Biochemistry Of Exercise Flashcards
What is the main energy carrier molecule in cells?
ATP
How does ATP release its energy
In the presence of ATPase and water:
ATP—> ADP+P +energy
What is the phosphocreatine pathway, PCr?
Cells contain a small amount of PCr, creatine kinase acts on this to release a phosphate and energy which can be used to make ATP.
It is a form of substrate level metabolism
Anaerobic
Can sustain energy for up to 15 seconds in full sprint
What is anaerobic glycolysis?
ATP production from glucose breakdown in the cytoplasm
Glucose –> glucose 6 phosphate–>multiple reactions–> pyruvate
It releases 2 ATP per glucose molecule
Pyruvate is converted into lactate if it is not metabolised and used in the krebs cycle
What kind of exercise is anaerobic glycolysis used in?
Short intense exercise eg 400 sprint
What is oxidative phosphorylation
Fatty acids or pyruvate are converted into acetyl co A.
Acetyl co A enters the krebs cycle
The krebs cycle creates ATP but also feeds the electron transport chain
This process ultimately releases 38 ATP per molecule of glucose
It requires oxygen and releases carbon dioxide and water
What happens when carbohydrate resources expire ?
Fat can be used as fuel when there are no carbs left, this is much slower as fatty acids need to be generated via beta oxidation, but energy yield per molecule is much greater
What are the key interacting molecules in skeletal muscle contraction ? How do they contract?
Actin and myosin. During contraction binding sites on actin are exposed by calcium ions, myosin binds. ATP then binds which forms a cross bridge stroke of myosin on a actin leading to further contraction
How does muscle contraction occur ?
Binding sites on actin are exposed by calcium ions. Myosin binds followed by ATP which enables a cross bridge stroke of myosin on actin, leading to contraction.
What is a type 1 muscle fibre ?
Slow twitch- it has lots of mitochondria and a rich blood supply so uses mainly oxidative phosphorylation. It does not fatigue easily but produces loee forces. It is used in endurance exercise
What is a type 2a muscle fibre ?
Fast twitch oxidative. Lots of mitochondria, highly oxidative, high glycolytic capacity. Used in exercise like weight lifting.
What is a type 2b muscle fibre ?
Fast twitch glycolytic- few mitochondria, fatigues easily. Used in exercise like sprinting
How is skeletal muscle structured?
Actin and myosin–> one unit makes a sarcomere. A long line of sarcomeres makes a filament. Filaments are arranged into myofibrils which in turn are collected into fibres.
A group of fibres is surrounded by endomysium to form a fascicle
A group of fascicles is surrounded by perimysium to form muscle.
