Photosynthesis, Cellular Respiration & Mitochondria Processes

Photosynthesis

CO2 + H2O -> C6H12O6 + O2

Respiration

C6H12O6 + O2 -> CO2 + H2O

Glycolysis Location

in cytoplasm

Krebs Cycle Location

Matrix of Mitochondria

ETC & ATPase Location

Cristae of Mitochondria

Aerobic Respiration

Requires O2

Anaerobic Respiration

No O2 required

Stages of Aerobic Respiration

Glycolysis, Import into the Mitochondria (Transition Step), Krebs Cycle (Citric Acid Cycle), Electron Transport Chain and ATP Synthesis

Glycolysis Parts

Part 1: Energy Investment, Part 2: Energy Payoff

Energy Investment Phase

Glucose(C6) + 2ATP -> Fructose-1-6bisphosphate(C6) + 2ADP

Cleavage & Rearrangement

Fructose 1-6 bisphosphate (C6) -> 2 G3P (C3)

G3P

Glyceraldehyde-3-phosphate

Glycolysis Part 2 Output

(G3P C3 -> -> -> Pyruvate C3) X2, Part 2 Energy Output: 4 ATP + 2 NADH

Glycolysis Summary Part 1

Substrate: Glucose (C6 sugar), Product (end of step 4): 2 C3 sugars, 1 Dihydroxyacetone phosphate (C3) + 1 Glyceraldehyde -3-phosphate (C3)

Glycolysis Summary Part 2

Dihydroxyacetone phosphate (C3) -> Glyceraldehyde -3-phosphate (C3), Substrate: 2 Glyceraldehyde -3-phosphate (C3), Product (end of step 4): 2 pyruvate (C3 sugars)

Glycolysis Energy Yield

Part 1 Energy Input: 2 ATP, Part 2 Energy Output: 2 NADH + 4 ATP, Net Energy Yield: 2 ATP + 2 NADH

Glycolysis Net Energy Yield

Part 1 Energy In: 2 ATP, Part 2 Energy Out: 4 ATP + 2 NADH, Net Energy Yield: 2 ATP + 2 NADH

Review of Respiration

4 Parts of Respiration, Location in Cell, Glycolysis Part 1, Energy Input, Cleavage & Rearrangement, Glycolysis Part 2, Glycolysis: Net Energy Yield

Import Into the Mitochondria

Pyruvate C3 + NAD+ + CoA -> acetyl CoA C2 + CO2 + NADH

Net Energy Yield/Glucose

2 NADH

Coenzyme A

Acetyl CoA = acetyl (from Pyruvate) attached to Coenzyme A

Glycolysis

2 Pyruvate C3

Import into Mito.

2 AcetylCoA C2 + 2 CO2

Krebs Cycle

2 AcetylCoA C2 + 2 Oxaloacetate C4 -> 2 Citric Acid C6 + 2CoA

1st Reaction of Krebs Cycle

AcetylCoA C2 + Oxaloacetate C4 -> Citric Acid C6 + CoA

Sugars are Rearranged

Decarboxylated -> CO2 released

Oxidized

Reduced, High energy compounds made NADH, FADH2

Substrate-level Phosphorylation

Method of making ATP in an Enzyme Reaction

Citric Acid Cycle

Also known as Krebs Cycle

Krebs Cycle Energy Yield per Cycle

1 ATP, 1 FADH2, 3 NADH

Krebs Cycle Energy Yield per Glucose

2 ATP, 2 FADH2, 6 NADH

Transition Step

Import into the Mitochondria

Aerobic Respiration: Net Energy Yield per Glucose

Total=4 ATP +10 NADH +2 FADH2

Electron Transport Chain & Oxidative Phosphorylation

Purpose: uses the energy in NADH and FADH2 to make ATP by Oxidative Phosphorylation = Chemiosmosis

Electron Transport

Makes a H+ gradient

Oxidative Phosphorylation

Uses the H+ gradient to make ATP

Redox Reactions

Reduced cmpd loses e-s and becomes oxidized; Oxidized cmpd gains e-s and becomes reduced

Types of Electron Carriers in the Electron Transport Chain

Protein Complexes in Cristae membrane: Complex I, Complex II, Complex III, Complex IV: Cytochrome c oxidase

Mobile Electron Carriers

Coenzyme Q/ Ubiquinone, Cytochrome c

Electron Transport Generates a Proton Gradient

As e-s are transported down the ETC, H+s are transported across the cristae membrane into the intermembrane space at 3 places: Complex I, Complex III, Complex IV

ATP Synthase

Uses H+ gradient as a source of energy to make ATP

Lack of O2

Poison: Cyanide

Poisons Stop Aerobic Respiration

Many Poisons stop e- transport -> no ATP synthesis

Arsenic

Stops Krebs Cycle, inhibits part of Glycolysis

What Happens if Electron Transport Stops?

No H+ gradient is made -> no energy to make ATP! ATP synthesis will stop. Electron carriers can't pass on their electrons, will all be stuck in reduced form.

Glycolysis: Part 2

If no O2 all NAD+ will be in NADH form. Any reaction that uses NAD+ will stop. Aerobic Respiration will stop.

Electron Transport Chain and Oxidative Phosphorylation

Purpose: uses the energy in NADH and FADH2 to make ATP by Oxidative Phosphorylation = Chemiosmosis.

Electron Transport & ATP Synthesis

ETC: makes a H+ gradient = proton gradient. ATP Synthase: uses H+ gradient as a source of energy to make ATP.

Energy Conversion

1 NADH -> 3 ATP; 1 FADH2 -> 2 ATP.

Why do you make more ATP from NADH than from FADH2?

Electrons from NADH pass through 3 proton pumping steps -> a larger H+ gradient is made -> 3 ATP/ NADH. Electrons from FADH2 only pass through 2 proton pumping steps -> smaller gradient made -> only 2 ATP/ FADH2.

Aerobic Respiration: Net Energy Yield per Glucose (Detailed)

Glycolysis: 2 ATP+(23=6ATP); Import into Mt.: +(23=6ATP); Krebs Cycle: 2 ATP+(63=18ATP)+ (22=4ATP). Total=4 ATP +30 ATP +4 ATP = 38 ATP.

No Free Shipping!

Moving 2 NADH into Mitochondria costs 1 ATP/ NADH. 2 NADH made in cytoplasm move into Mitochondria. Net Gain in ATP: 38 ATP max - 2 ATP shipping = 36 ATP.

Alcohol Fermentation

In: Plants, Fungi, Some Bacteria. Uses up 2 NADH! No ATP or O2 made!

Lactic Acid Fermentation

In: Animals, Some Bacteria. Uses up 2 NADH! No ATP or O2 made!

Anaerobic Respiration: Net Energy Yield per Glucose

Glycolysis: 2 ATP + 2 NADH; Fermentation: -2 NADH; Net Energy Gain: 2 ATP.

Purpose of Fermentation Reactions

NO O2! Converts NADH back to NAD+, Glycolysis continues.

Metabolism of Food Molecules

Carbohydrates, Fats = Triglycerides, Proteins.

FOOD DIGESTION: Carbohydrates

Starch -> glucose; Disaccharides -> C6 sugars -> Enter at beginning of Glycolysis.

FOOD DIGESTION: Fats

Triglycerides -> Glycerol C3 + 3 Fatty Acids; Glycerol C3 -> G3P C3 Enter at middle of Glycolysis.

FOOD DIGESTION: Proteins

Proteins -> Amino Acids; NH2 removed from AA by deamination.

Reactions to Memorize: Import into the Mitochondria

Pyruvate (C3) + CoA + NAD+ -> Acetyl CoA (C2) + CO2 + NADH.

Reactions to Memorize: 1st Reaction Krebs Cycle

Acetyl CoA (C2) + Oxaloacetate (C4) -> Citric Acid (C6) + CoA.

Reactions to Memorize: Fermentation: Animals

Pyruvate(C3) + NADH -> Lactic Acid(C3) + NAD+.

Reactions to Memorize: Fermentation: Plants, Fungi

Pyruvate(C3) -> Acetaldehyde(C2) + CO2; Acetaldehyde(C2) + NADH -> Ethanol(C2) + NAD+.