The smart way to improve grades

Comprehensive & curriculum aligned

Try an activity or get started for free

Analyse the Roles of Xylem and Phloem in Plants

In this worksheet, students will analyse the structures and roles of xylem, phloem and specialised transport cells.

'Analyse the Roles of Xylem and Phloem in Plants' worksheet

Key stage:  KS 4

GCSE Subjects:   Component 1: Concepts in Biology: Single Subject, Component 1: Concepts in Biology: Combined Science

GCSE Boards:   Eduqas

Curriculum topic:   Transport Systems

Curriculum subtopic:   Transport Systems in Plants

Difficulty level:  

Worksheet Overview

QUESTION 1 of 10

In the same way as humans have arteries and veins to carry blood, plants have their own ways of transporting substances so that they can survive.

 

Plants have two main transport systems: xylem and phloem.

And between them there are four types of specialised cells we need to know: the vessels of the xylem, sieve tubes and companion cells of the phloem, and root hair cells in the roots.

 

A pot plant

 

Xylem:

 Water and minerals are transported by xylem.

They are hollow tubes with continuous walls that are made from specialised dead cells called vessels.

 

Looking at the xylem in the picture below, these cells are now empty and have no end walls (no ceilings or floors) so they can be joined together smoothly, reducing the water turbulence.

The walls are also strengthened and supported by a chemical called lignin.

 

This secure structure allows the transport of water and minerals upwards from the roots and through the stem to the rest of the plants in transpiration - so think root to leaves!

Surprisingly, this antigravity direction is what we call a physical process, meaning the xylem doesn’t need energy to push its water contents around.

 

Xylem and phloem

 

Phloem:

Phloem transports sugars (from photosynthesis) and amino acids around the plant in a dissolved form.

Because photosynthesis occurs anywhere chloroplasts are, the dissolved sugar and amino acids are transported upwards and downwards to where the plant needs them for growth, energy storage as starch (e.g. in bulbs), making seeds and respiration. 

Phloem has its own term for this transport called translocation.

 

The phloem is actually a combination of two cell types, both of which are alive, depend on each other and are well adapted for their roles (see the diagram above):

Sieve tube cells have no nuclei and are stacked on top of each other, making the tunnels of the phloem. The cytoplasm of the neighbouring cells interacts through the gaps in the ends of each cell.

Translocation needs energy, which companion cells provide, so every sieve tube gets at least one companion cell so that it can function!

 

Xylem and phloem in a root and a stem

 

When thinking about the plant as a whole, xylem and phloem are arranged differently depending on whether we’re looking at the roots or the stem.

In the roots, xylem offer the most support by being the central portion, with the phloem around the perimeter.

In the stem though, xylem and phloem are arranged in pairs called vascular bundles (imagine an artery and a vein side by side).

 

A root hair cell 

 

Root Hair Cells:

These allow a plant to absorb water from the soil using osmosis.

They are specially adapted to be long and thin so that they can get between pieces of soil and they have a larger surface area for water absorption.

 

The gradient here is dependent on there being less water in the root hair cytoplasm than in the soil, and so as water comes in, the cell also actively transports mineral salts from their low concentration in the soil to an already high concentration in the cytoplasm, maintaining the influx of water. 

And as active transport always needs energy, these cells respire a lot to produce the energy the cell needs to function.

 

Are you ready to have a go at some questions now?

Identify which substance is transported by which transport system:

Column A

Column B

Phloem
Water (absorbed)
Xylem
Water and minerals
Root hair cells
Sugar and amino acids

Which of these structures require energy for them to be able to perform their function?

Xylem

Phloem

Root hair cells

In the phloem, the transport of sugars and amino acids occurs in which direction?

Only upwards

Upwards and downwards

Only downwards

How is the structure of the xylem adapted for its function?

Only upwards

Upwards and downwards

Only downwards

Which transport system does each of the cells below belong to?

Only upwards

Upwards and downwards

Only downwards

How are xylem and phloem arranged in plants? 

Only upwards

Upwards and downwards

Only downwards

What chemical reinforces xylem?

Which specialised plant structure uses which method of transport?

Column A

Column B

Translocation
Xylem
Physical Process
Root hair cells
Osmosis and active transport
Phloem

Root hair cells use osmosis and active transport to absorb water from the soil into the roots.

 

Match the substance concentrations with their correct locations.

How does being long and thin help the root hair cells to perform their function?

They can reach water in between soil particles

They don't disrupt other root hair cells

This increases their surface area

More cells can be packed together

  • Question 1

Identify which substance is transported by which transport system:

CORRECT ANSWER

Column A

Column B

Phloem
Sugar and amino acids
Xylem
Water and minerals
Root hair cells
Water (absorbed)
EDDIE SAYS
Did you feel confident answering this first question? Plants organise their transport systems based on what they're carrying: Xylem transports water and minerals through the stem. Phloem is in charge of moving sugars and amino acids that have been dissolved in water. Root hair cells are responsible for water absorption. Make sure you're really confident with these definitions before moving on!
  • Question 2

Which of these structures require energy for them to be able to perform their function?

CORRECT ANSWER
Phloem
Root hair cells
EDDIE SAYS
So, let's go over this question by combining these answers with what we learnt from the previous question! The xylem undergoes a physical process, which means it doesn't use energy to perform its function - meaning that it's passive. However, the phloem's translocation does need energy to work - think about the purpose of the companion cells! The root hair cells are interesting because really the answer is yes and no! The process of osmosis, drawing the water into the cell from the soil, is by simple diffusion, so this part doesn't use energy. But the answer is yes because osmosis can only be maintained as long as the water concentration in the cytoplasm stays lower than that in the soil, and to do this, the cell has to use active transport to force in minerals, which is very energy-dependent.
  • Question 3

In the phloem, the transport of sugars and amino acids occurs in which direction?

CORRECT ANSWER
Upwards and downwards
EDDIE SAYS
It's very important to get this sorted out in your mind, so that you can recognise one of the key differences between xylem and phloem. Phloem transports substances up and down! While xylem only moves water and minerals upwards.
  • Question 4

How is the structure of the xylem adapted for its function?

CORRECT ANSWER
EDDIE SAYS
Did you get all the blanks correct? Xylem has some special adaptations that helps it fulfill its function. It's a hollow tube made from dead cells which are now empty, and the bottoms of the cells have also been removed, so all their cytoplasm melds together into one steady stream. This continuous shape, with no end walls, means there is less turbulence in the water flow, making transport easier.
  • Question 5

Which transport system does each of the cells below belong to?

CORRECT ANSWER
EDDIE SAYS
The questions are getting harder now but you need to be familiar with these terms. The xylem's specialised cells are known as vessels. The phloem has two types of cells that work together to carry out the phloem's function. The living sieve tubes have no nuclei and have gaps in their end walls to help substances flow easily. This requires energy, which is what the companion cells supply. (Tip: think of a companion cell as a buddy cell that the sieve tubes rely on!)
  • Question 6

How are xylem and phloem arranged in plants? 

CORRECT ANSWER
EDDIE SAYS
Were you stumped by that final blank? It was a tricky word to remember - and to spell! In the root, xylem is the central structure that gives the main support, while the phloem wraps around it. But when you move up the stem, if you broke it in half and put it under a microscope, you would see that the xylem and phloem are actually arranged in pairs in a circle formation, which we call vascular bundles.
  • Question 7

What chemical reinforces xylem?

CORRECT ANSWER
lignin
EDDIE SAYS
Think back to what you have learned about the structure of xylem. You might recall that they are continuous hollow tubes that have no end walls. This might suggest a rather fragile tissue, particularly since it is made up of dead cells. This means that they need to be strengthened by a substance called lignin, which adds structure and support to the dead cell walls.
  • Question 8

Which specialised plant structure uses which method of transport?

CORRECT ANSWER

Column A

Column B

Translocation
Phloem
Physical Process
Xylem
Osmosis and active transport
Root hair cells
EDDIE SAYS
There was lots going on in this question - how did you get on? The phloem works using translocation, while the xylem's method of transport is referred to as a physical process (more details on these in the next question!) The root hair cell, however, has two processes happening at the same time - the movement of water from the soil into its cytoplasm through osmosis, and then the active transport of salts into the root hair cell cytoplasm to keep the gradient needed for continuous water absorption.
  • Question 9

Root hair cells use osmosis and active transport to absorb water from the soil into the roots.

 

Match the substance concentrations with their correct locations.

CORRECT ANSWER
EDDIE SAYS
So, this final question is really testing your grasp of what osmosis and active transport mean and how they apply in the context of root hair cells. For osmosis to bring water into the cytoplasm, there has to be more water in the soil than in the cell for the gradient to favour moving water in that direction. To maintain the process of osmosis and keep supplying the plant with water, it is necessary to keep a lower water concentration in the cells than in the soil. To do this, the root hair cells need to absorb more mineral salts from the soil to keep the water concentration levels lower in the cytoplasm. The root hair cells need to use active transport to do this because it is going against the concentration gradient since there is a higher concentration of mineral salts in the root hair cells than in the soil. Phew - that was complicated! Well done for reaching the end of this very challenging activity!
  • Question 10

How does being long and thin help the root hair cells to perform their function?

CORRECT ANSWER
They can reach water in between soil particles
This increases their surface area
EDDIE SAYS
Being long and thin is a really useful adaptation for root hair cells. It helps them to reach the water in between soil particles, and also increases their surface area for greater water absorption.
---- OR ----

Get started for free so you can track and measure your child's progress on this activity.

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started
laptop

Try an activity or get started for free