Cell Biology 1.4

Question 1

diffusion

Answer 1

is the passive movement of particles from a region of high concentration to low concentration

Question 2

simple vs facilitated diffusion

Answer 2

s. diffusion: does not require a protein channel
f. diffusion: requires a protein channel

does not require energy, substances move down a concentration gradient

Question 3

active transport

Answer 3

opposite from diffusion. substances move against the concentration gradient. requires energy + protein pumps

Question 4

osmosis

Answer 4

passive movement of water molecules across a permeable plasma membrane, from a region of low solute to high solute concentration

Question 5

endocytosis

Answer 5

uptakes substances by the cell.

1) membrane sucks the substance in, forming a pit which encloses the particle
2) membranes moves due to its fluidity
3) energy is required to change its shape
4) membrane seals back and the edges fuse together
5) vesicles breaks away from the plasma membrane and moves with the cytoplasm
6) particle enters the cell cytoplasm, enclosed by a vesicle
7) inner phospholipid layer of the plasma membrane becomes the outer layer of the vesicle membrane. outer phospholipid layer become inner layer of vesicle membrane

Question 6

exocyotisis

Answer 6

release substances by the cell

1) vesicles carries material through the cytoplasm to the plasma membrane
2) phospholipid bilayer join together
3) membrane flattens
4) vesicle fuses with plasma membrane
5) the material is released from the cell
6) neurones also releases neurotransmitters