comparing diffusion, osmosis and active transport

Question 1

which method(s) are passive?

Answer 1

osmosis and diffusion

Question 2

how do cells get the energy for active transport?

Answer 2

from the mitochondria, from respiration

Question 3

does each method require a membrane?

Answer 3

at: yes-occurs over a membrane, so requires carrier proteins
o: yes-occurs over a partially permeable membrane
d:no

Question 4

how do the concentration gradients differ?

Answer 4

at: substances move against the concentration gradient (low to high)
o: water moves down the concentration gradient (high to low)
d: substances move down the concentration gradient (high to low)