Getting in and out of cells

Question 1

How do dissolved substances move in and out of cells?

Answer 1

diffusion and active transport

Question 2

How does water move in and out of cells?

Answer 2

osmosis

Question 3

diffusion

Answer 3

molecules move from a high concentration to a lower concentration until the concentrations are equal

the net movement is down the concentration gradient

some molecules will move against it

Question 4

active transport

Answer 4

energy from respiration is used to move molecules from a low concentration/dilute solution to a high/concentrated solution

across a partially permeable membrane

there is net movement against the concentration gradient

Question 5

osmosis

Answer 5

net movement of water molecules across a partially permeable membrane froma low to a high concentration

Question 6

A 30% sucrose solution was places inside a partially permeable membrane in a beaker of water. There is more solution inside the membrane than water in the beaker

At the start, the level of solution inside the tube and the level of water in the beaker were the saem.

Name the process that caused the change and explain what happened [3]

Answer 6

the process is called osmosis

to start with there were more water molecules in the water than in the same volume of sucrose solution, so more water molecules crossed the membrane into the tubing than the other way

so the level of solution inside the membrane rose

Question 7

Define osmosis [2]

Answer 7

the net movement of water molecules from a region of higher water concentration to a region of lower water concentration across a partially permeable membrane

Question 8

a) Give one similarity between diffusion and osmosis [1]

b) Give one difference between diffusion and active transport [1]

Answer 8

a) neither diffusion nor osmosis need energy
b) diffusion does not need energy but active transport does, diffusion takes place down a concentration gradient, active transport takes place against a concentration gradient

Question 9

A plant root is treated with a poison that prevents respiration.

Explain whether the root cells will still be able to absorb water and mineral ions from a dilute solution. [4]

Answer 9

the cells will still be able to absorb water by osmosis because it is a passive process

the cells will not be able to absorb mineral ions; mineral ions are absorbed by active transport and that needs energy from respiration