1. The basic structure of a cell

2. Introduction Cells are the basic units of organisms –Cells were first observed by scientist under microscope Two basic types of cells –Plant cells –Animal cells

3. Plant cell –Made of cellulose which forms very thin fibres –Strong and rigid Cell wall

4. Plant cell Cell wall –Protect and support the enclosed substances (protoplasm) –Resist entry of excess water into the cell –Give shape to the cell

5. Plant cell Cell wall –Large spaces present between cellulose fibres  freely permeable

6. Plant cell Cell membrane –Lies immediately against the cell wall –Made of protein and lipid

7. Plant cell Cell membrane –Can control the movement of materials into and out of the cell  Selectively permeable

8. Plant cell Cytoplasm –Jelly-like substance enclosed by cell membrane –Provide a medium for chemical reactions to take place

9. Plant cell Chloroplasts –Contain the green pigment chlorophyll To trap light energy to make food by photosynthesis –Contain starch grains (products of photosynthesis)

10. Plant cell Mitochondrion –Rod-shape –For respiration to take place Active cells (sperms, liver cells) have more mitochondria

11. Plant cell Non-living granules –Starch granules –Oil droplets –Crystals of insoluble wastes

12. Plant cell Nucleus –Control the normal activities of the cell –Bound by a nuclear membrane –Contains thread- like chromosomes Chromosomes carry genes

13. Plant cell Vacuole –Surrounded by tonoplast –Contains cell sap a solution of chemicals (sugars, proteins, mineral salts, wastes, pigments)

14. Different kinds of plant cells

15. Animal cell No cell wall and chloroplast Stores glycogen granules and oil droplets in the cytoplasm mitochondrion nucleus oil droplet glycogen granule cell membrane cytoplasm

16. Different kinds of animal cells

17. Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

18. Differences between plant cells and animal cells Animal cellsPlant cells Relatively smaller Irregular in size No cell wall Vacuole small or absent Glycogen granules as food store Nucleus at the centre Relatively larger Regular in size Cell wall present Large central vacuole Starch granules as food store Nucleus near cell wall

19. Microscope Instrument for observing small objects

20. Different parts of a microscope EyepieceBody tube Coarse adjustment Fine adjustment Objective Nose piece Stage Clip Condenser Condenser adjustment Diaphragm Mirror Arm

21. The cell as the basic unit of life Cell is the smallest unit of living organisms Unicellular organisms are made of one cell only The cells of multicellular organisms are specialized to perform different functions –e.g. mesophyll cells and root epidermal cells in plants

22. Levels of organisation Cells are group together and work as a whole to perform special functions

23. Tissue A group of similar cells to perform a particular job –Animals: epithelial tissue, muscular tissue –Plants: vascular tissue, mesophyll

24. Organ Different tissues group together to carry out specialized functions –Heart: consists of muscles, nervous tissue and blood vessels –Leaf: consists of epidermis, mesophyll and vascular tissue

25. System Several organs and tissues work together to carry out a particular set of functions in a co-ordinated way –Human: digestive, respiratory, excretory, circulatory and reproductive systems –Plant: root and shoot systems