Movement of substances into and out of cells

Question 1

What is diffusion

Answer 1

Net movement of particles from an area of higher concentration to an area of lower concentration. Down a concentration gradient

Question 2

when does net movement stop?

Answer 2

when equilibrium is reached

Question 3

Where does diffusion happen?

Answer 3

liquids, gases - particles are free to move randomly

Question 4

what type of process is diffusion?

Answer 4

passive process- ( no energy)

Question 5

why is diffusion good?

Answer 5

• useful substances that are used are replaced ( low conc)
• waste products do not build up

Question 6

what 3 factors affect diffusion

Answer 6

• Temp ( temp inc, KE of particles inc, move faster, more successful collisions
  -Concentration gradient -inc concentration, more particles to collide with each other and gas/liquid, faster diffusion
• Surface Area( inc SA of membrane, more amount of space for diffusion

Question 7

what gives high SA

Answer 7

folding of membranes

Question 8

adaptations of gas exchange surfaces ( 3 )

Answer 8

• being thin to reduce distance
  -large SA ( folding membranes)
  -Good blood/ air supply

Question 9

why is -Good blood/ air supply important?

Answer 9

for transportations + maintaining concentration gradient

Question 10

what does a high SA/Vol ratio show?

Answer 10

every part of an object is quite close to the edge
only a short distance from the edge to the middle so things diffuse quickly

Question 11

what is osmosis?

Answer 11

net movement of water molecules from an area of high water concentration to an area of low water concentration
through a partially-premeable membrane

Question 12

what is an isotonic solution?

Answer 12

same water concentration as cell

Question 13

Hypotonic?

Answer 13

higher water conc. – cell swells then bursts ( not for plant cell bc of cell wall)
turgid ( plant)?
lysis ( animal)

Question 14

Hypertonic

Answer 14

low water concentration- water leaves cell, shrinks ( flacid)

plasmolysis- plants
crenation- animals

Question 15

what is active transport

Answer 15

movement of particles against concentration gradient ( from an area of low concentration to an area of high concentration)

Question 16

what does active transport use up?

Answer 16

energy released during respiration

Question 17

who uses active transport?

Answer 17

plans- to absorb minerals in the soil
animals- villi in small intestine to absorb useful nutrients