Biology 11

Cellular Respiration

Occurs in every cell in your body

Converts glucose to ATP (Adenosine triphosphate)

ATP =Energy currency for most cellular

processes

Respiration does NOT equal breathing Cellular Respiration is NOT the same as

breathingBreathing is the movement of gases

between the respiratory membrane of living things and their external environment

Respiration is the process to supply oxygen to the cells of the body

The whole process

Glucose + Oxygen Carbon Dioxide + Water + ATP (energy)

C6H10O6 + 6 O2 6CO2 + 6 H2O + 36 ATP

Aerobic - four steps

Glycolysis Splitting of sugars

Transition ReactionPrepared for further reactions

Krebs Cycle (Citric Acid Cycle)Electron Carrier molecules are loaded

Electron Transport SystemTransforms stored energy in electron

carrier molecules into ATP energy

Step #1 - Glycolysis

Location: Cytoplasm of cell

Literally means “Splitting of Sugars”

One molecule of glucose (C6H10O6) is broken down into two molecules of pyruvate.

Step #1 - Glycolysis

Two phases:Phase 1: Preparatory Phase

○ Costs 2 ATPPhase 2: Payoff Phase

○ Produces 4 ATP○ Produces 2 NADH

Glycolysis produces 2 ATP and 2 NADH

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Step #2 – Transition Reaction Pyruvate is taken into the mitochondria

Carbon Dioxide is lost

Pyruvate attaches to Coenzyme-A to form Acetyl-CoA

Step #3 – The Krebs Cycle Location: The Mitochondrial Matrix (the

jelly part of the mitochondria ) Oxygen strips Hydrogen from

Acetyl Co-A, two at a time. This provides the electrons for the next step

Results in 4 ATP and lots of NADH and FADH2

At the end of the Krebs Cycle, all six carbon from the original glucose molecule have been lost in the form of CO2

Step #4 – The Electron Transport Chain Location: In the Mitochondria

Purpose: To convert the energy stored in NADH and FADH2 to ATP

~ 32 ATP are produced

Step #4-The Electron Transport Chain Like moving down a set of stairs,

releasing more and more energy

Oxygen is needed for the Electron Transport Chain to function.It is the final electron acceptor for aerobic

respirationIt combines with Hydrogen to form water

Overview: Glycolysis Transiton

Reaction

Krebs Cycle Electron

Transport Chain

Reactants

[What

goes in]

Glucose 2 Pyruvate

Coenzyme A

2 Acetyl Co-A

Oxygen

NADH

FADH2

Products

[What

comes out]

2 Pyruvate

2 NADH

Acetyl Co-A

CO2

NADH

FADH2

CO2

H2O

# ATP

produced

2 0 4 ~32

Location of

reaction in cell

Cytoplasm Cytoplasm to

Mitochondrial

Matrix

Mitochondrial

Matrix

Mitrochondrial

Christae

The Overall Purpose

To Convert Glucose to an energy form that can be used by our cells: ATP

Anaerobic Respiration

Cellular Respiration in the Absence of Oxygen

Two major types:Lactic Acid FermentationAlcoholic Fermentation

Lactic Acid Fermentation

Takes place in hard working muscle cells

A form of glycolysis breaks down glucose into lactic acid

Lactic Acid accumulates during strenuous exercise if sufficient energy is not available.

Produces a net of only 2 ATP From glycolysis

Alcoholic Fermentation

Location: cytoplasm of yeast cells

Glucose is broken down to alcohol and CO2

93% of energy from glucose is stored in bonds of alcoholThis is why alcohol is so flammable.