Uptake and transport of water and ions

A plant was put into water that contained black dye. After 24 hours, the plant was taken out and slices were cut from the root and the stem. Which diagram shows the results?

May/June 2015

Water and ions can move to the xylem of a plant root along the cell walls, without crossing a cell membrane. By what process do these substances pass through the cell walls?

May/June 2017

A cut shoot from a plant is put into a beaker of blue dye solution for one hour, as illustrated. The stem of the shoot is then sliced at X and viewed with a microscope. In which part of the stem is the blue dye concentrated most strongly?

May/June 2017

When plants grow in soil that is saturated with water, their roots do not receive enough oxygen. How will the functions of root hairs be affected under these conditions?

May/June 2018

A plant was put into water that contained black dye. After $24$ hours, the plant was taken out and cross-sections were cut from the root and the stem. Which diagram represents the results?

May/June 2019

The diagram shows several cells in the root of a plant taking up water from the soil. In what way does the water potential of cell 2 differ from the water potentials of cells 1 and 3?

May/June 2019

A plant was kept in water mixed with black dye. After $24$ hours, the plant was removed and sections were cut from the root and the stem. Which diagram shows the results?

May/June 2019

The diagram depicts a root hair cell from a lemon tree together with some soil particles.

May/June 2021

The rate at which a root hair cell absorbed nitrate ions was measured at a range of soil nitrate concentrations. At $X$, the nitrate concentration in the soil is equal to that inside the cell. Which graph shows how the rate of absorption changes as the nitrate concentration in the soil changes?

May/June 2022

Xylem vessels are cells adapted for conduction and support. Which two adaptations enable them to carry out these functions?

May/June 2022

The rate at which a root hair cell absorbs nitrate ions was determined at a range of nitrate concentrations in the soil. At $X$, the nitrate concentration in the soil matches the concentration inside the cell. Which graph illustrates how the absorption rate changes with the nitrate concentration in the soil?

May/June 2022

Root hairs absorb water and ions from the soil. Which table indicates the correct concentrations of water and ions in the root hair?

May/June 2023

The diagram shows the concentration of magnesium ions in a root hair cell of a healthy plant and in the soil water around the root hair cell. The plant is constantly using magnesium ions. To keep the plant healthy, in which direction will the magnesium ions move?

May/June 2024

Which route is followed by water and mineral ions through a plant?

May/June 2024

Water passes from the soil into the atmosphere via a plant. The water enters the plant through the root hair cells and then moves into the root cortex. From the root cortex, where does the water move into?

May/June 2024

By what process do plants take up nitrate ions using active transport?

Oct/Nov 2015

Explain how wilting develops in a plant.

Oct/Nov 2015

The uptake rate of nitrate ions by a root hair cell was recorded at several different nitrate concentrations in the soil. At $X$, the nitrate concentration in the soil is equal to that inside the cell. Which graph shows how the absorption rate changes as the nitrate concentration in the soil increases?

Oct/Nov 2016

Part C

Oct/Nov 2017

Why is the large surface area of a plant’s root hairs important?

Oct/Nov 2019

Hydroponics is a method for raising plants without soil. The diagram shows plants being grown by hydroponics.

Oct/Nov 2020

Water enters living organisms and is moved to all of their cells. Compare how water is transported in a human and in a flowering plant.

Oct/Nov 2021

What roles are carried out by xylem vessels?

Oct/Nov 2022

Which row identifies the processes by which nitrate ions and water from soil enter a root hair cell?

Oct/Nov 2023

A leafy stem was cut from a plant and then put into a red dye solution for 18 hours. The diagram illustrates a transverse section of the stem after 18 hours. Which tissue will appear red?

Oct/Nov 2024

Root hair cells absorb water and ions from the soil. Which row correctly shows the way that water and ions enter root hair cells?

Oct/Nov 2024

The diagrams illustrate transverse sections of a dicotyledonous root, stem and leaf. The vascular tissues are marked with the numbers 1-6. The cut ends of root pieces, stem pieces and leaf stalks are put into water that contains a red dye. After several hours, the coloured water has moved through some of the vascular tissues. Which vascular tissues are shown in red?

Oct/Nov 2025