Starts with pyruvate

� Ends with more NADH, CO2, and FADH2, some ATP

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Electron Transport ChainElectron Transport Chain

� Takes place in inner mitochondrial membrane

� Makes the majority of the ATP (~32)

� Breaks down NADH and FADH2

FermentationFermentation

� Occurs in the absence of Oxygen

� Takes place in the cytoplasm (cytosol)

� 2 types:◦ Alcohol Fermentation

◦ Lactic Acid Fermentation

� Goal: Reduce pyruvate made during glycolysis; produces NAD+

� NAD+ can then go back to glycolysis to produce ATP

FermentationFermentation

Alcohol Fermentation Lactic Acid Fermentation

� Occurs in yeasts and some bacteria

� Product (alcohol) is toxic to the organism

� Occurs in humans and other mammals

� Product (lactic acid) is toxic to mammals

� This is the “burn” felt when exercising

Each molecule of glucose can generate 36-38 molecules of ATP in aerobic respiration but only 2 ATP molecules in respiration without oxygen (through glycolysis and

fermentation).

Fermentation vs. AerobicFermentation vs. Aerobic RespirationRespiration

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Cellular Respiration vs. PhotosynthesisCellular Respiration vs. Photosynthesis

Cellular Respiration Photosynthesis

Purpose of electron

transport:

Pump protons across the membrane to

power ATP synthesis

Pump protons across the

membrane to power ATP synthesis

Organelle(s) involved: Mitochondria Chloroplast

Specific location of

electron transport:

Inner membrane Thylakoid membrane

Main supplier of

electrons:

Glucose (carried by NADH & FADH2) Water

Role of oxygen: Remove electrons from the E.T.C. to

allow electron transport to continue

A bi-product from the splitting of a

water molecule