⚡ Show all reasoning — the AI marks against the AQA mark scheme. Partial credit for correct biology even if wording differs.
1 markXylem vs phloemAQA 8461 style
Which of the following correctly describes the function of phloem?
A Transports water and minerals from roots to leaves, upward only
B Transports dissolved sugars from leaves to all other parts of the plant, in both directions
C Provides structural support to the stem through lignified walls
D Transports water only, not minerals
3 marksTranspiration factorsAQA 8461 P1 style
A student measures transpiration rate using a potometer on a warm, windy day, then again on a cool, still day. The rate is higher on the warm windy day. Explain why. (3 marks)
Hint: Explain two factors: temperature (kinetic energy/evaporation rate) and wind (concentration gradient). Link each to the rate of water loss.
+30 XP
1 markGuard cellsAQA 8461 style
What causes stomata to open in the light?
A Guard cells produce glucose by photosynthesis which is converted to starch, making them rigid
B Guard cells absorb water by osmosis, become turgid and their shape changes to open the pore
C Guard cells lose water and become flaccid, pulling apart to open the pore
D Guard cells die in the light, leaving a gap
4 marksXylem structure and functionAQA 8461 style
Describe the structure of xylem vessels and explain how this structure is suited to their function. (4 marks)
Hint: Structure: dead cells, hollow, lignified walls, end walls removed. Function: link each structural feature to how it helps transport water.
+40 XP
1 markTranspiration directionAQA 8461 style
In which direction does translocation in phloem move?