Cellular Respiration

• Do you like to run, bike, or swim? These all are good ways to exercise. When you exercise, your body uses oxygen to get energy from glucose,a six-carbon sugar.

Section 9-1

1. How does your body feel at the start of exercise, such as a long, How does your body feel at the start of exercise, such as a long, slowslowrun? How do you feel 1 minute into the run; 10 minutes into the run? How do you feel 1 minute into the run; 10 minutes into the run?run?

2. What do you think is happening in your cells to cause the changes2. What do you think is happening in your cells to cause the changesin how you feel?in how you feel?

3. Think about running as fast as you can for 100 meters. Could you3. Think about running as fast as you can for 100 meters. Could youkeep up this pace for a much longer distance? Explain your answer.keep up this pace for a much longer distance? Explain your answer.Go to

Section:

Feel the Burn

Energy in Food

• Energy is measured in calories (C) = the amount of energy needed to raise the temperature of 1 gram of water 1 Celsius degree.

• Cells release the energy from glucose and other food compounds through multiple steps

• The energy from food is used to make ATP (a form of energy your cells can use)

Mitochondria

• Breakdown process occurs in mitochondria.

• The mitochondria is known as the cell’s “Power-house!”

Output

CO2 H2O

Cellular Respiration• Cellular respiration is the

process of breaking down food (glucose) in cells in the presence of oxygen to release energy.

• In the presence of oxygen, food is broken down through the processes of glycolysis, the Krebs cycle and the electron transport chain = cellular respiration

• It uses oxygen taken in as you breath = aerobic

• Carbon dioxide, water, energy, and some heat are given off as waste products.

Glucose

Glycolysis Krebs cycle

Electrontransport

Fermentation (without oxygen)

Alcohol or lactic acid

Chemical PathwaysSection 9-1

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Cellular Respiration Equation

• Requirements:– C6H12O6 – organic sugar

comes from digested foods eaten

– 6O2 – oxygen comes from air you breathe

• Products:– 6CO2 – carbon dioxide is

released by breathing out

– 6H2O – water is released as a waste in your urine, sweat or breath

– Energy – chemical ATP energy is released

CC66HH1212OO66 + 6O + 6O22 6CO 6CO22 + 6H + 6H22O + energyO + energy sugarsugar oxygenoxygen carbon carbon waterwater

(glucose)(glucose) dioxide dioxide

Cellular Respiration Equation

• Does this look similar to photosynthesis?– Are these products seen in photosynthesis?– Are these requirements seen in photosynthesis?

CC66HH1212OO66 + 6O + 6O22 6CO 6CO22 + 6H + 6H22O + energyO + energy sugarsugar oxygenoxygen carbon carbon waterwater

(glucose)(glucose) dioxide dioxide

Compare Photosynthesis and Cellular Respiration

PhotosynthesisPhotosynthesis Cellular Cellular RespirationRespiration

FunctionFunction Store energyStore energy Release energyRelease energy

LocationLocation Chloroplasts – in Chloroplasts – in plants, algae and plants, algae and some bacteriasome bacteria

Mitochondria – in Mitochondria – in all eukaryotes and all eukaryotes and some prokaryotessome prokaryotes

ReactantsReactants Carbon dioxide & Carbon dioxide & waterwater

Glucose & oxygenGlucose & oxygen

ProductsProducts Glucose & oxygenGlucose & oxygen Carbon dioxide & Carbon dioxide & waterwater

EquationEquation 6CO6CO22 + 6H + 6H22O O

CC66HH1212OO66 + 6O + 6O22

CC66HH1212OO66 + 6O + 6O2 2

6CO6CO22 + 6H + 6H22O O

It is a CYCLE!• The chloroplasts and mitochondria transform

energy in the cell and feed off each others’ waste products. – Chloroplasts use the CO2 given off by mitochondria.

– Mitochondria use O2 given off by chloroplasts

Why do plants have both chloroplasts and mitochondria?

• 1. Summer – chlorophyll captures sunlight and performs photosynthesis

• 3. Winter – The stored energy keeps the plant alive without leaves

• 2. Fall – The chemical energy (glucose) is stored

• 4. Spring – The mitochondria break down glucose to release energy through cellular respiration to produce new buds to make leaves

GlucoseGlycolysis

Cytoplasm

Pyruvic acid

Electrons carried in NADH

Krebs Cycle

Electrons carried in NADH

and FADH2

Electron Transport Chain

Mitochondrion

Figure 9–2 Respiration: An Overview

Mitochondrion

Section 9-1

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Interest Grabber• Rolling and Folding• Some of the steps in cellular respiration take place in the

membrane inside the cell structure called the mitochondrion, which has a folded inner membrane. – What purpose do these folds serve? – What has happened to the surface area of the inside of the rolled paper?– What would be the value of increasing the surface area of the membrane

inside a mitochondrion?

Section 9-2

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FlowchartSection 9-2

Glucose(C6H1206)

+Oxygen

(02)

Glycolysis KrebsCycle

ElectronTransport

Chain

Carbon Dioxide

(CO2)+

Water(H2O)

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Cellular Respiration

Glycolysis

• One molecule of glucose is broken in half producing two molecules of pyruvic acid, a 3-carbon compound

• ATP Production: 2 ATP molecules are put into glycolysis to start the process and 4 ATP are made, so the net gain = 2 ATP

• NADH Production: NAD+ accepts electrons making NADH to help pass energy from glucose to other pathways in the cell

Krebs Cycle• Pyruvic acid is broken

down into carbon dioxide and released in a series of energy-extracting reactions

• Electrons are transferred to energy carriers (4 NADH & 1 FADH2)

• 1 ATP is produced.

Electron Transport

• The high-energy electrons from the Krebs cycle are passed to the electron transport chain to convert ADP into ATP– Every pair of electrons

transported makes 3 ATP– Oxygen accepts the

electrons and releases them as water

http://www.qcc.cuny.edu/biologicalsciences/Faculty/DMeyer/respiration.html

Cellular Respiration Totals

• Glycolysis produces just 2 ATP from one glucose

• In the absence of oxygen, only 2 ATP produced

• In the presence of oxygen, the Krebs cycle and electron transport chain produce 34 more ATP, totaling in 36 ATP = a lot of energy!