Chapter 9: Overview of Energy

Chapter 9: Overview of Energy

Respiration vs Breathing

Photosynthesis: (Net Reaction)

Respiration:

(Net Reaction) AEROBIC CONDITIONS (O2 needed)

• In both reactions, there is a HYDROGEN and CARBON pathwaya. Photosynthesis-- Joins the hydrogen and oxygen pathway to

form glucoseb. Respiration-- Separates these 2 pathways forming H2O and CO2

Chapter 9: Cell Respiration Notes

Aerobic Cell Respiration• Complete oxidation of 1 glucose molecule• Includes 4 major sets of reactions

NOTE: Parts 2, 3, 4 occur in mitochondria of aerobic cells only Part 4 occurs simultaneously with Parts

1, 2, 3 in aerobic cells

Aerobic Cell Respiration

• Review of Electron Carriers

a. NAD + 2H + 2e- NADH + H+

b. FAD + 2H + 2e- FADH2

Bring e- to ETC of inner mitochodrial membrane

Fermentation

• Aka Anaerobic Respiration

• Catabolic process that partially breaks down sugars without the use of oxygen

• Function of fermentation is to make ATP

Alcoholic Fermentation

PGAL

PGAL

Pyruvicacid

Pyruvic acid

Fermentation cont.

Fermentation Via:

Alcoholic FermentationGlycolysis followed by: pyruvic acid + NADH 2 alcohol + 2 CO2 + NAD+

Pyruvic Acids

(Alcohol)

Lactic Acid FermentationGlycolysis followed by: pyruvic acid + NADH 2 lactic acid + NAD+

(Lactic Acid)

Pyruvic Acids

Glycolysis

• Splitting of 1 glucose molecule into 2 molecules of pyruvic acid

• Can occur aerobically or anaerobically

Glucose

PGAL

Pyruvic Acid

ATP made by process called SUBSTRATE- LEVEL PHOSPHORYLATION: transfer of phosphate group from a substrate (reactant) molecule to ADP ATP

Glycolysis

After Glycolysis

Respiration (4 Major Reactions)

1) Glycolysis (in cytoplasm)• Splitting of 1 molecule of glucose into 2 molecules

of pyruvic acid• Can occur in aerobic or anaerobic conditions

Glucose

PGAL

Pyruvic Acid

Respiration (4 Major Reactions) cont.

2) Pyruvic Acid Oxidation: Aerobic (in matrix)

The Oxidation of Pyruvate to form Acetyl CoA for Entry Into the Krebs Cycle

Kreb’s Cycle Pyruvic Acid

Oxidation

Respiration (4 Major Reactions) cont.

3) Kreb’s Cycle/ Citric Aid Cycle (in matrix)

Kreb’s Cycle Pyruvic Acid

Oxidation

Citric AcidOxaloacetic Acid

Citric Acid Cycle (x2)

ETC

Respiration (4 Major Reactions) cont.

Oxidative Phosphorylation

High [H+]Low pH

Low [H+]High pH

Chapter 9: Methods of ATP Synthesis Notes

3 Methods of ATP Synthesis

1) Photosynthetic Phosphorylation• Process of making ATP (~P) with light energy

using electrons from hydrogen and chlorophyll• Occurs during PSII• On thylakoid membranes- in grana within

chloroplast• Need enzyme (ATP synthetase & proton

pumps)- chemiosmosis• Has ETC-- Electron Transport Chain-- PSII and

PSI

Photosynthetic Phosphorylation

4e- 4e- 4e-

4H+

Photosynthetic Phosphorylation

3 Methods of ATP Synthesis cont.

2) Substrate Phosphorylation• Process of making ATP by rearrangement of

bonds of substrates during glycolysis or Krebs Cycle (No energy added!)a. Glycolysis (in cytoplasm)o Occurs in aerobic and anaerobic

conditionso No enzyme (ATP synthetase & proton

pump)o No ETC-- no H2O made

a. Glycolysis (in cytoplasm) cont.

3 Methods of ATP Synthesis cont.

b. Krebs Cycle (in mitochondrion)o Occurs only under aerobic conditionso No enzyme (ATP synthetase & proton pump)o No ETC-- no H2O made

3 Methods of ATP Synthesis cont.

3) Oxidative Phosphorylation• Process of making ATP (~) from energy

released from hydrogen electrons (e-) as they are carried to O2 by coenzymes via the ETC or respiratory chain

• Occurs only under aerobic conditions• Occurs only inside mitochondria (on

cristae membranes)

Oxidative Phosphorylation cont.

• Needs enzyme (ATP synthetase + proton pump + ATP transport protein)

• Needs ETC or respiratory chain• Final electron/ hydrogen acceptor is oxygen• H2O is made

Oxidative Phosphorylation

Oxidative Phosphorylation

Conversions:

a. NADH (produced in the cytoplasm) produces 2 ATP by the ETC

b. NADH (produced in the mitochondria) produces 3 ATP by the ETC

c. FADH2 (adds its electrons to the ETC at a lower level than NADH) so it produces 2 ATP

Net Energy Production from Aerobic Respiration

1. Glycolysis: 2 ATP 2. Krebs Cycle: 2 ATP 3. Electron Transport Phosphorylation: 32 ATP

a. Glycolysis: net gain/ 2 NADH (x 2) = 4 ATPb. Pyruvate Acetyl CoA: 2 NADH (x 3) = 6 ATPc. Krebs Cycle: 6 NADH (x 3) = 18 ATP

2 FADH2 (x 2) = 4 ATP

GRAND TOTAL: 36 ATP!!!