Cell Biology - Cell Membrane and Transport

Question 1

cell membrane

regarding its permeability

Answer 1

• the cell membrane is said to be selectively permeable as it will allow small soluble molecules to pass through but larger insoluble molecules cannot pass through
• its made of phospholipids and proteins

Question 2

diffusion

Answer 2

diffusion is the movement of molecules down a concentration gradient from a region of high concentration to a region of low concentration until concentrations are equal

Question 3

osmosis

Answer 3

osmosis is the movement of water molecules, down the concentration gradient, from a region of higher water concentration to a region of low water concentration through a selectively permeable membrane

Question 4

plant cell placed in 100% water

effect of osmosis

Answer 4

the cell gains water and is turgid

Question 5

plant cell placed in 5% salt solution

effect of osmosis

Answer 5

no net movement of water so stays the same

Question 6

plant cell placed in 20% salt solution

effect of osmosis

Answer 6

the cell loses water and becomes plasmolysed

Question 7

animal cell placed in 100% water

effect of osmosis

Answer 7

the cell bursts due to water gain

Question 8

animal cell placed in 5% salt solution

effect of osmosis

Answer 8

cell stays the same as there is no net loss

Question 9

animal cell placed in 20% salt solution

effect of osmosis

Answer 9

cell shrinks due to water loss

Question 10

active transport

Answer 10

active is the transport is the movment of molecules and/or ions by membrane proteins from a region of low concentration to a region of high concentration. as this movement goes against the concentration gradient it requires energy in the form of ATP

Question 11

two differences between active and passive transport

Answer 11

active requires energy and goes against the concentration gradient
passive is the opposite

Question 12

phospholipids

Answer 12

type of molecules, many of which make up a double layer in the cell membrane