Cellular Trasport

Question 1

Define passive process

Answer 1

• Cells energy
• Comes from respiration
• Does not have to be used

Question 2

Define active process

Answer 2

• Require the cells energy for the transfer to occur

Question 3

Define diffusion

Answer 3

The spreading out of particles so that they are evenly distributed over the space available.

• High - low concentration
• Occurs in gases and liquids because the molecules are constantly moving

Question 4

Describe the motion of particles in a liquid or gas as diffusion takes place

Answer 4

They move in random directions and in straight line until they hit another molecule or the wall of the container

Question 5

Define Diffusion gradient

Answer 5

• The difference in concentration that brings out diffusion

- Can also be called concentration gradient

Question 6

How would alcohol move through the cell membrane

Answer 6

Easily enter cells because they can diffuse through the lipid proteins

Question 7

How would oxygen move through the cell membrane

Answer 7

• Diffuses through the phospholipid bilayer

- It is continually used up

Question 8

How would water move through the cell membrane

Answer 8

Must pass through a channel protein

Question 9

What factors may determine the speed that diffusion takes place

Answer 9

• Temperature

- Concentration

Question 10

Define osmosis

Answer 10

Diffusion of a solvent through a differentially permeable membrane
- High - low concentration

Question 11

Osmosis commonly involves which compound

Answer 11

Water

Question 12

Define carrier-mediated transport

Answer 12

Transport across the cell membrane using special proteins called carrier proteins.

• Can be an active process (active transport)
• Can be a passive process (facilitated diffusion)

Question 13

Define facilitated diffusion

Answer 13

This is the movement of specific molecules down a concentration gradient, passing through the membrane via a specific carrier protein.

• Passive process
• Each carrier has its own shape and allows one molecule to pass through

Question 14

Compare and contrast diffusion and facilitated diffusion

Answer 14

Different:
- They have channel proteins (2 for facilitated, 1 for diffusion)
- The channel proteins involved in facilitated are specific
Similar
- Passive processes
- Go from high - low concentration
- Needs proteins

Question 15

Define active transport

Answer 15

The energy-demanding transfer of substances across a cell membrane against its concentration gradient
- Low - high concentration

Question 16

Examples of active transport

Answer 16

• Re-absorption of glucose, amino acids and salts by the proximal convoluted tubule of the nephron in the kidney
• Sodium/potassium pump in cell membranes

Question 17

Compare and contrast facilitated diffusion and active transport

Answer 17

• Facilitated and active transport both use carrier proteins
• Active needs energy, facilitated doesn’t
• Concentration gradient is different
  Active: low - high
  Facilitated: high - low

Question 18

Define vesicular transport

Answer 18

The movement of substances into and out of cells enclosed in vesicles

• Active process
• Move bulk quantities of solid or liquid particles

Question 19

Endocytosis

Answer 19

• Cell membrane surrounds some extracellular material
• Forms a vesicle
• Vesicle is taken into the cell

Question 20

Types of endocytosis

Answer 20

• Phagocytosis (cell eating)

- Pinocytosis (cell drinking)

Question 21

Exocytosis

Answer 21

• Removing substances from the cell using vesicles

- Can be used to get rid of wastes

Question 22

Examples of exocytosis

Answer 22

• Digestive enzyme
• Milk from breast cells
• Saliva from salivary gland cells