Cellular Respiration

Cellular Respiration

Photosynthesis CO2 + H2O + energy sugars + O2

Cell Respiration

Sugars + O2 CO2 + H2O + energy

Cellular Respiration

• You breathe air into your lungs. The oxygen in the air you breathe is absorbed into the blood in the capillaries that surround your lungs and then transported via the pulmonary vein into the left side of your heart.

• The oxygenated blood is pumped out of the left side of your heart and into the arteries that deliver it throughout your body to your muscles.

• When the oxygenated blood reaches your muscles the oxygen is absorbed into your muscle cells. . At the same time that your blood is providing oxygen to your muscles, it is also removing carbon dioxide

• The de-oxygenated and carbon dioxide rich blood is pumped out of the right side of your heart to your lungs via your pulmonary artery. Once in the lungs, your blood releases the carbon dioxide into the air that you breathe out and absorbs more oxygen from the air that you breathe in, and the entire process begins again.

Glucose + O2 → CO2 + H2O (l) + ATP

Cellular Respiration

Generate ATP

How Do cells make ATP

• Fermentation—NO oxygen• Anaerobic Respiration—no oxygen• Aerobic Respiration—OXYGEN– Reverse process of photosynthesis

– Takes place in mitochondria– Harvest potential energy in food, use it to make ATP

• ALL organisms do some sort of ATP generation

C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP

Aerobic Respiration

• Redox reaction– Oxidize glucose and reduce oxygen

• Carried out in 3 steps1. Glycolysis—breaking a 6-carbon glucose into 2 3-

carbon pyruvate molecules, use NADH to catch electrons

2. Krebs Cycle—oxidize pyruvate, release C02 ,and FADH2

3. Electron Transport Chain—transfers electrons from NADH and FADH2 down a gradient using ATP synthase to make ATP

Aerobic Respiration

Mitochondria

• Glycolysis takes place in cell’s cytoplasm• Rest of the reactions take place in mitochondria– Cristae—folds to increase surface area of inner

membrane– Intermembrane compartment—area between 2

membranes• Electron transport chains

– Matrix—space within the inner membrane• Krebs Cycle

Structure of Mitochondrion

Glycolysis

• Can be done with or without oxygen• Done in cell’s cytoplasm• 10 Steps– First 5 steps “prepare” glucose– Last 5 steps get the energy out

• Produces 2 molecules of ATP– Substrate level phosphorylation– Does NOT need proton gradient or ATP synthase

(like chemiosmotic phosphorylation)

First 5 Steps

Last 5 Steps

Stages of Cellular RespirationGlycoysis

Formation of Acetyl CoA

• Before we can start Krebs Cycle have to convert pyruvate

• In mitochondrial matrix• Pyruvate loses CO2 molecule• NADH reduced to NADH• Acetyl CoA = 2 Carbon molecule

Acetyl CoA

Krebs Cycle

• Occurs mitochondria matrix• Cycle turns 2 times for every glucose molecule1. Acetyl CoA loses coenzyme = 2 Carbon

molecule2. 2-Carbon + oxaloacetate = citrate3. CO2 released

4. Electrons transferred to NADH and FADH25. ATP made by substrate level phosphorylation

Outputs of Krebs Cycle

• 4 CO2

• 2 ATP• 6 NADH• 2 FADH2

• Heat• Intermediate molecules in cycle can be used

to make other organic molecules, amino acids, fats

Cellular Respiration: NADH

Cellular Respiration: NADH

Electron Transport Chainhttp://media.pearsoncmg.com/bc/bc_0media_bio/bioflix/bioflix.htm?cc7respirationJust first subsection: overview

(Krebs Cycle)

Electron Transport Chain

• Takes place across the inner mitochondrial membrane

• Uses /electrons from NADH and FADH2

• NADH and FADH2 donate electrons to enzymes in membrane to create H+ gradient

• In AEROBIC respiration final electron acceptor is O2

– O2 combines with H+ to make water• ATP finally made by chemiosmotic

phosphorylation – Protons through ATP synthase to turn ADP to ATP

Electron Transport Chain

Stages of Cellular Respiration: Chemiosmosis

http://www.youtube.com/watch?v=zfvVvC4-u_A&feature=related

Final Outputs of Respiration

Aerobic RespirationPer 1 Glucose Molecule• 10 NADH• 2 FADH2

• 36 ATP

Alternate Energy Pathways

Anaerobic Respiration• No oxygen• Different terminal

electron acceptor– NO3-, SO4-, CH4

• Amount of ATP produced depends on terminal electron acceptor

• Fermentation• No oxygen• Only uses glycolysis• Only generates 2 ATP• Can use sugar, alcoholic,

lactic acid

Different Types of Fermentation

Pyruvic acid CO2 + acetaldehyde + NADH ethanol + NAD+

Photosynthesis v. Cellular Respiration

Photosynthesis Cellular RespirationEnergy source Light Food

Energy released No, stored Yes

Reactants H2O, CO2Glucose, O2

Products Glucose, O2 CO2, H2O

22

O2

Glucose

2 Pyruvate

NADHNADHNADHFADH2

ATPATPATP34

H2O CO2

Glycolysis

Carbonreactions

Photosynthesis

ATP

NADPH

NADP+

ADP

Cellular respiration

Electrontransport

chain

Krebscycle

2AcetylCoA

Lightreactions

Connections Among Metabolic Pathways

Connections Among Metabolic Pathways