Plants

Question 1

Describe a method you could use to find the surface area of a leaf

Answer 1

Draw around leaf on graph paper;

Both aspects needed for mark − drawing and type of paper.

2. Count squares (however described);

There is no reward for additional detail e.g. dealing with part squares.

3. Multiply by 2 (for upper and lower leaf surface);

Question 2

Explain how one of the other labelled parts reduces water loss plants

Answer 2

reference to hairs / position of stomata (sunken stomata /
stomata in pits )
LINKED to reduced air movement / trap layer of air /
trap water vapour (reject water) / maintains humidity;

reduces diffusion gradient / concentration gradient of water /
water potential gradient;

OR

stoma can close;
reduces area for evaporation or transpiration;

Question 4

The body of a flatworm is adapted for efficient gas exchange between the water and the cells inside the body.
Using the diagram, explain how two features of the flatworm’s body allow efficient gas exchange.

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

______________________________________________________________

(2)

(b) (i) A leaf is an organ. What is an organ?

______________________________________________________________

______________________________________________________________

______________________________________________________________

(1)

(ii) Describe how carbon dioxide in the air outside a leaf reaches mesophyll cells inside the leaf.

Answer 4

Thin / flat body) so short distance for diffusion / short diffusion pathway;

Ignore references to membrane, wall, body surface

2. (Thin / flat body so) large surface area to volume ratio;

‘It’ refers to flatworm’s body

2

(b) (i) A group of tissues;

Ignore references to function Group = more than one

1

(ii) 1. (Carbon dioxide enters) via stomata;

Reject stroma

2. (Stomata opened by) guard cells;
3. Diffuses through air spaces;

Allow concentration gradient. Reject along gradient unless direction made clear

4. Down diffusion gradient;

Question 5

LEARN HOW TO DO MEAN DENISITY OF STOMAtA