Cellular Respiration

Chapter 9

Food = source of energy

A Calorie – is the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius.

Cells don’t “burn” glucose or other foods. Instead, they gradually release the energy.

The Calorie used on food labels is a kilocalorie, or 1000 calories

Feel the BurnDo 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.

1.How does your body feel at the start of exercise, such as a long, slow run? 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 changes in how you feel?3.Think about running as fast as you can for 100 meters. Could you keep up this pace for a much longer distance? Explain your answer.

Cellular Respiration

The process that releases energy by breaking down glucose & other food molecules in the presence of oxygen.

6O2 + C6H12O6 → 6CO2 + 6H2O + Energy

oxygen + glucose → carbon dioxide + water + energy

Aerobic Respiration

3 Stages make up Cellular Respiration

Glycolysis Kreb Cycle Electron Transport

Glucose

Glycolysis Krebs cycle

Electrontransport

Fermentation (without oxygen)

Alcohol or lactic acid

Chemical PathwaysSection 9-1

GlucoseGlycolysis

Cytoplasm

Pyruvic acid

Electrons carried in NADH

Krebs Cycle

Electrons carried in

NADH and FADH2 Electron

Transport Chain

Mitochondrion

Figure 9–2 Cellular Respiration: An Overview

Mitochondrion

Section 9-1

3 Stages make up Cellular Respiration

Glycolysis – process in which 1 molecule of glucose is broken in half, producing 2 molecules of pyruvic acid & gains 2 ATP molecules. O2 present - it is followed by the Kreb Cycle & the

electron transport chain. O2 not present (anaerobic) - it is followed by

fermentation.

Glucose

To the electron transport chain

Figure 9-3 GlycolysisSection 9-1

2 Pyruvic acid

Glycolysishttp://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html

Fermentation

Fermentation – releases energy in food & converts NADH back into NAD+ keeping the supply of ATP constant.

Alcoholic fermentation – yeasts & a few other microorganisms; causes bread dough to rise.

Lactic Acid fermentation – in muscles during rapid exercise when the body can’t supply enough O2 to the tissues; without oxygen, the body isn’t able to produce the ATP required. Buildup causes pain & soreness.

Glucose Pyruvic acidLactic acid

Figure 9–4 Lactic Acid Fermentation

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?

Section 9-2

FlowchartSection 9-2

Glucose(C6H1206)

+Oxygen

(02)

GlycolysisKrebsCycle

ElectronTransport

Chain

Carbon Dioxide

(CO2)+

Water(H2O)

Cellular Respiration

3 Stages make up Cellular Respiration

Kreb Cycle – requires O2 (aerobic) In eukaryotes. Takes place in the mitochondria. Aka. Citric acid cycle b/c it’s one of the first products. Pyruvic acid is broken down into CO2 which is

released into the air. NAD+ is changed to NADH & FAD is changed to

FADH2 which carry high-energy electrons to the electron transport chain.

The Krebs Cyclehttp://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_the_krebs_cycle_works__quiz_1_.html

The Krebs Cycle

Citric Acid Production

Figure 9–6 The Krebs Cycle

Mitochondrion

3 Stages make up Cellular Respiration

Electron Transport – uses high-energy electrons from the Krebs cycle to convert ADP into ATP. In eukaryotes it’s composed of carrier proteins located in the

mitochondria. In prokaryotes the same chain is in the cell membrane where

energy is used to move H+ ions through ATP synthase. ATP synthase – protein sphere that spins, adding a phosphate

to ADP creating ATP.

The Electron Transport Chain

The Electron Transport Chain

Figure 9–7 Electron Transport Chain

Electron TransportHydrogen Ion Movement

ATP Production

ATP synthase

Channel

Inner Membrane

Matrix

Intermembrane Space

Mitochondrion

Cellular Respiration

Glycolysis + Krebs + Electron Transport = 36 ATP / glucose molecules.

The Human Body

Contains small amounts of ATP. When the body needs energy fast, muscle

cells produce ATP by Lactic Acid Fermentation.

For long-term needs, the body must use cellular respiration.

Comparing Photosynthesis & Cellular Respiration Energy flows in Photosynthesis Cellular Respiration takes place in the

opposite direction.Photosynthesis – removes CO2 & puts O2

back into air.Cellular Respiration – removes O2 & puts CO2

back into air.

Comparing Photosynthesis & Cellular Respiration Cellular Respiration

6O2 + C6H12O6 → 6CO2 + 6H2O + Energy

Photosynthesis

6CO2 + 6H2O + light→C6H12O6 + 6O2