Bioenergetics Flashcards
ATP and the PCr system
PCr keeps ATP around longer for the beginning of exercise
PCr + ADP Cr + ATP….converts with creatine kinase enzyme
Type of oxygen availability during shot-term high-intensity exercise?
Anaerobic energy systems
example: ATP- PCr system
Type of oxygen availability during long-term low to moderate-intensity exercise?
Aerobic sources
example: Oxidative phosphorylation
Immediate energy source?
ATP-PCr system
Anaerobic pathway
Short-term energy source?
Glycolysis
Anaerobic Pathway
Long-term energy source?
Aerobic/Oxidative phosphorylation/ ETC
Glycolysis
Breakdown of glucose or glycogen
Beginning steps of the Kreb’s cycle
Final products produced from reaction: 2 pyruvate or lactate, 2 ATP (had 4 but used 2 during reaction), 2 NADH,
What happens if not enough oxygen is available?
Form lactate instead of pyruvate
One fate of pyruvate!!
What enzyme is used to convert pyruvic acid to lactic acid?
Lactate dehydrogenase (LDH)
What are the fates of pyruvate?
All occur in the matrix of the mitochondria
- Produce lactate when oxygen is not present
- Produce Pyruvate Carboxilase (PC)
- Produce Pyruvate Dehydrogenase
Pyruvate Dehydrogenase
The enzyme that converts pyruvate to Acetyl CoA which enters the Kreb’s cycle
Where does glycolysis occur?
cytoplasm
NOT the mitochondria
How many turns of the Krebs Cycle does the break down of glucose yield?
2 tuns b/c produced 2 pyruvate which produced 2 Acetyl CoA
What is produced from1 turn of the Krebs Cycle?
1 GTP, 3 NADH, 1 FADH2, 2 CO2
1-3-1 rule
Where does the Krebs Cycle take place?
Matrix of the mitochondria
What is produced from the ETC?
2.5 ATP per NADH
1.5 ATP per FADH2
Water
Rate Limiting Step
Step with the highest amount of energy that needs to be overcome
Example: In glycolysis: PFK is rate limiting enzyme (phosopfructokinase)- important because: PFK affected, glycolysis affected
Kreb’s Cycle Steps
2 pyruvate –> release 2 NADH2 and 2 CO2 –> PDH converts 2 Acetyl CoA –> combines with OOA –> Citrate
Gain 1 GTP, 3 NADH, 1 FADH2 and 2 CO2
What is Beta Oxidation?
Catabolism of fatty acids in the mitochondria matrix to Acetyl CoA
Fats require more oxygen to burn
Carnitine
Transfers fatty acids to mitochondria matrix for Beta Oxidation
What does Oxaloacetate (OOA) require?
Carbohydrates to keep it filled with 4 carbons so Acetyl CoA can bind for fat metabolism (Pyruvate carboxylase important in this step)
What are the products from Beta Oxidation per round?
1 Acetly CoA, 1 FADH2, 1 NADH
Take each product times its respective ATP number
Get over 100 ATP from 1 mole of fat
Rate Limiting Enzymes
Allosteric Modulation - control rate of metabollic pathway
1. ATP-PCr = creatine Kinase
2. Glycolysis = Phosphofructokinase
3. Krebs Cycle = Isocitrate Dehydrogenase
4. ETC = Cytochrome Oxidase
Example: Stimulate PFK –> produce more pyruvate
Oxygen Availability
- Sufficient O2 – pyruvate enters mitochondria (aerobic)
2. Insufficient O2- pyruvate converts to lactate in sarcoplasm (anaerobic)
What inhibits the Krebs Cycle pathway?
- Products of metabolic pathways can act as feedback inhibitors (citrate, ACoA, pyruvate)
- High ATP inhibits pathways
- High ADP or AMP would stimulate pathway
Allosteric Modulation
Too much NADH will inhibit different areas around the Kreb’s Cycle
Too much Citrate will inhibit the citrase enzyme
