Cellular Respiration

BIOLOGY

What is Cellular Respiration?

• Step-by-step breakdown of high-energy glucose molecules to release energy

• Takes place day and night in all living cells

• Occurs in stages, controlled by enzymes

Where does it occur?

• In the Cell Mitochondrion

• Outer Membrane

• Inner Membrane

Different types of Cellular Respiration

• Aerobic respiration Occurs in the

presence of oxygen When chemically

breaking down glucose completely, this process releases large amounts energy

• Anaerobic respiration Usually occurs

when there is no oxygen available

When partially breaking down glucose, this process releases a very small amount of energy.

Stage 1: Glycolysis

• means "splitting sugars" ….6 carbon glucose is split into two 3 carbon molecules (pyruvate)

• Occurs in the cytoplasm of cells

• With or Without O2 not required (anaerobic)

• Some ATP produced• Net yield = 2 ATPs

The Krebs Cycle(a.k.a. citric acid cycle)

• Occurs in the mitochondria

• O2 required (aerobic)

• CO2 (waste)

• Some ATP produced• Net yield = 2 ATPs

Krebscycle

CoAacetyl coenzyme A

citric acid

CO2

NADHNAD+

oxaloacetic acid 1.

2.

3.

4.

5.

6.

-ketoglutaric acid

CO2

NAD+

NAD+

malic acid

NADH

NADHFADH2 FAD+

succinic acid

ATP

-ketoglutaric acidderivative

ADP

6 NADH

2 FADH2

electrontransport

chain

CO2

2 ATP

GLYCOLYSISSUMMARY OF THE KREBS CYCLE

Electron Transport Chain

• series of electron carriers in the membrane of the mitochondria

• Occurs in the inner membrane of mitochondria

• O2 required (aerobic)• A lot of ATP produced• Net yield = 32 ATPs

GLYCOLYSIS

ELECTRONTRANSPORTCHAIN

O2H2O

32ATP

KREBSCYCLE

ATP SYNTHESIS

mitochondrionmitochondrion

inner compartment

outer compartment

inner membrane

outer compartment

innermembrane

NADH

ELECTRON TRANSPORT CHAIN

ATP synthesis

ADP + P

ATP

NAD+

2 H+ + 1/2 O2

H2Oinner compartment

H+H+

H+H+

H+

H+

H+

H+ H+

H+

H+

H+

H+

H+ H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+H+ H+H+

H+

H+

H+

H+

Cellular RespirationReview…...

• 3 Stages: Stage 1: Glycolysis

• O2 not required (anaerobic)• Some ATP produced

Stage 2: Krebs Cycle• O2 required (aerobic)• Some ATP produced

Stage 3: Electron Transport System

• O2 required (aerobic)• Much ATP produced

Q. Where does each Stage occur?

A. Cytoplasm of the cell

A. Mitochondrion(matrix)

A. Mitochondrial innermembrane

TOTAL: 36ATP

2 ATPs

2 ATPs

32 ATPs

GLYCOLYSIS

KREBSCYCLE

Insert 1 Glucose 2 energytokens

(ATP)

2 energytokens

32 energytokens

ELECTRONTRANSPORT CHAIN

-

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-

reactants products

GLYCOLYSISglucose

Oxygen Water

2 ATP

2 NADH

2 NADH

6 NADH

2 FADH22 ATP

32 ATP

KREBSCYCLE

ELECTRONTRANSPORTCHAIN

glucose derivatives

carbon dioxide

carbon dioxide

cytosol

mitochondrion

Aerobic Respiration

• Oxygen combines with glucose to convert it into energy• Releasing carbon dioxide and water as waste products.

• glucose + oxygen carbon dioxide + water + lots of heat energy

Anaerobic Respiration

• Occurs if there is a lack of oxygen available for aerobic respiration

• Glucose is incompletely broken down • In this type of respiration a lot less energy is

produced and most of it is lost as heat.

Anaerobic Energy Production: Fermentation

• Lactic Acid Formed mainly by

animal muscle cells Occurs in some

unicellular organisms Glucose lactic acid +

a tiny amount of heat energy

• Alcoholic Fermentation Yeast cells, Bacteria Glucose alcohol +

carbon dioxide + a tiny amount of heat energy

Summary: Aerobic & Anaerobic

• Similarities: Glucose is broken down. Carbon dioxide is released. Energy is liberated.

• Differences:

Aerobic respiration Anaerobic respiration

Lots of energy released Little energy is released

Water is the end productLactic Acid or alcohol is the end product

Glucose is completely broken down

Glucose is partially broken down

Is dependent on oxygen Is not dependent on oxygen