cellular respiration
DESCRIPTION
Cellular Respiration. Glucose Metabolism 9.10. The point is to make ATP Moving H-atoms…..moves energy from one molecule to another Oxidation/ReductionOIL RIG *Coupled ReactionsLEO GER Oxidized?Reduced?. 3 Main Principles:. Glucose Oxygen. - PowerPoint PPT PresentationTRANSCRIPT
Glucose Metabolism 9.10
*Cellular Respiration
*3 Main Principles:
1.The point is to make ATP
2.Moving H-atoms…..moves energy from one molecule to another
3.Oxidation/ReductionOIL RIG *Coupled Reactions LEO GER
Oxidized? Reduced?
RESPIRATION: Process by which cells generate ATP through a series of redox reactions. Converting food energy* (C6H12O6) into ATP. *Need ATP for some coupled reactions…(*Proteins, Lipids, Nucleic acids, Other Carbohydrates).
Glucose Oxygen
1. GLUCOSE is Broken down
2. Occurs in steps
3. Bond energy is released as ATP + HEAT
4. Small amounts of energy released at each step…controlled by enzymes (reaction rate)
5. Occurs CONSTANTLY
WHY IN STEPS?
FOUR STAGES (notes)
*GLYCOLYSIS
*FORMATION OF ACETYL CoA
*CITRIC ACID (KREBS) CYCLE
*ELECTRON TRANSPORT CHAIN
*TWO MAIN TYPES:
Cellular Respiration Fermentation Mitochondria/ETC Cytosol/Cytoplasm
*Does NOT require oxygen (Can be aerobic or anaerobic)
*Requires: ATP, ADP, NAD+
*TWO PHASES: Endergonic & Exergonic “Investment - Capture”
*1 Glucose
2 pyruvate (2-3C)
NET 2 ATP, 2 NADH
(2 G3P)
*Oxidation of NAD+ to NADH
3 steps: Kinase: Phosphorylation of
glucose *More chemically Active
Isomerase (Glucose 6P to
Fructose6P) Kinase: 2nd
Phosphorylation
Fructose6P to Fructose
1,6P)2 more steps: Split, Isomerase
One Step: Gain of H (NAD+ to NADH) Powers Gain of Pi (Inorganic Phosphate)*Inorganic phosphate in
cytoplasm
Last 4 Steps: Kinase…Substrate Level Phosphorylation * ADP to ATP
5 steps
5 steps
*NADH*NAD+ + 2H
H = e- p+
H = e- p+
NAD+ + e- = NAD + H (e- and p+) = NADH
“Energy on Hold”
*Substrate Level Phosphorylation
ATP is formed by the direct transfer of a phosphate group from a high-energy substrate (Glycolysis) in an exergonic catabolic pathway to ADP
Powering the Electrochemical gradient
CRAvailable O 2
Purpose: Regenerates NAD+ for glycolysis
*Oxidative Decarboxylation
1. Remove a carboxyl group COOH (Decarboxylation, as CO2 and H)
2. Oxidize the 2C fragment, 2NAD+ is reduced to 2NADH- - - - ETC
3. Coenzyme A ‘transport molecule’ is attached to the acetyl group
The S-C bond can be broken, Acetyl group (2C X 2) enters Krebs)
Formation of Acetyl CoA from Pyruvate (3C) “The Escort” Intermembranal Area of the Mitochondria
STEPS:
*TOTAL ENERGY SO FAR:
4 NADH (2 Glycolysis, 2 formation of acetyl CoA)
2 ATP (From Glycolysis)
*Oxidative Decarboxylation
* CITRIC ACID CYCLE (TRICARBOXYLIC-TCA)
* Mitochondrial Matrix
* 5 steps
* TWO Cycles/Glucose
* YIELD: (per Glucose)
4 CO2
2 ATP
6 NADH
2 FADH2
1. 4C + 2C = 6C
Oxaloacetic
+ Acetyl = Citric Acid
2. 2 CO2 removed/cycle
(4/glucose) Decarboxylation
3. Substrate level Phosphorylation, 2 ATP/Glucose
4. OA4C > 6C > 5C
> 4C > 4C > OA4CPer Glucose: 4 CO2, 2 ATP
6 NADH, 2 FADH2
“Energy On Hold”
STEPS/YIELD
KREBS
*ELECTRON TRANSPORT CHAIN
• Protons (H+) move across I, III and IV (Each electron moves 1 H out).
• One NADH…2 e- From I to IV…6 H+ out of matrix (At V- can get 1 ATP/2 H+)
(Inner membrane NOT permeable to NADH; glycolysis count is different)
• One FADH2…2e- from II to IV…4 H+ out of matrix……eventually 2 ATP
• Electrons fall to successively lower energy levels as carriers are reduced/ oxidized…moving H+ and resulting in the oxidative phosphorylation of ATP
• Protons re-enter the matrix at V with ATP synthase enzyme; chemiosmosis
• Final electron acceptor is Oxygen, + 2P, produces H2O (No O2, No ETC)
*NET ENERGY YIELD: Cellular Respiration
*NADH From Glycolysis
*NADH from Glycolysis: In Liver, Kidney, Heart- 3ATP; Skeletal muscle, brain- 2 ATP
1 mol glucose burned- 686kcal released as heat. 36-38 ATP G is ~274kcal 274/686 40% efficient