Transport of materials across plasma membrane

Question 1

What are the two types of passive transport?

Answer 1

Simple diffusion and facilitated diffusion

Question 2

Does passive transport require any energy to occur?

Answer 2

No, it doesn’t

Question 3

Give three examples of molecules that participate in simple diffusion

Answer 3

1. O2
2. CO2
3. Non-polar molecules

Question 4

Give three examples of molecules that participate in facilitated diffusion

Answer 4

1. ionic (charged) polar molecules
2. water
3. glucose

Question 5

Which transport moves molecules from a low concentration outside of cell to a high concentration inside of cell?

Answer 5

Active transport

Question 6

Which transport moves molecules from a high concentration outside of cell to a low concentration inside of cell?

Answer 6

Passive transport

Question 7

Which type of transport requires energy?

Answer 7

Active transport

Question 8

How does active transport get larger ions/metabolites into a cell?

Answer 8

Using carrier proteins and cell channels

Question 9

Define diffusion

Answer 9

the net movement of molecules down a concentration gradient, allowing small molecules to cross the plasma membrane

Question 10

What molecule defuses through a plasma membrane through osmosis?

Answer 10

Water

Question 11

What does it mean if the concentration of solutions on both sides of the membrane are equal?

Answer 11

the solutions are isotonic

Question 12

Osmosis Definition:

Answer 12

net diffusion of water across a membrane towards a HIGHER solute concentration

Question 13

What is a hydration shell?

Answer 13

water molecules that surround the charged solute molecules

Question 14

In osmosis, would the side with the higher or lower solute concentration contain more free water molecules?

Answer 14

lower solute concentration has MORE free water molecules, as the higher side has more water molecules in HYDRATION SHELLS

Question 15

In osmosis, what is a hypertonic solution?

Answer 15

a solution with a HIGHER solute concentration

Question 16

In osmosis, what is a hypotonic solution?

Answer 16

a solution with a LOWER solute concentration

Question 17

What are aquaporins and what do they do?

Answer 17

channels in the cell membrane which regulate water in the cell; facilitate osmosis

Question 18

What stops ions entering an aquaporin channel?

Answer 18

a charged section in the middle of the channel

Question 19

What happens to red blood cells in hypertonic solution?

Answer 19

Become shrivelled as water moves out of cell

Question 20

What happens to red blood cells in hypotonic solution?

Answer 20

Become swollen and will eventually burst as water moves into the cell

Question 21

Which solution do animal cells need to be in? Hypertonic, Isotonic or Hypotonic?

Answer 21

Isotonic

Question 22

What is active transport?

Answer 22

Active transport uses energy (ATP) to move materials against a concentration gradient

Question 23

What are the three carrier proteins used in active transport?

Answer 23

Uniporters, symporters and Antiporters.

Question 24

What is cotransport?

Answer 24

When both molecules are moving in the same direction across the membrane and the transporter is a symporter.

Question 25

What is counter-transport?

Answer 25

the inwards movement of Na+ is coupled with outward movement of another substance, like Ca2+ or H+

Question 26

What is endocytosis?

Answer 26

a process which allows bulk transport of molecules INTO the cell

Question 27

What is exocytosis?

Answer 27

Removes substances out of cell in bulk

Question 28

Name 3 examples of endocytosis.

Answer 28

Phagocytosis; Pinocytosis and Receptor-mediated endocytosis