Cellular RespirationCellular Respiration

1. Harvesting Chemical Energya. Plants and animals both use products of

photosynthesis (glucose) for metabolic fuelb. Heterotrophs: must take in energy from

outside sources, cannot make their own e.g. animals

c. When we take in glucose (or other carbs), proteins, and fats-these foods don’t come to us the way our cells can use them

2. Cellular Respirationa. Cellular Respiration is the process

that releases energy by breaking down food molecules in the presence of oxygen.

b. These reactions proceed the same way in plants and animals.

c. 6O2 + C6H12O6 6CO2 + 6H2O + ATP Energy

d. Oxygen + Glucose Carbon Dioxide + Water + Energy

3. Cellular Respiration Overview

a. Breakdown of glucose begins in the cytoplasm: the liquid matrix inside the cell

b. At this point life diverges into two forms and two pathwaysi. Anaerobic cellular respiration (aka

fermentation)ii. Aerobic cellular respiration

GlucoseGlucose

Glycolysis Glycolysis Krebs Krebs cycle cycle

ElectronElectrontransporttransport

Fermentation Fermentation (without (without oxygen)oxygen)

Alcohol or Alcohol or lactic acidlactic acid

Chemical PathwaysSection 9-1Section 9-1

a. Series of reactions which break the 6-carbon glucose molecule down into two 3-carbon molecules called pyruvate

b. Process is an ancient one-all organisms from simple bacteria to humans perform it the same way

c. Yields 2 ATP molecules for every one glucose molecule broken down

d. Yields 2 NADH per glucose molecule

4. Glycolysis4. Glycolysis

GlucoseGlucose

To the To the electron electron transport transport

chainchain

GlycolysisSection 9-1Section 9-1

2 Pyruvic acid2 Pyruvic acid

5. Fermentationa. Releases energy from glucose without the

presence of oxygen.b. There are two types of fermentation:

alcoholic and lactic acid.i. Alcoholic fermentation is done by yeasts and

some microorganisms. It produces alcohol & Carbon Dioxide

ii. Lactic Acid is produced by muscles during rapid exercise when the body cannot supply enough oxygen.

6. Anaerobic Cellular Respirationa. Some organisms thrive in environments with

little or no oxygeni. Marshes, bogs, gut of animals, sewage treatment

ponds

b. No oxygen used= ‘an’aerobicc. Results in no more ATP, final steps in these

pathways serve ONLY to regenerate NAD+ so it can return to pick up more electrons and hydrogen in glycolysis.i. End products such as ethanol and CO2 (single cell fungi

(yeast) in beer/bread) or lactic acid (muscle cells)

Glucose Pyruvic acid Lactic acid

Lactic Acid FermentationLactic Acid FermentationSection 9-1

7. Aerobic Cellular Respiration

a. Oxygen required=aerobicb. 2 more sets of reactions which occur

in a specialized structure within the cell called the mitochondriai. Kreb’s Cycleii. Electron Transport Chain

GlucoseGlucoseGlycolysisGlycolysis

CytoplasmCytoplasm

Pyruvic Pyruvic acidacid

Electrons carried in NADHElectrons carried in NADH

Krebs Krebs CycleCycle

Electrons Electrons carried in carried in NADH and NADH and

FADHFADH22 Electron Electron Transport Transport

ChainChain

MitochondrionMitochondrion

  Cellular Respiration: An Cellular Respiration: An OverviewOverview

MitochondrionMitochondrion

Section 9-1Section 9-1

8. The Krebs Cycle

a. During the Krebs Cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

b. Citric Acid is created in this cycle thus giving it the nickname Citric Acid cycle.

c. Net ATP Production is 2 ATP.

8. Kreb’s Cycle

c. Completes the breakdown of glucosei. Takes the pyruvate (3-carbons) and breaks it

down, the carbon and oxygen atoms end up in CO2 and H2O

ii. Hydrogen and electrons are stripped and loaded onto NAD+ and FAD to produce NADH and FADH2

d. Production of only 2 more ATP but loads up the coenzymes with H+ and electrons which move to the 3rd stage

9. Electron Transport Chain

a. The electron transport chain uses the high-energy electrons from the Krebs Cycle to convert ADP to ATP.

b. Total ATP 32.

9. Electron Transport Chainc. Electron carriers loaded with electrons

and protons from the Kreb’s cycle move to this chain-like a series of steps (staircase).

d. As electrons drop down stairs, energy released to form a total of 32 ATP

e. Oxygen waits at bottom of staircase, picks up electrons and protons and in doing so becomes water

 Electron Transport ChainSection 9-2

Electron TransportHydrogen Ion Movement

ATP Production

ATP synthase

Channel

Inner Membrane

Matrix

Intermembrane Space

Mitochondrion

10. Energy Tallya. 36 ATP for aerobic vs. 2 ATP for

anaerobic

i. Glycolysis 2 ATP

ii. Kreb’s 2 ATP

iii. Electron Transport 32 ATPi. 36 ATP

b. Anaerobic organisms can’t be too energetic but are important for global recycling of carbon

Section 9-2

Glucose(C6H1206)

+Oxygen

(02)

Glycolysis

KrebsCycle or

Citric AcidCycle

ElectronTransport

Chain

Carbon Dioxide(CO2)

+Water(H2O)

Aerobic Cellular Respiration

11. Energy & Exercise

a. Quick energy – Lactic Acid fermentation is used to get quick energy and gives off lactic acid as a by product, thus the muscle pain.

b. Long-Term Energy – Use cellular respiration to produce energy. Exercising or activities that last for at least 15 to 20 minutes. Best form for weight control.

12. Comparing Photosynthesis & Respiration

Photosynthesis Cellular Respiration

Function Energy Storage Energy Release

Location Chloroplasts Mitochondria

Reactants CO2 and H2O C6H12O6 and O2

Products C6H12O6 and O2 CO2 and H2O

Equation 6CO2 + 6H2O C6H12O6 + 6O2

C6H12O6 + 6O2

6CO2 + 6H2O