Biosci E109 Final Ques ons and answers updated 2026
What affects the rate of diffusion?
concentra on gradient, temperature, molecule size
how are lipophilic molecules delivered into cells?
they need a messenger to carry them through because they aren't soluble
Explain what happens to a cell in hypertonic solu on
the cell has less solute concentra on so water moves out of the cell to the surrounding solu on
which causes the cell to shrivel
explain what happens to a cell in hypotonic solu on
water moves from the solu on into the cell due to higher solute concentra on. The cell
becomes lysed
explain what is meant by a synergism
when two drugs, etc are administered simultaneously and basically significantly amplifies the
effect of one another
what is an addi ve effect?
when 2 drugs, etc add to each others effect
explain the repolariza on of an ac on poten al
Na+ channels close and K+ channels open allowing the K+ channels to leave the cell and
become more nega ve
explain the depolariza on of an ac on poten al
once a threshold is reached, Na+ channels open allowing Na+ to enter the cell which makes the
cell more posi ve
explain the hyper polariza on in an ac on poten al
K+ channels close but K+ con nues to leak out of the cell making the cell even more nega ve
what is the refractory period of Na+ ?
Na+ channels cannot be s mulated or excited which prevents muscle contrac on from
happening
What affects the rate of diffusion?
concentra on gradient, temperature, molecule size
how are lipophilic molecules delivered into cells?
they need a messenger to carry them through because they aren't soluble
Explain what happens to a cell in hypertonic solu on
the cell has less solute concentra on so water moves out of the cell to the surrounding solu on
which causes the cell to shrivel
explain what happens to a cell in hypotonic solu on
water moves from the solu on into the cell due to higher solute concentra on. The cell
becomes lysed
explain what is meant by a synergism
when two drugs, etc are administered simultaneously and basically significantly amplifies the
effect of one another
what is an addi ve effect?
when 2 drugs, etc add to each others effect
explain the repolariza on of an ac on poten al
Na+ channels close and K+ channels open allowing the K+ channels to leave the cell and
become more nega ve
explain the depolariza on of an ac on poten al
once a threshold is reached, Na+ channels open allowing Na+ to enter the cell which makes the
cell more posi ve
explain the hyper polariza on in an ac on poten al
K+ channels close but K+ con nues to leak out of the cell making the cell even more nega ve
what is the refractory period of Na+ ?
Na+ channels cannot be s mulated or excited which prevents muscle contrac on from
happening
