Sports Biology Flashcards
Why do muscles anaerobically respire even if oxygen is present in intense exercise?
Because anaerobic respiration is a quicker way to produce ATP
Why does anaerobic respiration quickly fatigue muscles?
Because of the build up of lactate
Produced when pyruvate is REDUCED to lactate
What is done with the lactate produced in anaerobic respiration?
Converted to pyruvate to be used in aerobic respiration so chemical energy locked in pyruvate is not wasted
How does build up of lactate cause muscle fatigue?
It lowers the pH
So alters H bonds and ionic bonds in proteins, changing tertiary structure (and active sites) in proteins so they are no longer complementary
Effect of build up of lactate on actin, myosin and tropomyosin
Less effective as they have changed shape so can no longer pull etc so prevents contraction
Effect of lactate build up on ATP hydrolase
The active site changes shape, so it is not complementary to its substrate ADP and Pi, preventing enzyme-substrate complexes forming to catalyse production of ATP which is needed in muscle contraction
Why does short, intense exercise favour anaerobic respiration?
Because it can produce ATP faster
Why does long endurance exercise prefer aerobic respiration?
Because 1 glucose produces 38 ATP which can last over a longer period
What does phosphocreatine do?
Phosphorylates 1 ADP to ATP
To form creatine
At rest, what does ATP do to creatine?
Phosphorylates it to phosphocreatine
What is phosphocreatine?
Found in muscle fibres to resist changes in ATP to a small extent
Eg a lot of ATP is used, it can Phosphorylate ADP to resist the using up of it
Types of muscle fibres
Fast and slow fibres
Fast fibres are used for…
Short distance running eg sprinting
Slow fibres are used for…
Long distance running eg marathons
Respiration: fast vs slow fibres
Fast fibres = anaerobic respiration
Slow fibres = aerobic respiration
Why are fast fibres better for short bursts of intense exercise?
Use mainly anaerobic respiration which produces ATP very quickly
Why are slow fibres better for endurance exercise?
Because they prefer aerobic respiration which produces much more ATP per glucose so will not be used up quickly, can last a long time
Slow/fast fibres: maintaining contractions
Slow fibres can maintain contractions for longer than fast fibres
Fast/slow fibres: speed of contraction
Fast fibres contract faster than slow fibres
Slow/fast fibres: numbers of mitochondria and capillaries
Slow fibres have a lot of mitochondria and capillaries
Fast fibres have less mitochondria and capillaries
Why do Slow fibres have lower numbers of glycolysis enzymes in cytoplasm than fast fibres?
Because glycolysis is used mainly in anaerobic respiration
But slow fibres favour aerobic respiration so do not need this many enzymes to anaerobically respire compared to fast fibres
Phosphocreatine concentrations: slow vs fast fibres
Slow fibres have lower concentration than fast fibres
Myoglobin concentration: slow vs fast fibres
Slow fibres have a higher concentration of myoglobin compared to fast fibres
Glycogen concentration: slow vs fast fibres
Slow fibres have a lower concentration compared to fats fibres
What is myoglobin?
A storage protein for oxygen found in muscle fibres NOT BLOOD
Myoglobin’s affinity to oxygen
Extremely high so only gives up oxygen at very low partial pressures
How does myoglobin prolong aerobic respiration?
Very rapid release of oxygen at very low partial pressures so this can prolong aerobic respiration: allows oxygen present
How does myoglobin delay anaerobic respiration
Because ensures oxygen is present for aerobic respiration
Myoglobin vs haemoglobin
Myoglobin has no cooperative binding unlike haemoglobin
Myoglobin = 1 polypeptide chain, haemoglobin = 4 polypeptide chain
Myoglobin has 1 haem group to hold 1 oxygen, haemoglobin has 4
Why do slow fibres have more myoglobin?
To prolong aerobic respiration to store oxygen
