Cellular Respiration

Chapter 9

Interest Grabber

• Feel the Burn

• 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, slowrun? How do you feel 1 minute into the run; 10 minutes into the run?

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

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

Sunlight powers life• Autotrophs

– Photosynthesis– Producers

• Heterotrophs– Consumers

• Cellular respiration- converts energy into cell fuel (ATP

Why do living things need food?

• provides living things with the chemical building blocks they need to grow and reproduce.

• Source of raw materials for making new molecules

• source of energy

What do cells do with food?

• Cells gradually release energy from glucose and other food compounds in the form of ATP.

ATP

• Most of the energy from cell respiration is converted into ATP

• ATP is a substance that powers most cell activities.

• Energy in phosphate bonds

Cellular Respiration

• Process that releases energy by breaking down glucose to make ATP at each stage

• 3 Steps– Glycolysis– Kreb’s cycle– Electron Transport

Chain

Formula

Cellular Respiration3 stages:

1. Glycolysis –the breaking of glucose into pyruvate

2. Kreb’s Cycle–pathway which converts pyruvate

3. Electron Transport Chain- coverts NADH into ATP

The 3 steps of cellular respiration

1. Glycolysis2. Kreb’s cycle3. Electron Transport

Chain

• Each stage captures some of the chemical energy available in food molecules and uses it to produce ATP.

Glucose

Glycolysis Krebs cycle

Electrontransport

Fermentation (without oxygen)

Alcohol or lactic acid

Chemical Pathways

Section 9-1

Glycolysis

• Occurs in cytoplasm

• Does not require oxygen

• Net gain of ATP = 2• Molecule of

glucose is broken in half to two pyruvate molecules

(then goes into mitochondria)

Cellular Respiration

End of Glycolysis

• 90% of the energy of glucose still has not been used

• The energy is stored in the electrons of pyruvic acid

Cellular RespirationStage Two(Aerobic): Production of ATP

•Krebs Cycle • reactions that produce

energy-storing molecules (NADH and ATP)

• Pyruvate citric acid• In mitochondria• Carbon dioxide given

off

Citric Acid Production

Figure 9–6 The Krebs Cycle

Section 9-2

Mitochondrion

Mitochondria• The matrix where 3-

carbon pieces that came from carbohydrates are broken down to (CO2 and water)

• The cristae is where ATP is made

Stage 3- ETC- Electron transport chain

• Hot potato-electrons• Uses high energy electron to convert

NADH in to ATP• Oxygen gets the “hot potato” to

make water

Figure 9–7 Electron Transport Chain

Section 9-2

Electron TransportHydrogen Ion Movement

ATP Production

ATP synthase

Channel

Inner Membrane

Matrix

Intermembrane Space

Mitochondrion

Fermentation(anaerobic)

• When oxygen is not present, gylcolysis follows this pathway (anaerobic)

• Two types– Alcoholic

fermentation– Lactic Acid

Fermentation

Alcoholic Fermentation

• Yeasts and other microorganisms

• Causes bread to rise• Formula

Lactic Acid Fermentation

• Pyruvic acid can turn to lactic acid so gylcolysis can continue

• Produced in muscles during exercise when oxygen is used up

• Muscles continue to make ATP

Alcohol Fermentation

• Unicellular organisms also go through this process

• Used in the productions of foods and beverages-cheese, yogurt, sour cream, pickles, alcoholic beverages

Summary

Molecule Role in respiration

C6 H12O6 Broken down in glycolysis = 2 ATP made, pyruvate

O2 Accepts H+ in ETC, aids in making ATP * Aerobic respiration only

H2O Made in ETC, waste product

CO2 Made in Krebs cycle, waste product

Flowchart

Section 9-2

Glucose(C6H1206)

+Oxygen

(02)

Glycolysis KrebsCycle

ElectronTransport

Chain

Carbon Dioxide

(CO2)+

Water(H2O)

Cellular Respiration

Review