Cellular Respiration Let’s Review Is a chemical process that uses

oxygen to convert chemical energy stored in organic molecules into another form of chemical energy – a molecule called ATP

Cells in plants and animals then use the ATP as their main energy supply.

Energy

The ability to perform work Ex: your heart muscle does work

every time it beats Two basic forms of energy

Potentialkinetic

Potential Energy

Is stored energy due to an object’s position or arrangement

Kinetic Energy

Energy of motion Anything that is moving Kinetic - “motion”

Thermal Energy

Energy that has been transferred

From areas that are warmer to cooler

Chemical Energy

Organic compounds store energy (potential) in the way their atoms are arranged.

This is called chemical energy

ATP - Nature's Energy Store

All living things, plants and animals, require a continual supply of energy in order to function.

The energy is used for all the processes which keep the organism alive.

Before the energy can be used, it is first transformed into a form which the organism can handle easily.

This special carrier of energy is the molecule adenosine triphosphate, or ATP.

Its Structure

The ATP molecule is composed of three components.

At the center is a sugar molecule, ribose (the same sugar that forms the

basis of RNA).

Attached to one side of this is a base (a group consisting of linked rings of carbon and nitrogen atoms); in this case the base is adenine.

The other side of the sugar is attached to a string of phosphate groups.

These phosphates are the key to the activity of ATP.

ATP consists of a base, in this case adenine (red), a ribose (magenta) and a phosphate chain (blue).

How it works

ATP works by losing the endmost phosphate group when instructed to do so by an enzyme.

This reaction releases a lot of energy, which the organism can then use to build proteins, contact muscles, etc

The reaction product is adenosine diphosphate (ADP),

ATP

ADP

Even more energy can be extracted by removing a second phosphate group to produce adenosine monophosphate (AMP).

AMP

When the organism is resting and

energy is not immediately needed, the reverse reaction takes place and the phosphate group is reattached to the molecule using energy obtained from food or sunlight.

he ATP molecule acts as a chemical 'battery', storing energy when it is not needed, but able to release it instantly when the organism requires it.

The Phosphorus Cycle The fact that ATP is Nature's

'universal energy store' explains why phosphates are a vital ingredient in the diets of all living things. Modern fertilizers often contain phosphorus compounds that have been extracted from animal bones.

These compounds are used by plants to make ATP. We then eat the plants, metabolise their phosphorus, and produce our own ATP. When we die, our phosphorus goes back into the ecosystem to begin the cycle again...

Cellular Respiration

Cellular Respiration A catabolic, exergonic, oxygen (O2)

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

C6H12O6 + 6O2 6CO2 + 6H2O + energy

glucose ATP

Question:

In what kinds organisms does cellular respiration take place?

Plants and AnimalsPlants - Autotrophs: self-

producers.Animals - Heterotrophs:

consumers.

Mitochondria Organelle where cellular respiration takes place.

Innermembrane

Outermembrane

Innermembrane space

Matrix Cristae

Breakdown of Cellular Respiration

Three main parts (reactions).

1. Glycolysis (splitting of sugar)a. cytosol, just outside of

mitochondria.

Breakdown of Cellular Respiration2. Krebs Cycle (Citric Acid Cycle)

a. mitochondrial matrix

3. Electron Transport Chain (ETC a.. inner mitochondrial membrane.

1. Glycolysis

Occurs in the cytosol just outside of mitochondria.

Two phases:A. Energy investment phase

a. Preparatory phase

B. Energy yielding phasea. Energy payoff phase

1. Glycolysis

A. Energy Investment Phase:

Glucose (6C)

Glyceraldehyde phosphate (2 - 3C) (G3P or GAP)

2 ATP - used0 ATP - produced0 NADH - produced

2ATP

2ADP + P

C-C-C-C-C-C

C-C-C C-C-C

1. Glycolysis

B. Energy Yielding Phase

Glyceraldehyde phosphate (2 - 3C) (G3P or GAP)

Pyruvate (2 - 3C) (PYR)

0 ATP - used4 ATP - produced2 NADH - produced

4ATP

4ADP + P

C-C-C C-C-C

C-C-C C-C-C

GAP GAP

(PYR) (PYR)

1. Glycolysis

Total Net Yield

2 - 3C-Pyruvate (PYR)2 - ATP 2 - NADH

2. 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.

MitochondrialMatrix

2. Krebs Cycle (Citric Acid Cycle)

KrebsCycle

1 Acetyl CoA (2C)

3 NAD+

3 NADHFAD

FADH2

ATP ADP + P

(one turn)

OAA (4C) Citrate (6C)

2 CO2

2. Krebs Cycle (Citric Acid Cycle)

KrebsCycle

2 Acetyl CoA (2C)

6 NAD+

6 NADH2 FAD

2 FADH2

2 ATP 2 ADP + P

(two turns)

OAA (4C)Citrate (6C)

4 CO2

2. Krebs Cycle (Citric Acid Cycle) Total net yield (2 turns of krebs cycle)

1. 2 - ATP (substrate-level phosphorylation)2. 6 - NADH3. 2 - FADH2

4. 4 - CO2

3. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis)

Location: inner mitochondrial membrane. Uses ETC and ATP Synthase (enzyme) to make

ATP.

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

InnerMitochondrialMembrane

3. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis) The H+ then moves via diffusion through ATP

Synthase to make ATP.

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).

TOTAL ATP YIELD

1. 04 ATP – glycolysis and krebs cycle2. 34 ATP - ETC 38 ATP - TOTAL YIELD

ATP

Maximum ATP Yield for Cellular Respiration (Eukaryotes)

36 ATP (maximum per glucose)

Glucose

Glycolysis

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

2 ATP(substrate-levelphosphorylation)

2NADH

2NADH6NADH

KrebsCycle

2FADH2

2 ATP(substrate-levelphosphorylation)

2 Pyruvate2 Acetyl CoA

ETC and Oxidative Phosphorylation

Cytosol

Mitochondria

Fermentation

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

Remember: glycolysis is part of fermentation. Two Types:

1. Alcohol Fermentation

2. Lactic Acid Fermentation

Alcohol Fermentation

Plants and Fungi beer and wine

glucose

Glycolysis

CCCCCC

CCC

2 Pyruvic acid

2ATP2ADP+ 2

2NADH

P

2 NAD+

CC

2 Ethanol2CO2

released

2NADH 2 NAD+

Lactic Acid Fermentation

Animals (pain in muscle after a workout).

2 Lactic acid

2NADH 2 NAD+

CCC

Glucose

GlycolysisCCC

2 Pyruvic acid

2ATP2ADP+ 2

2NADH

P

2 NAD+

CCCCCC

Lactic Acid Fermentation

End Products: Lactic acid fermentation

2 - ATP 2 - Lactic Acid molecules

Alcohol Fermentation

End Products: Alcohol fermentation

2 - ATP

2 - CO2

2 – molecules of ethanol

Question:

In addition to glucose, what other various food molecules are use in Cellular Respiration?

Catabolism of VariousFood Molecules Other organic molecules used for fuel.

1. Carbohydrates: polysaccharides

2. Fats: glycerol’s and fatty acids

3. Proteins: amino acids