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Describe Transpiration

In this worksheet, students will describe transpiration.

'Describe Transpiration' worksheet

Key stage:  KS 4

GCSE Subjects:   Biology: Single Subject, Biology: Combined Science

GCSE Boards:   Pearson Edexcel

Curriculum topic:   Plant Structures and Their Functions

Curriculum subtopic:   Plant Structures and Their Functions

Difficulty level:  

Worksheet Overview

QUESTION 1 of 10

Did you know that plants only use about 5-6% of all the water they absorb for photosynthesis? So what happens to all that water anyway?  Let's find out more below.

 

Image of photosynthesis

 

Plants can’t help but lose water continually to the air. This is called transpiration. 

Water is constantly lost from the leaves of a plant through pores called stomata. When a plant opens its stomata to allow carbon dioxide in for photosynthesis, water will evaporate and diffuse out of the stomata. More water is drawn up from the stem and the roots to replace the lost water. As water moves from the roots to the leaves, more water is drawn up from the soil into the root hair cells. This process is known as the transpiration stream.

Although transpiration is inevitable, it's also quite useful! It helps the plant remain cool and allows minerals to be drawn up the plant along with the water.

 

Factors affecting transpiration

 

Transpiration is affected by many factors:

1)  Temperature - increasing the temperature makes transpiration happen faster, the plant loses more water from its leaves.
2)  Humidity - if it's really humid it means there's a lot of moisture in the air, the plant doesn't transpire as much so doesn't lose as much water.
3)  Wind - if it's really windy water vapour is blown away from the leaf. This causes the leaf to transpire faster so the plant loses more water from its leaves.
4)  Light intensity - if its really sunny, the stomata will open to let in more carbon dioxide for photosynthesis, this causes the plant to lose water.

 

Plant adaptations

Plants have adaptations that allow it to do a particular job.

Image of root hair cell

 

Root hair cells are specialised cells found at the roots of a plant (see image above). These cells are thin and long making them useful to manoeuvre between soil particles in search of water. The large surface area of the root hair cell allows a greater chance of contact with water and minerals.​ 

 

Image of leaf anatomy

 

Another adaptation of the plant is found in the leaf of a plant​. The lower epidermis layer contains the stomata (stoma for one pore). These stomata allow gases in and out of the underside of the leaf. The stomata are found between guard cells which open or close the stomata. The stomata will open to allow in carbon dioxide for photosynthesis during the day but will close during the night when there's no sunlight. 

 

 Image of xylem and phloem vessels

 

Water moves through xylem vessels.  Xylem vessels are a hollow continuous tube that transports water in one direction and minerals from a plants roots to the plant's leaves via the stem.

Another vessel the plant has is called the phloem. The phloem vessels move food substances that the plant has made by photosynthesis to where they are needed (for example in growing parts of the plant and storage). Food travels up and down the stem. This is known as translocation. Phloem vessels are made up of living cells and have no nuclei, allowing food substances to take up maximum space.


In the following activity, you will describe how transpiration occurs in plants.

 

Image of xylem and phloem vessels

 

The xylem vessel doesn't have end walls between cells. How does this adaptation help the plant? 

 

It allows food to be transported quickly

It allows water to be transported quickly

It allows carbon dioxide to be transported quickly

The image below shows the structure of a leaf.

 

Image of leaf anatomy  

 

What is the name of structure X that water vapour is lost from? Type one answer below. 

Image of root hair cell

 

Root hair cells have an important job to do - they allow water and minerals to be absorbed from the soil.

 

What two features of the root hair cell allow water and minerals to be absorbed by the plant?

Thin walls to pass through

Thick walls to pass through

Small surface area to take up less space

Large surface area to absorb more water and ions

Describe transpiration.

 

Thin walls to pass through

Thick walls to pass through

Small surface area to take up less space

Large surface area to absorb more water and ions

Environmental factors can affect the rate of transpiration. 

Give some examples of these factors.

Fertiliser

Temperature

Wind

Farming

What does the term translocation mean?

 

The movement of nutrients made through photosynthesis to where it's needed

The movement of water through the plant

The movement of gases in and out of the stomata

During photosynthesis, glucose and oxygen are made. Glucose is a form of sugar and needed around the plant for many different processes.

 

What is the name of the cell that transports sugar around the plant?

Which of the following environmental factors would increase the rate of transpiration in a plant?

A very sunny day

A very cold day

A very hot day

A very humid day

Fill in the blanks below explaining why transpiration is normally slower at night than during the day.

 

This is because the ...A... are closed during the ...B... as plants can't ...C..., so plants won't lose ...D...

Column A

Column B

A
water
B
photosynthesise
C
stomata
D
night

State one difference between the xylem and phloem vessel.

The xylem transports substances in one direction only

The xylem transports sucrose around the plant

The phloem transports substances up and down the plant

The phloem transports water up and down the plant

  • Question 1

Image of xylem and phloem vessels

 

The xylem vessel doesn't have end walls between cells. How does this adaptation help the plant? 

 

CORRECT ANSWER
It allows water to be transported quickly
EDDIE SAYS
As the xylem forms one continuous tube, water can flow directly to the leaves where it's used for photosynthesis.
  • Question 2

The image below shows the structure of a leaf.

 

Image of leaf anatomy  

 

What is the name of structure X that water vapour is lost from? Type one answer below. 

CORRECT ANSWER
Stomata
Stoma
EDDIE SAYS
The stomata are pores that allow gas exchange to occur, they are normally surrounded by cells called guard cells that open and close, controlling which gases enter or exit the leaf.
  • Question 3

Image of root hair cell

 

Root hair cells have an important job to do - they allow water and minerals to be absorbed from the soil.

 

What two features of the root hair cell allow water and minerals to be absorbed by the plant?

CORRECT ANSWER
Thin walls to pass through
Large surface area to absorb more water and ions
EDDIE SAYS
Root hair cells have thin walls which allow water and mineral ions to pass through really easily and quickly. The tiny projections of the root hair cell increase the surface area, allowing more water to be in contact with the cell. This means more water and minerals, which are needed for the process of photosynthesis, can pass into the root hair cell.
  • Question 4

Describe transpiration.

 

CORRECT ANSWER
EDDIE SAYS
Don't forget, transpiration is all to do with water loss. Some plants are great at reducing water loss, like cacti that live in the desert.
  • Question 5

Environmental factors can affect the rate of transpiration. 

Give some examples of these factors.

CORRECT ANSWER
Temperature
Wind
EDDIE SAYS
Humidity and light intensity are other factors that can affect the rate of transpiration.
  • Question 6

What does the term translocation mean?

 

CORRECT ANSWER
The movement of nutrients made through photosynthesis to where it's needed
EDDIE SAYS
Translocation is the movement of mainly sugars and amino acids around the plant.
  • Question 7

During photosynthesis, glucose and oxygen are made. Glucose is a form of sugar and needed around the plant for many different processes.

 

What is the name of the cell that transports sugar around the plant?

CORRECT ANSWER
Phloem
Phloem's
Phloem cell
Phloem tissue
EDDIE SAYS
Don't worry if you found that tricky! Phloem cells transport sugars up and down the stem (this is called translocation). The glucose is needed for respiration, growth and storage.
  • Question 8

Which of the following environmental factors would increase the rate of transpiration in a plant?

CORRECT ANSWER
A very sunny day
A very hot day
EDDIE SAYS
A very sunny day is great for photosynthesis! The stomata will open allowing more carbon dioxide in but this will also allow water to escape. The high temperature will mean the water evaporates quickly, increasing the transpiration rate.
  • Question 9

Fill in the blanks below explaining why transpiration is normally slower at night than during the day.

 

This is because the ...A... are closed during the ...B... as plants can't ...C..., so plants won't lose ...D...

CORRECT ANSWER

Column A

Column B

A
stomata
B
night
C
photosynthesise
D
water
EDDIE SAYS
The plant's stomata don't need to open at night as there's no sunlight to power photosynthesis. This allows plants to reduce water loss via transpiration.
  • Question 10

State one difference between the xylem and phloem vessel.

CORRECT ANSWER
The xylem transports substances in one direction only
The phloem transports substances up and down the plant
EDDIE SAYS
Try to remember xylem and phloem vessels are almost opposites! The xylem is to do with transporting water and the phloem is to do with nutrients.
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