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Cellular Respiration

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Cellular Respiration

An oxygen (O2) requiring process that uses energy extracted from macromolecules (glucose) to produce energy (ATP) and water (H2O).

C6H12O6 + 6O2 6CO2 + 6H2O + glucose ATP

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Plants and Animals

Both Plants and Animals will use cellular respiration for energy.

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Mitochondria

Organelle where cellular respiration takes place.

Inner

membrane

Outer

membrane

Inner

membrane spaceMatrix

Cristae

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Redox Reaction

Transfer of one or more electrons from one reactant to another.

Two types:

1. Oxidation

2. Reduction

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Oxidation Reaction

The loss of electrons from a substance.

Or the gain of oxygen.

C6H12O6 + 6O2 6CO2 + 6H2O + energy

glucose ATP

Oxidation

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Reduction Reaction

The gain of electrons to a substance.

Or the loss of oxygen.

glucose ATP

C6H12O6 + 6O2 6CO2 + 6H2O + energy

Reduction

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Breakdown of Cellular Respiration

Four main parts (reactions).

1. Glycolysis (splitting of glucose)

a. This occurs in the cytoplasm just outside of mitochondria.

2. Grooming Phase

a. The two ½ glucose molecules

migration from cytoplasm to the matrix.

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Breakdown of Cellular Respiration

3. Krebs Cycle (Citric Acid Cycle)

a. This occurs in the mitochondrial matrix

4. Electron Transport Chain (ETC) and

Oxidative Phosphorylation

a. This occurs in the inner mitochondrial membrane.

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1. Glycolysis

A. Energy Investment Phase:

Glucose (6C)

Glyceraldehyde phosphate (2 - 3C)

(G3P or GAP)

2 ATP - used

0 ATP - produced

0 NADH - produced

2ATP

2ADP + P

C-C-C-C-C-C

C-C-C C-C-C

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1. Glycolysis

Glyceraldehyde phosphate (2 - 3C)

(G3P or GAP)

The 2 products produced…

2 Pyruvates (2 3C molecules)

0 ATP - used

4 ATP - produced

2 NADH - produced4ATP

4ADP + P

C-C-C C-C-C

C-C-C C-C-C

GAP GAP

(PYR) (PYR)

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Fermentation

Occurs in cytoplasm when “NO Oxygen”is present (called anaerobic).

Glycolysis is part of fermentation.

Two Types:

1. Alcohol Fermentation

2. Lactic Acid Fermentation

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Alcohol Fermentation

Plants and Fungi beer and wine

glucose

Glycolysis

C

C

C

C

C

C

C

C

C2 Pyruvic

acid

2ATP2ADP

+ 2

2NADH

P

2 NAD+

C

C

2 Ethanol2CO2

released

2NADH 2 NAD+

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Lactic Acid Fermentation

Animals (pain in muscle after a workout).

2 Lactic

acid

2NADH 2 NAD+

C

C

C

Glucose

GlycolysisC

C

C

2 Pyruvic

acid

2ATP2ADP

+ 2

2NADH

P

2 NAD+

C

C

C

C

C

C

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2. Grooming Phase

Occurs when Oxygen is present (aerobic).

2 Pyruvate (3C) molecules are transported through the mitochondria membrane to the matrix and is converted to 2 Acetyl CoA (2C)molecules.

CytoplasmC

C

C2 Pyruvate

2 CO2

2 Acetyl CoA

C-C

2NADH2 NAD+

Matrix

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2. Grooming Phase

End Products: grooming phase

2 - NADH

2 - CO2

2- Acetyl CoA (2C)

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3. Krebs Cycle (Citric Acid Cycle)

Location: mitochondrial matrix.

Acetyl CoA (2C) bonds to Oxalacetic acid (4C - OAA) to make Citrate (6C).

It takes 2 turns of the krebs cycle to oxidize 1 glucose molecule.

Mitochondrial

Matrix

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3. Krebs Cycle (Citric Acid Cycle)

Krebs

Cycle

1 Acetyl CoA (2C)

3 NAD+

3 NADH

FAD

FADH2

ATP ADP + P

(one turn)

OAA (4C) Citrate (6C)

2 CO2

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3. Krebs Cycle (Citric Acid Cycle)

Krebs

Cycle

2 Acetyl CoA (2C)

6 NAD+

6 NADH

2 FAD

2 FADH2

2 ATP 2 ADP + P

(two turns)

OAA (4C)Citrate (6C)

4 CO2

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3. Krebs Cycle (Citric Acid Cycle)

Total net yield (2 turns of krebs cycle)

1. 2 - ATP

2. 6 - NADH

3. 2 - FADH2

4. 4 - CO2

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4. Electron Transport Chain (ETC) (Chemiosmosis)

Location: inner mitochondrial membrane.

Uses ETC and ATP Synthase (enzyme) to make ATP.

ETC pumps H+ (protons) across inner membrane (lowers pH in inner membrane space).

Inner

Mitochondrial

Membrane

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4. Electron Transport Chain (ETC) (Chemiosmosis)

The H+ then move via diffusion (Proton Motive Force) through ATP Synthase to makeATP.

All NADH and FADH2 converted to ATP during this stage of cellular respiration.

Each NADH converts to 3 ATP.

Each FADH2 converts to 2 ATP (enters the ETC at a lower level than NADH).

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Maximum ATP Yield for Cellular Respiration (Eukaryotes)

36 ATP (maximum per glucose)

Glucose

Glycolysis

2ATP 4ATP 6ATP 18ATP 4ATP 2ATP

2 ATP(substrate-level

phosphorylation)

2NADH

2NADH

6NADH

Krebs

Cycle

2FADH2

2 ATP(substrate-level

phosphorylation)

2 Pyruvate

2 Acetyl CoA

ETC and Oxidative

Phosphorylation

Cytoplasm

Mitochondria

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Catabolism of VariousFood Molecules

Other organic molecules used for fuel.

1. Carbohydrates: polysaccharides

2. Fats: glycerol’s and fatty acids

3. Proteins: amino acids