All topics › AQA GCSE Biology › Plant organ system2.3.2 Plant organ systemAQA GCSE Biology (8461), Higher tier · Organisation › Plant tissues, organs and systems
Practise Plant organ system. 14 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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Name the tissue that transports water and mineral ions from the roots to the leaves. xylem
Water evaporates from the leaves of plants and diffuses out through the stomata. Name the cells that open and close the stomata.guard cells Sample questions Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1 Easy 4 marks
The roots, stem and leaves of a plant form an organ system for transporting substances.
(a) Name the tissue that transports water and mineral ions from the roots to the leaves.[1]
(b) Name the tissue that transports dissolved sugars around the plant.[1]
(c) What is the movement of dissolved food molecules through the phloem called?one box.[1]
Diffusion Osmosis Translocation Transpiration (d) What is meant by transpiration ?[1]
Show the answer and mark scheme (c) Answer: Translocation
(d) the loss of water (vapour) from the leaves (by evaporation through the stomata) Question 2 Medium 6 marks
The rate of transpiration is affected by environmental conditions.
(a) Explain why the rate of transpiration increases on a windy day.[2]
(b) Explain why the rate of transpiration decreases when the air is humid.[2]
(c) Explain why the rate of transpiration is higher in bright light than in the dark.[2]
Show the answer and mark scheme (a) moving air removes water vapour from around the leaf so the concentration gradient is kept steep and water vapour diffuses out faster (b) there is more water vapour in the air around the leaf so the concentration gradient is smaller and water vapour diffuses out more slowly (c) more stomata are open / stomata open wider in the light (for photosynthesis) so more water vapour can diffuse out of the leaf Question 3 Hard 7 marks
A student wanted to investigate the effect of light intensity on the rate of transpiration of a leafy shoot using a potometer.
(a) Plan an investigation the student could carry out.[6]
(b) Give the reason why the student should use the same leafy shoot throughout the investigation.[1]
Show the answer and mark scheme (a) cut the shoot under water and fit it into the potometer under water; make the joints airtight (e.g. with petroleum jelly); dry the leaves introduce an air bubble into the capillary tube vary light intensity by placing a lamp at different distances from the shoot, e.g. 10, 20, 30, 40 cm (or use a light meter) use a heat shield / tank of water between the lamp and the shoot to keep the temperature constant allow the shoot to adjust for a few minutes at each light intensity measure the distance the bubble moves in a set time, e.g. 5 minutes, and reset the bubble with the reservoir keep other variables the same: same shoot, same temperature, humidity and air movement (no draughts) repeat at each light intensity and calculate the mean rate (distance or volume per minute) Marked with levels of response: the full level descriptors are in the app.
(b) different shoots have different numbers / areas of leaves / numbers of stomata Related subtopics
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