Week 6: ATP. Aerobic metabolism and endurance sport Flashcards
What does the ability to sustain a high intensity activity without becoming fatigue depend on?
Acquisition, transport and delivery of oxygen
Metabolic capacity of specific muscle cells to generate ATP aerobically
centrally and peripherally limited factors
V02- limited centrally
peripherally limited factors- in muscles
Exercise during and intensity
Decrease in speed and energy demand is gradual as duration becomes longer
All out exercise lasting about 75 seconds= 50% aerobic and 50% anaerobic
About 25% of Wingate type effort comes from aerobic mechanisms
Marathon fuel
Carbohydrate diven
Creatine phosphate an aerobic mechanisms also involved during tactics at the start and the end
Muscle glycogen- trickle of glucose in blood which liver produced which can be used as fuel
Oxygen used in mitochondria
Mitochondira are abundant cells that consume oxygen
Oxidation of carbohydrates
Blood glucose- from the liver, ingested carbohydrate
Muscle glycogen
Carbohydrate (from liver, muscle glycogen, what we’ve eaten) covered to pyruvate by glycolysis aerobically
Lipids next to mitochondria
Only pathway you can use lipids is aerobic
Private enters mitochondria and TCA cycle
Oxidation of fat
Free faty acids from adipose tissue and some intramuscular fat
Fat has to be oxidised to be sed
2 carbon units sequentially removed from FFA via beta oxidisation to generate acetylene coA
Aceytl co A enters TCA cycle
Control of Krebs
Glycolysis connects with Krebs
2 enzymes achieve opposite aims in conflict
If you can increase the rate of the enzymes, balance the pyruvate and dehydrogenase
Pyruvate dehydrogenase has 2 forms- one active and one inactive
More calcium concentration outside sarcoplasmic reticulum activated pyruvate dehyrodgenase
Increased concentrations of pyruvate indicating glycolysis has sped up, pyruvate switches off the enzyme which switches off pyruvate dehydrogenase
Electron transport
Hydrogen atoms removes from metabolites by dehydrogenation are picked up by the coenzymes NAD plus FAD co enzymes
Co enzymes transfer the H atoms on to the electron transport chain
Hydrogen atoms passed to oxygen which traps some of the energy liberates
Hydrogen ions actively piped out of the mitochondria which creates a concentration gradient of hydrogen ions across the inner mitochondria membrane
Where is the electron transport chain?
Inner membrane of the mitochondria
Lactic acid
Lactic acid is produced from glycogen in muscle when insufficient oxygen is supplied. Muscle fibres have a low capacity to use oxygen
Phosphocreatine breakdown
Some of the energy for ATP resysntheis is rapidly without the need for oxygen
When PCr is broken down to creatine and P by the action of the enzyme creatine kinase, a large amount of energy is released
Resynthesis of ATP through breakdown of PCr buffers some of the hydrogen ions formed as the results of ATP hydrolysis
GLUT 4
A specific transporter protein which carries glucose molecules across the saecollemal membrane