Diffusion, Osmosis & Active Transport (CIE IGCSE Biology: Co-ordinated Sciences (Double Award))

Which of the following statements would be correct for both diffusion and osmosis?

	does not require energy from the cell	molecules must be separated by a partially permeable membrane	molecules move from a dilute to a more concentrated solution
A	✔	✔	X
B	X	X	✔
C	✔	X	X
D	✔	X	✔

Extended Tier Only

A number of red blood cells were immersed in a pure solution of water before being observed under a microscope. 

There was a dramatic change in their appearance. 

Which row of the table below correctly describes and explains what happened to the red blood cells?

	direction of water movement	from higher to lower concentration	from higher to lower water potential	effect
A	in	✔	X	cells burst
B	in	X	✔	cells burst
C	out	✔	X	cells shrink
D	out	✔	✔	cells shrink

Extended Tier Only

A plant absorbs a number of substances into its roots.

Which row of the table below correctly shows the substances absorbed by the roots and how these substances are absorbed?

	minerals	oxygen	water
A	active transport	diffusion	osmosis
B	active transport	not absorbed	transpiration
C	diffusion	diffusion	osmosis
D	active transport	not absorbed	osmosis

Extended Tier Only

The image below shows two solutions separated by a partially permeable membrane.

Which of the statements below would be true in relation to the image?

A group of students carried out an investigation into osmosis using cylinders of potato.

The results from their experiment are shown below. 

concentration of salt solution / mol dm-3	mass of potato cylinder at start / g	mass of potato cylinder after 24 hours / g
0.2	2.5	2.7

Which statement below correctly explains this change in mass?

	movement of water	cause of this movement
A	out of the potato cells	the salt solution has a lower water potential than the potato cells.
B	out of the potato cells	the salt solution has a higher water potential than the potato cells.
C	into the potato cells	the salt solution has a lower water potential than the potato cells.
D	into the potato cells	the salt solution has a higher water potential than the potato cells.

The image below shows part of a cross-section through a leaf.

Which row of the table below correctly shows the movement of various substances?

	evaporation of water	movement of water by osmosis	diffusion of water vapour
A	3	1	2
B	2	3	1
C	3	2	1
D	2	1	3

Two identical square pieces of beetroot are cut. Each square of beetroot has a mass of 3.0 g. One (S) is placed in a concentrated salt solution, the other (T) is placed in pure water.

What would the masses of the two pieces of beetroot be after 3 hours?

	mass of beetroot squares
	S	T
A	3.0	3.2
B	2.7	3.0
C	2.9	3.2
D	3.1	2.9

A group of students carried out an investigation into osmosis using cylinders of potato. 

The results from their experiment are shown below. 

concentration of salt solution / mol dm-3	length of potato cylinder at start / mm	length of potato cylinder after 24 hours / mm
?	35	33

Which statement below correctly explains this change in length and shows the concentration of the sugar solution?

	concentration of sugar solution	cause of this movement
A	0.0	the sugar solution is more concentrated than the solution inside the potato.
B	0.6	the solution in the potato is more dilute than the solution around the potato.
C	0.6	the solution in the potato is less dilute than the solution around the potato.
D	0.0	the sugar solution is less concentrated than the solution inside the potato.

Extended Tier Only

The image below shows molecules in two solutions separated by a membrane. 

In which direction would there be movement?

	water molecules	solute molecules
A	right to left	no net movement
B	left to right	right to left
C	left to right	no net movement
D	right to left	left to right