1. IGCSE Biology
Cells
Identify the key features of plant and animal cells
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2. Learning Objectives Identify the main structures found in plant cells
Identify the main structures found in animal cells
Compare plant cells with animal cells
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3. Cells – The Building Blocks Of Life
All living organisms are composed of cells.
The simplest organisms are made of one single cell.
More complex organisms like animals and plants are made of many cells and are called multicellular organisms.
In multicellular organisms there are many different types of cells that are specialised to carry out particular functions.
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4. The Light Microscope
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5. Animal Cell 3
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6. Animal Cell
Cell Membrane
Cytoplasm
Nucleus
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7. A general animal cell Cell membrane Cytoplasm Nucleus Mitochondria
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8. Plant Cell 6
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9. A general plant cell Cell wall Cell membrane Mitochondria Vacuole
Cytoplasm
Chloroplast
Nucleus
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10. Additional features found in plant and animal cells
Ribosomes
Ribosomes
Ribosomes are important for the manufacture of proteins
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11. Additional features found in plant and animal cells
Rough endoplasmic reticulum
Ribosomes
Ribosomes
Rough endoplasmic reticulum
Rough endoplasmic reticulum-involved in the modification and transport of proteins
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12. Additional features found in plant and animal cells
Rough endoplasmic reticulum
Ribosomes
Ribosomes
Vesicles
Rough endoplasmic reticulum
A membrane bound bag that contains fluid
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13. Nucleus Largest organelle. Controls the activities of the cell.
Contains chromosomes.
Chromosomes carry genes.
The genes determine which proteins the cell can make.
Nucleus
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14. Cell Surface Membrane
Forms a boundary between the cytoplasm and the outside of the cell.
Some chemicals can pass through this barrier and the cell can control what comes in and out.
It is selectively permeable.
Cell membrane
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15. Cytoplasm
Jelly like substance which contains all of the organelles (e.g. nucleus and mitochondria).
Many of the cell’s chemical reactions take place in the cytoplasm.
These are called metabolic reactions.
Cytoplasm
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16. Mitochondria Carry out some of the reactions of aerobic respiration.
Therefore releasing energy for the cell.
Cells that have a high demand for energy usually have many mitochondria, such as muscle cells.
Mitochondria
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17. Cell Wall Found only in plant cells.
It is made of a non-living material called cellulose.
Helps the cell keep its shape.
It is freely permeable.
Cell wall
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18. Chloroplast Found in some plant cells. Contains chlorophyll.
Chlorophyll is a green pigment.
It absorbs light energy to make food in the process of photosynthesis.
Chloroplast
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19. Vacuole Found only in plant cells. Filled with cell sap.
Cell sap is a store of dissolved sugars, mineral ions, and other solutes.
Helps keep the cell’s shape.
Vacuole
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20. Rough endoplasmic reticulum
A membrane bound structure that is important for the modification and transport of proteins. The RER is encrusted with ribosomes
Ribosomes
Small organelles that can be free floating in the cytoplasm or bound to RER. Important for the synthesis of proteins
Vesicles
Membrane bound bags that contain fluids or chemicals
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21. Summary Cell structures and their functions
Plant or animal cell
Function
Nucleus
Both
Controls the activity of the cell using genes
Cell Membrane
Cytoplasm
Mitochondria
Cell Wall
Chloroplast
Large Vacuole
Endoplasmic reticulum
Ribosomes
Vesicles
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22. Summary Cell structures and their functions
Plant or animal cell
Function
Nucleus
Both
Controls the activity of the cell using genes
Cell Membrane
Controls what enters and leaves the cell
Cytoplasm
Location of cell metabolic reactions
Mitochondria
Site of aerobic respiration- cells such as sperm and liver cells have lots of these
Cell Wall
Plant only
Made of cellulose, gives cell strength
Chloroplast
Site of photosynthesis
Large Vacuole
Contains cell sap which helps keep cell’s shape
Endoplasmic reticulum
Modification ad transport of proteins
Ribosomes
Synthesis of proteins
Vesicles
Membrane bound bags containing fluids
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23. IGCSE Biology
(S2) 2 Specialized Cells
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24. Learning Objectives
Can you explain the organisation of an organism using the following terms: organelles, cells, tissues, organs and organ systems?
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25. Cell Division
Multicellular organisms begin life as a single fertilised egg cell called a ZYGOTE.
It then divides over and over again by MITOSIS
Zygote
Embryo
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26. Differentiation
As the developing embryo grows, cells become specialised to carry out particular roles.
This is called differentiation and is controlled by genes.
As all cells have the same genes, some must be switched on and some switched off for this to work. This is discussed further in the IGCSE course.
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27. Specialised cells
Here are a few examples of specialised cells that you will meet throughout the IGCSE Biology course.
They will be mentioned briefly here as they will be explained fully in each relevant section.
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28. Specialized cells
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29. Specialized cells Ciliated cell Found in trachea and oviducts
Specialised by its cilia- tiny hairs that move in waves
Function- to move mucus along the trachea and to waft the ovum along the oviduct
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30. Specialized cells
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31. Specialized cells Root hair cell Found on the roots of plants
Specialized by its protrusion that increases surface area
Function- To absorb water and minerals
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32. Specialized cells
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33. Specialized cells Muscle Cell Found in muscles
Specialized by its protein fibers found in the cytoplasm and their ability to contract
Function- muscle contraction
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34. Specialized cells
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35. Specialized cells Red Blood Cell Found in plasma
Specialized by a flattened disc shape, large surface area, lack of nucleus and haemoglobin content
Function- to transport oxygen
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36. Specialized cells Xylem Found in the roots and stem of plants
Specialized hollow tubes with no end plates, thickened with lignin (lignified)
Function- to transport water and dissolved minerals
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37. Nerve cell (Neurone)
Very long cell for carrying impulses around the body along its axon.
Insulated by a myelin sheath to make the signal travel quicker.
Dendron
Cell body
Axon
Myelin sheath
Dendrites
Muscle
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38. Sperm cell Sperm cells have a tail for swimming.
The head contains the genes from the father in the nucleus.
The acrosome digests its way into the egg for fertilisation.
Acrosome
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Tail
Nucleus

39. Palisade cell This cell is found in the leaves of plants.
It is packed full of chloroplasts for photosynthesis.
It is a regular shape in order to pack many into the leaf.
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40. Tissues and organs
Organelles are the individual parts that make up a cell, e.g. Membrane, nucleus Similar cells that are grouped together are called tissues- skin, muscle, blood Similar tissues working together form an organ- heart, lung, leaf Organs that work together to share the workload are called organ systems- circulatory, reproductive, digestive
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41. Organelles Cells Tissues Organs Organ Systems
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42. Some of the key major human organs
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43. These will all be covered in detail in the rest of IGCSE
The 7 main organ systems
Digestive
Respiratory
Circulatory
Excretory
Nervous
Endocrine
Reproductive
These will all be covered in detail in the rest of IGCSE
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44. Division of Labour
By working together organs are able to share the workload, we often refer to this as division of labour
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45. IGCSE Biology Magnification Calculate the magnification of an image
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Calculate the magnification of an image

46. Learning objectives Use the formula M= I/A
Draw an image as seen under a microscope and calculate the mahgnification
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47. Magnification
Calculate magnification if A is 10mm in width and B 30mm in width B A
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48. Magnification
1mm µm
Calculate the magnification in micrometres of image B if it is 20cm at its longest point and the actual organism is 4.5cm B A
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49. Calculating magnification
Draw an image as seen under a microscope and calculate the magnification
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