5.2: Cellular Respiration

(Aerobic Respiration)

Plants—make food (sugar) through photosynthesis

Animals and other organisms—get food by eating plants and animals

Energy Review

Why do we need food?

Cellular respiration— glucose and food are broken down to make energy (ATP) in ALL organisms Occurs in the mitochondria of eukaryotes Occurs in the cytoplasm of prokaryotes

Cellular Respiration

C6H12O6 + O2 CO2 + H2O + energy

Cellular Respiration Equation

Aerobic Respiration: breaking down of glucose molecules into smaller pieces in the presence of oxygen to produce ATP

Cellular Respiration

THREE STEPS OF AEROBIC RESPIRATION1. Glycolysis2. Kreb’s/Citric Acid Cycle3. Electron Transport Chain (ETC)

Cellular Respiration

1. Glycolysis: occurs in cytoplasm; glucose is split in half, forming a pyruvate molecule

2 ATP released Electrons released and carried to

mitochondria by NADH

Cellular Respiration

Cellular Respiration

Glycolysis quiz Where does glycolysis take place?

What molecule is used in glycolysis?

What are the products of glycolysis?

What ultimately happens to each of these products?

Write an equation that represents glycolysis

2. Kreb’s/Citric Acid Cycle: occurs in the mitochondria matrix; pyruvate is split into smaller pieces

CO2 gas released (we breathe it out) 2 ATP released Electrons released and move to

mitochondrial membrane by NADH and FADH2

Cellular Respiration

Cellular Respiration

FAD+ FADH FAD+

NAD+ NADH NAD+

Krebs/Citric Acid Cycle Quiz

Where does the CAC occur?

What molecule is used in the CAC?

What are the products of the CAC? What happens to each of these

products?

Write an equation that represents the CAC

3. Electron Transport Chain (ETC): made of proteins; occurs in the mitochondria

NADH & FADH2 drop off electrons at proteins Electrons lose energy as get passed from

protein to protein Energy used to make ATP (ATP Synthase)

32 ATP made Electrons finally passed to OXYGEN to make

WATER

Cellular Respiration

TOTAL ENERGY: 36 ATP from 1 glucose

Cellular Respiration

ETC quiz What is the ETC?

What molecules bring the electrons to the ETC?

What happens as the electrons get passed from protein to protein down the ETC?

What happens to the extra energy?

What happens to the electrons at the end of the ETC?

CR Animation

Glycolysis

Krebs Cycle (CAC)

ETC

Glucose

Pyruvate

NA

DH

CO2

ATP

ATP

O2

NA

DH

FA

DH

2

ATP

H2O

Cellular Respiration(Anaerobic

Respiration)

Anaerobic Respiration: breaking down glucose molecules into smaller pieces the ABSENCE of oxygen to produce ATP

Cellular Respiration

TWO STEPS OF ANAEROBIC RESPIRATION1. Glycolysis: occurs in cytoplasm; glucose is split in half, forming a pyruvate molecule

2 ATP released Electrons released and carried to

mitochondria

Cellular Respiration

TWO STEPS OF ANAEROBIC RESPIRATION 2. Fermentation: breaking down pyruvate

without oxygen

Cellular Respiration

Lactic acid fermentation: pyruvate is broken down into lactic acid + ATP 2 ATP released Lactic acid builds up as in muscle cells & causes

burning sensation (muscle cramping) during strenuous exercises

C-C-C + NADH H-C-C-C + ATP + NAD+

pyruvate e’ carrier lactic acid energy carrier

Cellular Respiration

Alcoholic fermentation: pyruvate is broken down into alcohol, carbon dioxide, and ATP in yeast and bacterial cells 2 ATP released

Used in making bread and alcohol beer

C-C-C + NADH C-C-OH + CO2 + ATPPyruvate + e’ carrier alcohol + carbon +

energy dioxide

Cellular Respiration

Eat Digestion Glycolysis

Citric acid cycle

Electron transport chain

Oxygen is present

No oxygen is present

Fermentation

(anaerobic respiration)

Lactic acid fermentation

Alcoholic fermentation

In animals

In yeast

Aerobic respiration

Cellular Respiration

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Cellular Respiration

Photosynthesis vs. Respirationfood synthesized food broken downrequires energy produces energyChloroplast mitochondria/cytoplasmOnly autotrophs Autotrophs and heterotrophs

(all living cells)