GCSE Biology Topic 1 - Cells

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Cell divsion

Osmosis

Cells

Animal Cells

Plant Cells

Cell parts

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KS3 Cells Topic BookletAnimal and Plants Cells

Big Picture

Robert Hooke was the first person to see cells in 1665, although he had no idea of their significance at the time. He happened to look at a very thin slice of cork (from a tree) and saw that it was made up of tiny compartments, which he called ‘cells’ (either after the cells made by bees, or after the little rooms or ‘cells’ in which monks live).

Why are they important?

Cells are the building blocks of life. All living things are made of cells. There are many different types of cells, however most have the same key features. Some cells are specialised to allow them to carry out a particular job or function.

Diagrams of cells

KS3 Cells Topic Booklet 1

1. Label this simplified diagram of an animal cell

3. What are the similarities (the same) between animal and plant cells?Both plant and animal cells have a nucleus, cell membrane, cytoplasm and mitochondria and ribosomes.

4. What are the differences between animal and plant cells?

Plant cells have 3 extra sub-cellular structures that an animal cell does not – cell wall, permanent vacuole and chloroplasts.

2. Which sub-cellular structures are missing from both of these diagrams that you have learned about this year?

Mitochondria and ribosomes

Each part of the cell has a specific role and each role is required to keep the cell alive. The table below shows the part of the cell along with the cell type and its purpose. You need to know these and will be quizzed on them in the future!

Part of the Cell Type of cell Function or Job

Nucleus Animal and plant Controls the activities of the cell. Contains all the genetic information.

Cell membrane Animal and plant Gives the cell a shape and controls the substances that enter and leave the cell.

Cytoplasm Animal and plant The jelly substance where most of the chemical reactions take place.

Cell wall Plant Made of cellulose. Gives the cell a more definite shape/structure.

KS3 Cells Topic Booklet 2

2. Label this simplified diagram of a plant cell

cytoplasmCell membrane

Nucleus

cytoplasm Cell membrane

Nucleus Cell wall

Chloroplast

Permanent vacuole

Vacuole Plant Filled with cell sap which helps to keep the cells shape.

Chloroplast Plant Filled with chlorophyll, which absorbs light energy for photosynthesis.

Ribosome Animal and Plant Site of protein synthesis.

Mitochondria Animal and Plant The site of aerobic respiration and therefore where energy in released.

3. In your own words (not copied form above but means the same), what is the job of the nucleus?

Contains DNA so controls the activities of the cell.

4. What is the job of the cell membrane?

Controls which substances can enter and exit the cell.

5. What is the job of the cytoplasm?

Where most chemical reactions happen.

6. What is the job of the cell wall?

To provide strength and support to the cell.

7. What is the job of the vacuole?

Filled with cell sap, keeps the cell rigid.

8. What is the job of the chloroplast?

Absorbs sunlight for photosynthesis.

9. Name the fluid space where all the structures lie

cytoplasm

10. Name two structures found in animal and plant cells

Cell membrane, cytoplasm, nucleus, mitochondria, ribosomes

11. Give the function of the mitochondria

Where aerobic respiration takes place and so energy in released.

12. Name two structures only found in plant cellsPermanent vacuole, chloroplasts, cell wall

KS3 Cells Topic Booklet 3

13. Which structure contains chlorophyll?

Chloroplasts

Seeing Cells

We use microscopes (micro- meaning small and –scope meaning an instrument to view) to see cells.

The MICROSCOPE is an instrument that produces a magnified image of objects that are too small to be seen by the naked eye.

You do need to know the parts of a microscope:

Method for using microscope

Place cells on glass slide and secure on STAGE

Look down EYE PIECE LENS and make sure MIRROR is reflecting light up (so you can see light and not just black)

Use the COARSE FOCUS (big change) and FINE FOCUS (small change) to bring image to focus.

Change OBJECTIVE LENS to zoom in and out more.

14. What is the purpose of the mirror?

To provide a light source to pass through the specimen.

15. Why are there a fine focus and a coarse focus?To allow the image to be focussed by making big and small changes to the focus of the lens.

16. Why might you change the objective lens?To increase/change the magnification

KS3 Cells Topic Booklet 4

17. Why do we need microscopes?

So we can see things that are too small to see with the naked eye.

18. What kind of jobs might use a microscope? Why would they need a microscope?Microbiologist – to see micro-organisms that are too small to see otherwise Medical professionals – for examining human cells such as blood and other tissues There are many other examples you could have come up with too these are just two ideas.

19. What parts of a cell are common in both animal and plant cells? What is the purpose of these cell parts?MRCCN – Mitochondria, Ribosomes, Cell membrane, Cytoplasm, Nucleus Mitochondria – site of aerobic respiration and where energy is released Ribosomes – site of protein synthesis Cell membrane – controls what enters and exits the cell Cytoplasm – where most chemical reactions take place Nucleus – contains DNA and controls the activities of the cell

Specialised cells

A specialised cell is a cell that performs a specific function. The structure of the cell helps it to carry out this function.

The table on the next page contains some information about different specialised cells. This is some more information you need to know and learn. You will be quizzed on this in some upcoming lessons and this is vital for GCSE Biology!

Use the information in the table to answer the questions below.

KS3 Cells Topic Booklet 5

20. How is a sperm cell specialised?

Tail for swimming, nucleus with half the set of genetic information, streamlined and has lots of mitochondria.

21. Where are palisade cells found?The top of a leaf in plant.

22. What is the purpose of a root cell?

Absorbs water and nutrients from the soil to then be transported around the rest of the plant.

23. Why are red blood cells so good at carrying oxygen around the body?

Because they contain haemoglobin which the oxygen molecule binds to travel around the body. They also have a biconcave disc shape which allows the blood cells to travel through narrow blood vessels.

24. What are the similarities between an egg and a sperm cell? What are the differences?The similarity between both cells is that they both have half a set of genetic information in the nucleus. The differences are the sperm cell is much smaller and a different shape. The sperm cell has adaptations which allow it to move, such as the tail, where as the egg cell does not.

25. Are all cells specialised?No – stem cells are not specialised.

Complete the sentences:

26. Specialised cells are very important to humans because they are essential to humans developing specialised tissues and organs to perform the functions a complex organism like humans need.

27. Specialised cells are very important to humans but they are also important to plants too as a plant is also a multicellular organism that needs different tissues to perform a variety of functions.

28. Specialised cells are very important to humans so lots of research goes into developing stem cells into specific specialised cells for medical treatments.

Statement True False

29 Another name for the egg cell is the ‘ovum’

30 The function of a red blood cell is to carry oxygen and carbon dioxide around the body. (only carry oxygen)

31 Palisade cells are found in the roots of plants. (found in the leaves)

32 Sperm cells are only found in male testes.

33 Root hair cells contain chloroplasts. (they do not need any as chloroplasts absorb sunlight and there is no sunlight underground)

KS3 Cells Topic Booklet 6

34 Red blood cells contain chemicals called chlorophyll which sticks to oxygen molecules. (contain haemoglobin not chlorophyll)

35 Egg cells contain a full set of genes from the mother which are then passed on to the offspring. (contain half a set of genes)

36 One adaptation of a sperm cell is that it has an streamline shape to help it swim to the egg

37 The function of the palisade cell is to carry out photosynthesis. It has many chloroplasts because this is where photosynthesis happens within a cell.

38 Root hair cells form the hair on our heads. (they are found in the roots of plants)

Requirements for life

How is a mixture of chemicals in a chemistry lesson and different to a mixture of chemicals human brain? We need to define when something is alive and when something is not alive. For example, we are alive but the wood in the desk you are writing this at is not alive. In order for something to be alive it must do all of the following things, which are arrange in an acronym MRS GREN.

M – Movement. All living things move. Animal move around and pant grow towards the sun or deeper in to soil

R – Reproduction. Animals have babies: some lay eggs and the babies hatch out of these. Plants produce seeds and new plants grow from them.

S – Sensitivity. All living things respond to changes in their environment and react to them. For example, humans and plant react to weather and sunlight.

G – Growth. All living things grow, even if it is just a small amount.

R – Respiration. Living things use oxygen to breakdown their food to release energy. This occurs in all cells

E – Excretion. Living things produce waste. Getting rid of this waste is called excretion.

N – Nutrition. Food is used by living things to give them energy such as the sun or food we eat.

39. Name the parts of a microscopeEye piece lens, objective lens, stage, stage clips, mirror/light source, arm, base, course focussing wheel, fine focussing wheel.

40. What does Magnification mean?Enlarging the apparent size of an object.

41. What does focus mean?Making an image clear to see.

42. How do you focus an image using microscope?By adjusting the course and fine focussing wheels.

KS3 Cells Topic Booklet 7

43. How do you increase the magnification of an image

Change the objective lens to a higher magnification.

44. How do you record an image from a microscope?

You can make an observational drawing of what you see underneath he microscope.

45. What is a cell?

The basic building block of life

46. Draw and label an animal cell – you may have drawn cells that look similar to either of these.

KS3 Cells Topic Booklet 8

47. Draw and Label a plant cell - you may have drawn cells that look similar to either of these.

48. What are the key structural differences between an animal cell and a plant cell?

A plant cell has a cell wall, permanent vacuole and chloroplasts whereas an animal cell does not.

49. What is a nucleus and what is its function?

The nucleus is a sub-cellular structure found in all eukaryotic cells and it contains DNA (genetic material) and controls the activities of the cell.

50. What is a cell membrane and what is its function?

A cell membrane is a sub-cellular structure found in all cells and it controls what enters and exits the cell.

KS3 Cells Topic Booklet 9

51. What is a cytoplasm and what is its function?

A cytoplasm is a sub-cellular structure found in all cells and it is where most chemical reactions happen.

52. What is a mitochondria and what is its function?

A mitochondria is a sub-cellular structure and it is the site of aerobic respiration and therefore where energy is released.

53. What is a ribosome and what is its function?

A ribosome is a sub-cellular structure where protein synthesis occurs.

54. What is a cell wall and what is its function?

A cell wall is found in plant cells and it is made from cellulose, it provides strength and support to the cell.

55. What is a chloroplast and what is its function?

A chloroplast is a sub-cellular structure found in plant cells. It contains chlorophyll and absorbs sunlight for photosynthesis.

56. What is a vacuole and what is its function?

A permanent vacuole is a structure found in plant cells, it contains cell sap and helps to the keep the cell firm and rigid.

57. Give two examples of specialised cells in animals

Any two from; sperm cell, egg cell, red blood cell.

58. What is the function of a Red Blood Cell (RBC)?

To transport oxygen around the body

59. How does the shape of the Red Blood Cell support its function?

It has a biconcave disc shape which allows it to fit through blood vessels.

60. How does Haemoglobin support the role of the Red Blood Cell?

Oxygen binds to the haemoglobin within the red blood cell and can be transported around the body.

61. What is the function of a Root Hair Cell?

To absorb water and nutrients from the soil to then be passed around the plant.

62. How does a Root Hair Cell’s surface area support its function?

It has a large surface area, this allows it to absorb more water and nutrients.

63. Why does the Root Hair Cell not contain chloroplasts?

Because it is underground in the roots and there is no sunlight there. The job of the chloroplasts is to absorb sunlight for photosynthesis so they are not needed in a root hair cell.

KS3 Cells Topic Booklet 10

64. What is the function of a Palisade Cell?

To carry out photosynthesis for the plant.

65. Why is the Palisade Cell suited to its function?

It has lots of chloroplasts so it can absorb more sunlight and complete more photosynthesis.

66. Where in the leaf are Palisade Cells found and how does this help them to carry out their function?

It is found towards the top of the leaf which means it has more access to sunlight for photosynthesis

67. What are the 7 things that all living things do?

MRS GREN/ MRS NERG

M – Movement. All living things move. Animal move around and pant grow towards the sun or deeper in to soil

R – Reproduction. Animals have babies: some lay eggs and the babies hatch out of these. Plants produce seeds and new plants grow from them.

S – Sensitivity. All living things respond to changes in their environment and react to them. For example, humans and plant react to weather and sunlight.

G – Growth. All living things grow, even if it is just a small amount.

R – Respiration. Living things use oxygen to breakdown their food to release energy. This occurs in all cells

E – Excretion. Living things produce waste. Getting rid of this waste is called excretion.

N – Nutrition. Food is used by living things to give them energy such as the sun or food we eat.

KS3 Cells Topic Booklet 11