animal/plant responses

role of ATP in muscle contraction

• binds to myosin head

• breaks the myosin and actin cross bridge

• ATP hydrolysed to ADP to reset myosin head

• actively transporting calcium ions back to sarcoplasmic reticulum

role of hormones- gibberellins

• cause stem elongation and seed germination

• seeds absorb water

• gibberellins synthesised in the embryo

• amylase and protease synthesised which breaks down food stores

ABA

• stimulates stomatal opening and closure

• water becomes limiting

• root cells synthesise aba

• ABA is complementary to recpetors on cell membrane of guard cells

• ionic potential decreases, water potential increase

• water leaves by osmosis

auxins

• inhibit ethene

• maintains apical dominance