home - gcse exams preparation · web view2020/04/04 · word equation for photosynthesis. water +...

TRANSPORT IN CELLS – HIGH DEMAND

Q1. Plant roots absorb water from the soil by osmosis.

(a) What is osmosis?

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(b) The image below shows part of a plant root.

The plant root is adapted for absorbing water from the soil.

Use information from the diagram to explain how this plant root is adapted for absorbing water.

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(Total 6 marks)

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Q2. (a) The diagram shows four ways in which molecules may move into and out of a cell. The dots show the concentration of molecules.

The cell is respiring aerobically.Which arrow, A, B, C or D, represents:

(i) movement of oxygen molecules; __________

(ii) movement of carbon dioxide molecules? __________(2)

(b) Name the process by which these gases move into and out of the cell.

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(c) Which arrow, A, B, C or D, represents the active uptake of sugar molecules by the cell?

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Explain the reason for your answer.

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(Total 5 marks)

Q3. Cells, tissues and organs are adapted to take in different substances and get rid of different substances.

The table shows the concentration of four ions outside cells and inside cells.

IonConcentration

outside cells in mmol per dm3

Concentration inside cells in mmol per dm3

Sodium 140 9

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Potassium 7 138

Calcium 2 27

Chloride 118 3

(a) Use information from the table above to complete the following sentences.

Sodium ions will move into cells by the process

of __________________________________ .

Potassium ions will move into cells by the process

of __________________________________ .(2)

(b) Some students investigated the effect of the different concentrations of sugar in four drinks, A, B, C and D, on the movement of water across a partially permeable membrane.

The students:

• made four bags from artificial partially permeable membrane

• put equal volumes of 5% sugar solution in each bag

• weighed each bag containing the sugar solution

• placed one bag in each of the drinks, A, B, C and D

• after 20 minutes removed the bags containing the sugar solution and weighed them again.

The diagram below shows how they set up the investigation.

(i) The bag in drink A got heavier after 20 minutes.

Explain why.

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(ii) In which drink, A, B, C or D, would you expect the bag to show the smallest change in mass?

Tick (✔) one box.

A B C D

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(iii) Explain why you think the bag you chose in part (b)(ii) would show the smallest change.

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(Total 8 marks)

Q4. The drawing shows part of a root hair cell.

(a) Use words from the list to label the parts of the root hair cell.

cell membrane cell wall cytoplasm nucleus vacuole(4)

(b) The diagram shows four ways in which molecules may move into and out of a cell. The dots show the concentration of molecules.

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The cell is respiring aerobically.Which arrow, A, B, C or D represents:

(i) movement of oxygen molecules; __________

(ii) movement of carbon dioxide molecules? __________(2)

(c) Name the process by which these gases move into and out of the cell.

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(Total 7 marks)

Q5. Some students set up this experiment to investigate osmosis. They filled two pieces of dialysis [visking] tubing with different liquids and left them both in a beaker of 5% sucrose solution for an hour.

(a) Describe and explain the likely results after one hour.

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(b) Describe two examples where osmosis is used in living things.

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(Total 8 marks)

Q6. Some students set up the equipment below to investigate osmosis.

(a) What is osmosis?

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(b) (i) What will happen to the water level in the capillary tube during the

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investigation because of osmosis?

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(ii) Use your knowledge of osmosis to explain why this happens.

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(Total 6 marks)

Q7. The small intestine is lined with millions of villi.The diagram shows the structure of a villus.

In the small intestine, some of the products of digestion are absorbed into the blood by active transport.

(a) Explain what is meant by active transport.

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(b) How do microvilli and mitochondria help in the active transport of the products of digestion from the small intestine into the blood?

Microvilli ___________________________________________________________

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Mitochondria ________________________________________________________

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(Total 4 marks)

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Q8. Cells contain a solution of salts and sugars.

A student is investigating how cells change when they are put into water.

(a) The student:

• looks at a plant cell using a microscope

• adds water to the cell.

The plant cell swells up.

Explain why, as fully as you can.

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(b) When animal cells are put in water, they swell up, and then burst.When plant cells are put in water, they swell up, but do not burst.

How does the structure of plant cells prevent them from bursting?

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(Total 4 marks)

Q9. The human lung has about 80 million alveoli.The diagram shows some alveoli in a human lung.

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(a) Give three features of the alveoli that allow large amounts of oxygen to enter the blood.

1. _________________________________________________________________

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2. _________________________________________________________________

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3. _________________________________________________________________

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(b) (i) Name the process by which oxygen passes from the air into the blood.

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(ii) Breathing allows large amounts of oxygen to enter the blood.

Explain how breathing does this.

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(Total 6 marks)

Q10. In this question you will be assessed on using good English, organizing information clearly and using specialist terms where appropriate.

Diffusion is an important process in animals and plants.

The movement of many substances into and out of cells occurs by diffusion.

Describe why diffusion is important to animals and plants.

In your answer you should refer to:

• animals

• plants

• examples of the diffusion of named substances.

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Extra space _____________________________________________________________

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Q11. The diagram below shows a cross-section of a plant root. The transport tissues are labelled.

(a) (i) What is tissue A?

Draw a ring around the correct answer.

cuticle epidermis xylem

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(1)

(ii) Name two substances transported by tissue A.

1. ____________________________________________________________

2. ____________________________________________________________(2)

(b) Phloem is involved in a process called translocation.

(i) What is translocation?

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(ii) Explain why translocation is important to plants.

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(c) Plants must use active transport to move some substances from the soil into root hair cells.

(i) Active transport needs energy.

Which part of the cell releases most of this energy?

Tick (✓) one box.

mitochondria

nucleus

ribosome

(1)

(ii) Explain why active transport is necessary in root hair cells.

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(Total 9 marks)

Q12. The diagram below shows a single-celled alga which lives in fresh water.

(a) Which part of the cell labelled above:

(i) traps light for photosynthesis

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(ii) is made of cellulose?

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(b) In the freshwater environment water enters the algal cell.

(i) What is the name of the process by which water moves into cells?

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(ii) Give the reason why the algal cell does not burst.

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(c) (i) The alga can photosynthesise.

Complete the word equation for photosynthesis.

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water + _______________ _______________ + oxygen(2)

(ii) The flagellum helps the cell to move through water. Scientists think that the flagellum and the light-sensitive spot work together to increase photosynthesis.

Suggest how this might happen.

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(d) Multicellular organisms often have complex structures, such as lungs, for gas exchange.

Explain why single-celled organisms, like algae, do not need complex structures for gas exchange.

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(Total 11 marks)

Q13. Gas exchange takes place in the lungs.

The diagram shows an alveolus next to a blood capillary in a lung.

The arrows show the movement of two gases, A and B.

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(a) (i) Draw a ring around the correct answer to complete the sentence.

Gases A and B move by

diffusion.

osmosis.

respiration.

(1)

(ii) Gas A moves from the blood to the air in the lungs.

Gas A is then breathed out.

Name Gas A.

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(iii) Which cells in the blood carry Gas B?


platelets red blood cells white blood cells(1)

(b) The average number of alveoli in each human lung is 280 million.

The average surface area of 1 million alveoli is 0.25 m2.

Calculate the total surface area of a human lung.

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Answer ___________________________________ m2

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(c) An athlete trains to run a marathon. The surface area of each of the athlete’s lungs has increased to 80 m2.

Give one way in which this increase will help the athlete.

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(Total 6 marks)

Q14. The image below shows an epithelial cell from the lining of the small intestine.

(a) (i) In the image above, the part of the cell labelled A contains chromosomes.

What is the name of part A?

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(ii) How are most soluble food molecules absorbed into the epithelial cells of the small intestine?


diffusion osmosis respiration

(1)

(b) Suggest how the highly folded cell surface helps the epithelial cell to absorb soluble food.

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(c) Epithelial cells also carry out active transport.

(i) Name one food molecule absorbed into epithelial cells by active transport.

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(ii) Why is it necessary to absorb some food molecules by active transport?

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(ii) Suggest why epithelial cells have many mitochondria.

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(d) Some plants also carry out active transport.

Give one substance that plants absorb by active transport.

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(Total 8 marks)

Q15. In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Plants transport many substances between their leaves and roots.

The diagram below shows the direction of movement of substances through a plant.

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Describe how ions, water and sugar are obtained and transported through plants.

In your answer you should refer to materials moving upwards in a plant and to materials moving downwards in a plant.

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Q16. Capillaries are blood vessels in the body which join the arteries to the veins. They have walls which are one cell thick and so are able to exchange substances with the body cells.

(i) Name two substances that travel from the muscle cells to the blood in the capillaries.

1. _________________________________________________________________

2. _________________________________________________________________(2)

(ii) Glucose is one substance that travels from the blood in the capillaries to the body cells. Explain how this happens.

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(Total 4 marks)

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home - gcse exams preparation · web view2020/04/04 · word equation for photosynthesis. water +...

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