Metabolism 1 Flashcards
Mastery
Contribution of energy systems
when does lipolysis happen and glycolysis
ATP turnover during 30s of all out cycling
first 6 seconds, creatine phosphate
then anaerobic glycolysis
then aerobic
Immediate energy system
PCr breakdown
replenish?
how long?
PCr during heavy exercise and ATP
Stored ATP and Phosphocreatine in the muscle
break the ATP bond to make energy
Fastest and simplest energy
does not need oxygen, substrate level
PCr breakdown releases 10.3kcal/per mol
- more than needed to replenish ATP
PCr is only enough for 8-13 seconds max effort
an Aerobic glycolytic pathway
how much ATP
lactate acid as intensity goes up
involves the breakdown of glucose or glycogen
goes thru GLUT 4 transport protein
become G6-P
then pyruvate
glycogen becomes G6-P
the end product is lactate
1 ATP thru GLUT 4, 1 ATP from G6-P
glycolysis produces 2 ATP, glycogenolysis 3 ATP
aerobic pathway timing
oxygen needs
what is used
limitations
lactate and what is the muscle fatigue
Predominates during early stages (e.g., 1-2 minutes) of
high-intensity exercise
* Does not require oxygen
* Carbohydrate is the only macronutrient that can
generate ATP anaerobically
* Blood ~5 g
* Muscle ~500 g
* Liver ~80 g
* Limitations:
* Does not produce a large amount of ATP
* Produces H + ions
* H + reduces blood and muscle pH and results in muscle
(peripheral) fatigue
* Lactate is a fuel – it can convert to glucose
(gluconeogenesis) and produce energy
Aerobic pathway.
processes
what does it involve
where
energy production
Involves 3 main processes:
* Aerobic glycolysis
* Krebs cycle (TCA/Citric acid cycle)
* Electron transport chain
* Involves cellular respiration because oxygen is required
* Occurs inside the mitochondria
* Number and density of mitochondria determine the aerobic
capacity of that muscle
* Denser near capillaries to optimize O2 delivery
* Aerobic pathway has a large energy production
capacity
how does pyruvate get converted
when O2 is available
into the Krebs cycle
what does krebs cycle produce
ETC
Pyruvate gets converted to acetyl-CoA in the
mitochondria
* Irreversible step
* Acetyl-CoA will enter the Krebs cycle
* Combined with NAD+ and FAD will produce ATP, NADH, and FADH 2
2ATP, 6NADH, 2FADH, and OXALOACETATE
NADH and FADH2 carry electrons to ETC, electrons are passed thru channels and the hydrogen gradient causes H+ to go back into the mitochondria thru ATP synthase which makes ATP
ATP yield from aerobic glycolysis
1 NADH + H + is worth 2.5 ATP
* 1 FADH 2 is worth 1.5 ATP
Glycolysis (before entering mitochondria):
* 2 ATP
* 4 NADH = 10 ATP
Krebs cycle:
* 2 ATP
Oxidative phosphorylation:
* 6 NADH = 15 ATP
* 2 FADH 2 = 3 ATP
Total yield:
4 ATP
10 NADH (25 ATP)
2 FADH2 (3 ATP)
Contrast this with
anaerobic glycolysis
