IGCSE Biology Transport in plants topical questions

Complete the table comparing the two transport tissues.

1. (a)Complete the substances carried by each tissue.[2]
2. (b)Complete the direction of flow for each tissue.[2]

A leafy shoot is stood in water containing a coloured stain. After 30 minutes the leaf veins are stained.

1. (a)Name the tissue that has taken up the stain.[1]
2. (b)Name the process that draws the stain up the stem.[1]
3. (c)State the term for the loss of water vapour from the leaves.[1]
4. (d)State through which structures most water vapour leaves the leaf.[1]

Explain why root hair cells increase water uptake.

1. (a)Name the process by which water enters a root hair cell.[1]
2. (b)Explain how the shape of a root hair cell helps uptake.[2]

Put the parts of a plant in the order a water molecule passes through them, then answer the questions.

1. (a)Write the letters in the order the water passes through them, starting in the soil.[2]
2. (b)Name the process by which water enters the root hair cell.[1]
3. (c)Name the tissue the water travels in from the root to the leaf.[1]
4. (d)Name the process by which the water leaves the plant at T.[1]

A potometer is used to compare water uptake by a shoot in still air and in moving air from a fan. The shoot takes up 6 cm³ in still air and 18 cm³ in the same time in moving air.

1. (a)Calculate the percentage increase in water uptake in moving air.[2]
2. (b)Explain why moving air increases the rate.[2]
3. (c)State one assumption made when using water uptake as a measure of transpiration.[2]

Describe and explain the effect on transpiration rate of increasing (a) temperature, (b) humidity, and (c) wind speed.

1. (a)Temperature.[2]
2. (b)Humidity.[2]
3. (c)Wind speed.[2]

Explain how the structure of xylem vessels suits them for transporting water.

1. (a)State two structural features of mature xylem vessels.[2]
2. (b)Explain how one feature aids transport and one aids support.[2]

A potometer shoot is exposed to four wind speeds. The distance the bubble moves in 10 minutes is recorded.

1. (a)Calculate the rate of water uptake at 2.0 m/s, in mm per minute.[2]
2. (b)Describe the trend in the data.[1]
3. (c)Explain why moving air increases the rate of water uptake.[2]
4. (d)The rise from 1.0 to 2.0 m/s (8 mm) is smaller than the rise from 0 to 0.5 m/s (12 mm). Suggest why.[1]

A potted plant on a windowsill is weighed at 9 am and again six hours later in bright sunlight; it has lost 150 g. The next night it loses 30 g over the same six hours.

1. (a)Calculate the daytime rate of water loss, in g per hour.[2]
2. (b)Calculate the night-time rate of water loss, in g per hour.[1]
3. (c)Explain the difference between the two rates.[2]
4. (d)State the main route by which the water leaves the plant.[1]

Root hair cells absorb water and mineral ions from dilute soil solution.

1. (a)Explain how root hair cells are adapted for absorption.[2]
2. (b)Name the process by which water enters a root hair cell.[1]
3. (c)Mineral ions are often at a higher concentration inside the root than in the soil. Name the process that takes them up and explain how you know it must be active.[2]
4. (d)State what provides the energy for this uptake.[1]

Explain how the transpiration pull raises water to the top of a tall tree. (Supplement)

1. (a)Describe what happens to water in the leaf that starts the pull.[2]
2. (b)Explain how this moves the whole water column.[2]
3. (c)State what replaces the water at the roots.[1]

A strawberry plant is left in bright sunshine without water for two days. Its leaves droop (wilt). After watering in the evening, the leaves recover by morning. (Supplement)

1. (a)Explain why the leaves wilted in terms of water loss and turgor.[3]
2. (b)Explain how wilting can protect the plant.[2]
3. (c)Explain one disadvantage of wilting for photosynthesis.[1]
4. (d)The strawberry plant’s fruits were ripening during the dry spell. State whether each fruit is a source or a sink, with a reason.[1]

During a growing season, the direction of sucrose flow in a strawberry plant changes. The table shows the plant’s organs at three times. (Supplement)

1. (a)For each time, state which organs are sinks and which are sources.[2]
2. (b)Explain why a root can be a sink in one season and a source in another.[2]
3. (c)Name the carbohydrate transported in the phloem.[1]
4. (d)State in which direction phloem sap can flow.[1]

Four identical leafy shoots are placed in potometers under different conditions. Water uptake in 10 minutes is recorded. (Supplement)

1. (a)Identify the pair of shoots that shows the effect of wind alone.[1]
2. (b)Explain the difference between shoots A and B.[2]
3. (c)Identify the pair of shoots that shows the effect of humidity alone.[1]
4. (d)Explain why humidity lowers the rate of water loss.[2]
5. (e)State why the warm shoots lose water faster than shoot C.[1]