Transport Across Membranes

Question 1

Facilitated diffusion

Answer 1

Passive transport of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient, through transport proteins, across a biological membrane.

Question 2

Channel protein

Answer 2

• ions or very small molecules

- open or close

Question 3

Carrier protein

Answer 3

• A molecule attached to the binding site of the protein.

- Protein changes its configuration and releases the molecule to the other side of the plasma membrane.

Question 4

Osmosis

Answer 4

The net movement of water molecules from a region of less negative water potential to a region of more negative water potential across a partially permeable membrane.

Question 5

Diffusion and osmosis SIMILARITIES

Answer 5

1) both processes are passive and do not require energy form metabolism
2) both processes only occur in the presence of a gradient

Question 6

Diffusion and osmosis DIFFERENCES

Answer 6

1) Osmosis refers to the net movement of water molecules only while diffusion refers to the net movement of any type of particles
2) Osmosis only occurs in the presence of a partially permeable membrane while diffusion does not require a membrane.

Question 7

Active transport

Answer 7

The prices in which energy is used to move particles from a region of lower concentration to a region of higher concentration against a concentration gradient.

Question 8

Facilitated diffusion and active transport SIMILARITIES

Answer 8

1) They both only occur in living cells
2) They both require membrane proteins
3) they both require a gradient

Question 9

Facilitated diffusion and active transport DIFFERENCES

Answer 9

1) Active transport requires energy from cellular respiration while facilitated diffusion does not.
2) Facilitated diffusion is the movement of substances down a concentration gradient while active transport is the movement of substances against a concentration gradient

Question 10

Endocytosis

Answer 10

Is a cellular whereby cells absorb large materials from the outside of the cell by engulfing them in a membranous vesicle.

Question 11

Exocytosis

Answer 11

Cellular process whereby cells eject large molecules, such as waste products, from the interior of the cell via a membranous vesicle.

Question 12

Diffusion

Answer 12

Net movement of particles form a region of higher concentration to a region of lower concentration, down a concentration gradient.

Question 13

Concentration gradient

Answer 13

Difference in concentration between 2 regions