muscles

Question 1

sliding filament theory

Answer 1

1- when not contracting, tropomyosin blocks the binding site (for myosin head) on actin filament
2-when action potential reaches muscle, Ca2+ are released (from sarcoplasmic reticulum). Ca2+ bind to troponin which changes shape and moves tropomyosin from binding site.
3-myosin head binds and change position, sliding actin over myosin
4- ATP binds to myosin head to detach it from binding site. The ATP is hydrolysed and myosin head returns to original position.

Question 2

where does ATP come from

Answer 2

-aerobic respiration (oxidative phosphorylation)
-anaerobic respiration (glycolysis)
-phosphocreatine- provides phosphate to ADP in anaerobic conditions to produce ATP rapidly.