iheartbio.weebly.comiheartbio.weebly.com/uploads/1/3/4/2/13422000/2enutriti… · Web view2.18 write the word equation and the balanced chemical symbol equation for ... 117 from

Edexcel IG Bio 2e Nutrition in Plants

Nutrition in Plants (2e)Learning outcomes (Students will be assessed on their ability to):

2.17 describe the process of photosynthesis and understand its importance in the conversion of light energy to chemical energy

2.18 write the word equation and the balanced chemical symbol equation for photosynthesis

2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis

2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis

2.21 understand that plants require mineral ions for growth and that magnesium ions are needed for chlorophyll and nitrate ions are needed for amino acids

2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll

N.B. learning outcome "2.67 understand the origin of carbon dioxide and oxygen as waste products of metabolism and their loss from the stomata of a leaf" is taught implicitly as part of this topic.

N.B. The workbook is strucutured in two parts. The first outlines activities that will help you develop notes that can be used later for revision. The second is a set of summary questions designed to help you test your understanding.

1


Note development

2.17 describe the process of photosynthesis and understand its importance in the conversion of light energy to chemical energy

Photosynthesis is the most important metabolic process for the survival of life on this planet. Watch the click4biology video ‘2.17 photosynthesis’ or read p108-112, 117 from Edexcel IGCSE Biology and make some summary notes below then answer the questions.

1. Photosynthesis is about energy transfer. Briefly describe the energy transfer.

2. Give a reason why plants store energy in a starch (a polymer of glucose) rather than just as glucose.

3. Suggest reasons why plants need to make glucose. Why do they create glucose only to break it down to release the energy in the process of respiration? Why don’t plants directly use the energy from the sun?

2


4. Give two reasons why animal life is dependent on plant life

2.18 write the word equation and the balanced chemical symbol equation for photosynthesis

The word equation and balanced symbol equations for photosynthesis:

Light energy(sun)

Carbon Dioxide + Water Glucose + Oxygen(energy contained in chemical bonds)

(by product)

6CO2 + 6H2O C6H12O6 6O2

You need to memorise and be able to use both forms of the equation. Possible strategies are: Produce a poster centering on a plant and annotate it to show the equation and where the

substrates and products enter and leave the plant Breakdown the equation in flash cards and practise building the equations using them

2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis

5. Outline how carbon dioxide affects the rate of photosynthesis: Complete the sketch graph to show how the rate of photosynthesis changes with carbon

dioxide concentration.

Concentration of carbon dioxide

Rate of photosynthes

3


Explain the trend shown on the graph. (hint: in your answer refer to the equation for photosynthesis)

6. Outline how light intensity affects the rate of photosynthesis: Complete the sketch graph to show how the rate of photosynthesis changes with light

intensity.

Explain the trend shown on the graph. (hint: in your answer refer to the equation for photosynthesis)

Light intensity


4


7. Outline how light intensity affects the rate of photosynthesis: Complete the sketch graph to show how the rate of photosynthesis changes with

temperature.

Explain the trend shown on the graph. (hint: in your answer refer to particle theory and enzymes)

8. Extension: suggest, with reasons, how the rate of photosynthesis changes with pH.

Temperature


5


2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis

Diagram of a leaf cross section

Light micrograph of a leaf cross section (x100)

source: http://klemow.wilkes.edu/BIO122-LabQuiz2.html

6

http://klemow.wilkes.edu/BIO122-LabQuiz2.html


9. Complete the table below to indicate: The location of each Part or tissue. The role of each part/tissue in supporting photosynthesis How the part/tissue is adapted for it’s function.

Number Structure Function

Air Spaces

Guard Cells

Upper Epidermis

Lower Epidermis

Chloroplast

Spongy Mesophyll

Waxy cuticle

Stomata

Palisade Mesophyll

Vascular bundle

Xylem

Phloem

10. Identify and label as all the parts and tissues that can be clearly seen on the micrograph.

7


2.21 understand that plants require mineral ions for growth and that magnesium ions are needed for chlorophyll and nitrate ions are needed for amino acids

11. Complete the table to outline the molecules and functions supported by magnesium and nitrogen.

Mineral ionMolecules

requiring the mineral ion

Detail of the functions supported by the mineral ion

and it’s molecules

Symptoms of a plant deficient in the

mineral ion

Nitrogen

Magnesium

12. Describe how mineral ions enter the plant and reach the organs that require them.

13. State the name of the process by which mineral ions enter a plant and outline what is required for this process to occur.

8


2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll

The word equation for photosynthesis:

Light energy(sun)

Carbon Dioxide + Water Glucose + Oxygen(energy contained in chemical bonds)

(by product)

Photosynthesis is usually measured the generation of products: the evolution of oxygen production of starch (starch is a polymer made from glucose)

Evolution of oxygen

You will first develop a method for measuring the evolution of oxygen. It is a basic method and you will both criticise the method and suggest improvements and extensions.

14. Sort the statement below into a useable method:

Order Step

Invert the water plant and keep it submerged by weighing it down (plasticine and paper clips both work well).Measure the (oxygen) bubble production by counting the number of bubbles evolved in two minutesWhilst submerged cut the stem (near to the top), this enables oxygen bubbles to escape.Place an a strong artificial light source, e.g. a desk lamp close to the beaker containing the water weedWait for (at least) 5 minutes as the plant equilibrates with the conditions.Calculate the rate of photosynthesis use the equation below:

Rate of photosynthesis (bubble/min) = bubbles generated (bubbles)Time taken (min)

Place a short piece of a water plant (typically elodea, cambomba or a similar species) in a solution of sodium hydrogen carbonate (this provides a good source of carbon dioxide).

9


15. Describe three improvements to the method above that would make it a fairer test, i.e. address the control variables in more detail.

16. Suggest an addition to the method to make it more reliable.

17. Suggest a more accurate way of measuring oxygen production than counting bubbles.

18. Suggest additions to the method to measure the effect of: Light intensity

Concentration of carbon dioxide

n.b. this is a good opportunity to design and carry out your own lab either using one of the variables above or another suitable variable that affects the rate of photosynthesis in water plants.

10


19. Suggest a simple experiment to check that the gas evolved is indeed oxygen.

Production of starch

20. Follow the method below and then record the results in the table provided.

Method: Placing a plant in the dark for 24 hours to de-

starch the leaves (the starch will be converted to glucose and used for respiration and without light it cannot be replaced by photosynthesis).

Cover part of a leaf using aluminium foil. Place the plant in bright sunshine for 12

hours Remove a leaf from the plant Put the leaf in boiling water for 1 minute (to

destroy the cell membranes so that chlorophyll molecules can pass through)

Heat the leaf in boiling ethanol (to remove/dissolve the green chlorophyll from from leaf)

Place leaf into room temperature water (to rehydrate and soften the leaf so that it can be spread out)

Drop iodine solution onto the leaf (test for starch) – blue-black colour will show the presence of starch.

Results:

Leaf region Colour after iodine test Starch Present?

Uncovered

Covered

Image source: http://www.elateafrica.org/elate/biology/biologyindex.html

11

http://www.elateafrica.org/elate/biology/biologyindex.html


21. The practical provides evidence that a factor is required for photosynthesis. Name the factor.

22. The image to the right shows a variegated leaf. Describe both a method to show variegated leaves could be used to test whether chlorophyll is needed for photosynthesis to occur and the expected results.

23. A solution of potassium hydroxide can be used to extract carbon dioxide from surrounding air. Suggest how the method could be changed to test whether chlorophyll is needed for photosynthesis to occur and outline the expected results. Hint: make sure you include a control in your test.

Image source: http://mol-biol4masters.masters.grkraj.org/

12

http://mol-biol4masters.masters.grkraj.org/

http://mol-biol4masters.masters.grkraj.org/


Summary questions:

1. The diagrams show a clover leaf and one of its cells. Complete the table listing structures of the clover cell. (4)

2. Complete the paragraph describing how tomato leaves make glucose. (6)

The leaves take in __________________________ gas from the air and combine it with __________________________ to

make glucose and __________________________ gas. The process is called __________________________ and will only

work if the leaves contain __________________________ to trap __________________________ energy.

3. Complete the table by writing yes or no in each box. (4)

13

cell structure letter

cell wall

chloroplast

cytoplasm B

nucleus

vacuole


4. Complete the word equation for photosynthesis. (3)

5. The diagram shows two cells from a tomato plant.

a. Label cell B. (2)

b. Which cell is from a leaf and which from a root? Explain the reasons for your choice (3)

14


6. Plants need certain substances to help them make their food by photosynthesis. Draw a straight lines indicate the role of each substance in photosynthesis. One has been done for you. (4)

7. The diagrams show the results of an experiment to find out how light intensity affects the amount of gas produced by a water plant in a day.

a. In which light intensity was most gas produced? (1)

b. Name the gas produced. (1)

c. Name the process which produces the gas. (1)

d. Name three factors, other than light intensity, that could affect the amount of gas produced in this experiment. (3)

15


8. The bar graph shows the number of times a lawn in Britain was cut during one year.

a. How many times was the lawn cut during the year? (1)

b. Explain why it was not necessary to cut the grass in Jan, Feb and Dec. (3)

c. Explain why the grass was cut most often during July and August. (3)

9. The graph shows the results of experiments on the factors that affect the rate of photosynthesis in a tulips grown in a greenhouse. Throughout the experiments the temperature was kept at the optimum for the enzymes in the plant.

a. State which factor is limiting the rate of photosynthesis between points X and Y. Explain your answer. (3)

b. Explain the shape of the graph between points P and Q. (2)

16


c. If the tulip grower wished to increase photosynthesis by installing artificially lighting and increasing the carbon dioxide supply what other factors should he/she consider? (2)

10. A student set up the following experiment to study the effect of different colours of light on the rate of photosynthesis in an underwater plant (Canadian pondweed).

The shoot was given light of a colour and left for 5 minutes before measurements were taken. The time taken for the release of 20 bubbles from the shoot was noted. The results are shown in the bar graph.

a. Calculate the time taken to release 50 bubbles using yellow light? (1)

b. State the name of the gas produced (in the bubbles). (1)

c. Explain why it would not be a good idea to provide the plant with only green light. (2)

11. The graph below shows the effect of light intensity on photosynthetic activity in two different woodland plants.

a. At a light intensity of 10, what is the photosynthetic activity of plant A? (1)

b. Why would plant A be better suited to living in the shade than plant B? (1)

17


c. Suggest a reason why photosynthetic activity declined at higher light intensities in both plants(1)

d. Suggest how measuring photosynthetic activity could be measured in these plants. (2)

12. The graph below shows the concentration of carbon dioxide in a crop of plants in a field.

a. At what height above the ground is there the lowest concentration of carbon dioxide. (1)

b. At what height above the ground does the maximum rate of photosynthesis occur? (1)

c. Explain why the concentration of carbon dioxide is highest at ground level? (2)

13. Light is often a limiting factor for photosynthesis.a. (a) What is meant by a limiting factor? (1)

b. (b) Why do plants sometimes stop photosynthesising on a very hot, dry day? (2)

18


14. Light can be a limiting factor in photosynthesis. The following graph shows the effect of increasing light intensity on the uptake of carbon dioxide by a green plant.

a. Within what range of light intensities is carbon dioxide taken in by the plant? (1)

b. Suggest why the graph levels off at high light intensities. (1)

c. Explain why at low light intensities carbon dioxide is given out by the plant. (2)

15. The graph shows the rates of oxygen release and uptake in some plants. The plants were placed for 12 hours in the dark followed by 12 hours in the light in a laboratory.

a. What processes take place in the plants during the 12 hours of light? (1)

b. Calculate the volume of oxygen taken up by during the first 6 hours of darkness. (1)

19


The table shows the results of an experiment to measure the rate of photosynthesis under different conditions.

c. Plot a line graph to show the rate of photosynthesis varies with carbon dioxide concentration. Join your points with straight lines. Make a to distinguish between the different light intensities. (8)

d. Use the graph to determine:i. At what concentrations is

carbon dioxide a limiting factor for both light intensities? (1)

ii. At what concentration does carbon dioxide cease being the limiting factor under high light intensity? (1)

iii. The increase in photosynthesis between low and high intensity at 0.12% carbon dioxide concentration. (1)

20


16. The diagram shows a section through a leaf.

a. Label structures A and B.(2)

b. Cells in the palisade layer contain more chloroplasts than cells in the spongy layer. Explain why this is an advantage to the plant. (4)

17. The diagram (below) to the left a section through a leaf. The different parts of the leaf have been labelled A, B, C and D. The diagrams (below) to the right show three types of leaf cell.

a. Match the cell type to the location. (3)b. State the name of each type of cell. (3)

21


18. After photosynthesis plants may transport excess sugar out of the leaf to other parts of the plant that require it or store it in the leaf as starch.a. Name the tissue in a plant that transports sugar. (1)

b. Before an experiment to show that light is needed for photosynthesis, a plant was put in the dark for 48 hours. What happens to starch stored in leaves during this time? (2)

19. The diagram shows parts of a plant cell. Use the diagram and your understanding to complete the table. (4)

20. Explain how the structure of the leaf is adapted for its role as the organ of photosynthesis. (6)

21. Some plants lose their leaves in cooler months. Suggest two reasons why some plants lose their leaves in cooler months. (2)

22

feature name of partmade of cellulosecontains a green substancecalled chlorophyllalso found in animal cells

1 cytoplasm23


22. The diagram shows a potato plant.

a. During photosynthesis, substances which enter or leave the plant are shown by the arrows on the diagram. Label the diagram at E, F and G to show the substances entering or leaving the plant. (3)

b. Potato plants produce storage organs called tubers. Some of the glucose in the tubers is used for respiration. State two uses of glucose in the tubers, apart from respiration. (2)

c. Which minerals does the potato plant need for:i. Growth (1)

ii. Photosynthesis (1)

d. Describe how are mineral ions taken into the plant. (4)

23


23. The graph shows the relationship between the rate of ion absorption by the roots of plants and the concentration of oxygen that is available.

a. What is the rate of ion absorption at an oxygen concentration of 40%? (1)

b. Use the data in the graph to describe the relationship between the rate of ion absorption and the concentration of oxygen. (3)

c. Name the process by which mineral ions enter a plant. (1)

d. Explain why the rate of ion absorption changes with oxygen concentration. (2)

e. Between oxygen concentrations of 80% and 90% there is no increase in the rate of absorption. Suggest a reason for this. (2)

24


24. Plants require magnesium ions for healthy growth.a. Which molecules in a plant contain magnesium ions? (1)

b. Give one change in the appearance of a plant that would show it was not absorbing enough magnesium ions. (1)

25. The diagram shows a pea plant.a. State TWO ways in which the roots helps the plant to live. (2)

b. Complete the equation for photosynthesis. (2)

___________________ + carbon dioxide glucose + ______________________

26. The diagram shows a leaf of a type of carnivorous plant. The end of the leaf forms a pitcher, which attracts insects. When insects enter the pitcher, they fall to the bottom and are digested by a liquid. When their bodies are digested, minerals are released and absorbed by the plant. Carnivorous plants usually grow in places where the soil lacks certain minerals.

a. Name the substance in the liquid which digests the trapped insects. (1)

25


b. Suggest why the plant grows better if it digests insects. (1)

27. Plants A and B were used in an experiment. Both plants A and B were kept on a sunny windowsill. Their growth was measured. The results are shown in the table.

a. Complete the table to show the amount of growth in the stem of plant B. (1)

b. Explain why plant A grew more than plant B. (2)

c. Photosynthesis traps light energy in glucose. What is produced as a by-product? (1)

26


28. The table below shows the results of an investigation to measure the mass of sugar in leaves at different times of the day.

a. State the time of the day where the mass of sugar is at it’s maximum. (1)

b. Suggest reasons why sugar is at it’s maximum mass at this time. (2)

c. Explain why the mass of sugar fell between 8.00 p.m. and 12 midnight. (2)

29. The diagram below shows an experiment to measure how the rate of photosynthesis is affected by light intensity.

a. Suggest how you could measure the rate of photosynthesis.

(1)

b. If the lamp is moved closer to the plant what factors will cause an increase in the rate of photosynthesis? (2)

27


30. Photosynthesis takes place in green plants.a. Name the substance that combines with water in photosynthesis. (1)

b. Where does water enter the plant? (1)

c. Name the products of photosynthesis. (2)

31. Variegated leaves have areas that are green and areas that are white. Some students used variegated leaves to investigate photosynthesis. They covered a variegated leaf with a black paper shape. The leaf was left in a sunny place. They tested the leaf for starch. The results were compared with a leaf that was not covered.

Explain why starch was present in only one of the tests. (4)

32. The diagram shows a computer being used as a data-logger to record oxygen and light levels over a 24 hour period.

a. Give an advantage of using a oxygen probe as opposed to counting the bubbles. (1)

b. Give advantages of using a data logger in this experiment. (2)

28

Documents

iheartbio.weebly.comiheartbio.weebly.com/uploads/1/3/4/2/13422000/2enutriti… · Web view2.18 write the word equation and the balanced chemical symbol equation for ... 117 from