Transport In Cells

Question 1

What is endocytosis

Answer 1

The bulk uptake of substances into a cell by engulfing it with the cell membrane to form a vesicle(membrane bound sacs, in endocytosis these are created from the cell surface membrane) trapping the substances inside the cell with the use of energy in form of ATP

Question 2

What is exocytosis

Answer 2

The bulk transport of substances out of a cell using a vesicle(membrane bound sac) that fuses with the cell surface membrane using energy in form of ATP, releasing content of vesicle

Question 3

Role of channel proteins

Answer 3

allow large/polar molecules and ions to pass through the cell membrane as the hydrophobic tails of the phospholipid bilayer form an impenetrable layer

Question 4

What is osmosis and does it require energy

Answer 4

The net movement of water molecules through a semi-permeable membrane from an area with low solute concentration to an area of high solute concentration
-does not require energy=passive process

Question 5

Type of channel protein which can assist with large water volumes

Answer 5

Aquaporins

Question 6

What is a hypertonic solution

Answer 6

The solution with a higher solute concentration than the solution on the other side

Question 7

What is a hypotonic solution

Answer 7

The solution with a lower solute concentration than the solution on the other side
-think hypo, rhymes with low

Question 8

What is an isotonic solution

Answer 8

Solution with the same solute concentration as solution on the other side

Question 9

What is facilitated diffusion and does it require energy

Answer 9

Channel/carrier proteins facilitate diffusion across cell membrane, moves polar/large molecules which cannot simply diffuse across cell membrane due to barrier of hydrophobic fatty acid tails
-does not require energy so movement is from higher concentration to lower concentration of molecule being transported

Question 10

What are gated channels

Answer 10

Can be opened or closed depending on the presence of a signal(hormone/change in pd across membrane)

Question 11

What are carrier proteins and which direction does movement occur

Answer 11

Ion/molecule binds to specific site on protein, protein changes shape and as a result ion/molecule crosses membrane
-molecule move from higher to lower concentration due to more frequent binding to carrier protein on side with higher concentration of molecule being transported

Question 12

What is diffusion and does it require energy

Answer 12

-net movement of particles from an area of their high concentration to an area of their low concentration
-does not require energy=passive

Question 13

Which particles can diffuse across the cell membrane without the need for a channel/carrier protein

Answer 13

-small non polar particles can diffuse directly across cell membrane
-eg water(polar however size allows them to diffuse rapidly), carbon dioxide, oxygen

Question 14

How is glucose transported into cells

Answer 14

-through GLUT transporter to be used for respiration in mitochondria

Question 15

Two ways ions can be transported through cell membrane

Answer 15

-ion channel(passive and cannot control exact concentrations of each ion)
-protein pump(used active transport to ensure ion concentration is exactly correct)

Question 16

When does osmosis stop happening

Answer 16

When solutions are isotonic, concentrations of solute equal on both sides of partially permeable membrane

Question 17

What is active transport and does this require energy

Answer 17

The movement of particles from an area of their low concentration to an area of their high concentration(against the concentration gradient)
-requires energy (active process) from ATP

Question 18

Where does active transport occur

Answer 18

Through carrier proteins which change shape due to specific molecules they transport binding to them

Question 19

Where does the energy for active transport come from and how is this formed

Answer 19

ATP, made up of three phosphates and when the bond with the third phosphate breaks it releases a lot of energy