Bioenergetics Flashcards
ATP-PCr System
ATP is constantly being used and needs to be resynthesized
PCr (phosocreatine)
ADP can be used the PCr to resynthesize ATP - helps sustain it for a longer period of time
Intracellular source of “bond” energy to rebuild ATP
Limited capacity system - 3-15 sec but quick
Anaerobic pathways to make ATP
PCr and Glycolysis - PCr is fastest
They can be performed in relative absence of O2
Aerobic pathways to make ATP
CHO and Fat - Fat will give you most energy
They require oxygen - use ETC
ATP pathways are dependent on…
Intensity and duration
Short term, High intensity activities
Greater contribution of anaerobic energy systems
Long term, Low to moderate intensity exercise
Majority of ATP produced from aerobic sources
Glycolysis
Start with glucose or glycogen, Need ATP and then —>
ATP NADH and Pyruvate –>
Pyruvate with no O2 will produce lactate
Pyruvate with O2 will go through ETC path to mitochondria
Overview of Glycolysis
Rate Limiting Step
Breakdown of glucose or glycogen
11 enzymatic rxns - occur in cytoplasm or sarcoplasm
Rate Limiting = Phosphofructokinase
Gross Products of Glycolysis
4 ATP
2 NADH (to ETC)
2 Pyruvate
Net Products of Glycolysis
2 ATP
2 NADH (to ETC)
2 Pyruvate
If no O2 what are products from glycolysis
2 ATP
2 Lactate
NADH used to form lactate
Net products if start with glycogen
3 ATP
2 NADH
2 Pyruvate
Conversion of Pyruvic Acid to Lactic Acid uses what enzyme
Lactate dehydrogenase
Fate of Pyruvate with no O2 present
Lactate Production
Fate of Pyruvate with O2 present
PDH - pyruvate dehydrogenase - ETC
PC - pyruvate carboxylase (supports fat metabolism)
Pyruvate –> Acetyl CoA
1 NADH
1 CO2
Krebs Cycle (1 turn - 1 Pyruvate)
Acetyl CoA + OAA –> citrate
Location = matrix
Products = 1 FADH2, 3 NADH, 1 GTP, 2 CO2
Electron Transport Chain
Location = inner mitochondrial membrane Products = 2.5 ATP/NADH, 1.5 ATP/FADH2, H20
Rate Limiting step in Kreb Cycle
Isocitrate Dehydrogenase
Total (net) ATP produced from one glucose molecule
32
Where does beta oxidation occur
mitochondrial matrix
What does each beta oxidation give you
1 FADH2
1 NADH
1 Acetyl CoA
For every Acetyl CoA what happens
1 turn of Kreb cycle
Total (net) ATP production from C16H32O6
106
Caveat - what do you need to bind to Acetyl CoA
OAA - you need enough OAA so you can keep turning the cycle
How does Pyruvate know which way to go in presence of oxygen
Allosteric Regulation
Allosteric Modulation
Rate limiting enzymes - can act as feedback inhibitors and limit it at rate limiting step
High ATP will do what to allosteric pathways
Inhibit
High ADP will do what to allosteric pathways
stimulate
Rate Limiting Step ATP-PCr
Creatine Kinase
Rate Limiting Step Glycolysis
Phosphofructokinase
Rate Limiting Step of Kreb
Isocitrate Dehydrogenase
Rate Limiting Step of ETC
Cytochrom Oxidase
Allosteric Modulation is a way of regulating…
- Method for controlling rate
2. Control whether goes down PDH path (if build up of OAA) or down PC path (build up of Acetyl CoA)
