form4(BIOLOGY) chap 2 pt1
- 1. CHAPTER 2 : CELL STRUCTURE & CELL ORGANISATION 2.1 Cell Structure & Function 2.2 Cell Organisation
- 2. 2.1 CELL STRUCTURE & FUNCTION Learning Outcomes : 2. Draw & label an animal cell and a plant cell 3. Identify the cellular components of an animal cell & a plant cell 4. State the functions of the cellular components in an animal and a plant cell 5. Compare & contrast an animal cell with a plant cell 6. Relate the density of certain organelles with the functions of specific cells.
- 4. HISTORY Robert Hooke (1665) was first discovered the cell structure of plant He examined fine slices of cork with a primitive microscope He saw many ‘box-like’ structures , then he called ‘cells’, from Latin for ‘little rooms’.
- 5. THE CELL THEORY (Schleiden M & Schwann T) All living organisms are made up of one or more cells New cells are formed by the division of pre-existing cells Cells contain genetic material of an organism which is passed from the parent cells to daughter cells Cells are the basic unit of structure & function in living things
- 8. ORGANELLES specialised structures which are each surrounded by its own membrane & perform specific function
- 9. PLASMA MEMBRANE Thin, semi-permeable Made of protein, lipid Controls the movement of substances in and out of the cell Non-organelle
- 10. CYTOPLASM Jelly-like substance that contains water & mineral salts Contains organelles and food such as carbohydrates (glucose) Medium for metabolic reactions Supplies the substances required by organelles Non-organelle
- 11. CELL WALL Thick layer outside the plasma membrane Made up of cellulose, fully permeable Maintains the shape of the plant cells Provides mechanical support Non-organelle
- 12. NUCLEUS Spherical shape with double membrane Contains nucleolus, chromosomes, nucleoplasm & nuclear membrane Controls & regulates all the activities of cell Contain the heredity factors responsible for the traits
- 13. RIBOSOME Small particles consisting of RNA Exists freely in the cytoplasm or on the surface of the endoplasmic reticulum Synthesis of protein
- 14. ENDOPLASMIC RETICULUM A system of membrane- enclosed tubules closely packed together and continuous with the nuclear membrane RER has ribosome, SER does not have Transport system for protein & lipids within the cell RER transport protein to other part of cell SER stimulates the synthesis of lipids & cholesterol & transport within the cell
- 16. GOLGI APPARATUS Vacuolar region surrounded by a complex meshwork of vesicles budding off at its end Received protein & lipids from ER & modify them to form specific secretion such as enzymes & hormones Pack the secretions formed into secreting vesicles & transport them to plasma membrane to be secreted Controls the secretory activity of cells Formation of lysosomes
- 18. VACUOLE Filled with cell sap, surrounded by semi- permeable membrane called the tonoplast Contain water, sugar & dissolved minerals Maintain turgidity of cells in plants
- 19. MITOCHONDR IA Rod-shape with a double membrane Outer membrane is smooth, inner membrane is folded to form cristae Known as ‘power- house’ of the cell Releases energy as it is the site for aerobic respiration
- 21. CHLOROPLAST Disc-shape organelle with a double membrane Consist of an orderly arrangement of grana within the stroma. Granum contains chlorophyll Site of photosynthesis Trapped light energy and change it into chemical energy
- 22. LYSOSOMES Membrane-bound vesicles found in animal cells Contain enzymes which control breakdown of protein & lipids Contain enzymes that digest aged or defective cell components or materials taken in by the cell from its environments such as food particles or bacteria.
- 23. CENTRIOLES A pair of small cylindrical structures (microtubules ) Form spindle fibre for cell
- 24. COMPARE & CONTRAST ANIMAL CELL SIMILARITIES PLANT CELL A plasma membrane surrounding the cytoplasm Both contain nucleus & cytoplasm Both contain organelles such as mitochondria, ER, Golgi apparatus & ribosomes
- 25. ANIMAL CELL DIFFERENCES PLANT CELL Smaller than plant cell SIZE Larger than animal cell Irregular shape SHAPE Often regular in shape Absent CELL WALL Present Absent CHLOROPLAST Present No large vacuoles. If VACUOLES Large central vacuole present, small & filled with cell sap numerous. In a form of glycogen in FOOD STORAGE In a form of starch liver & muscle tissues Present CENTRIOLES Absent Some animal cell have CILIA & FLAGELLA Absent cilia or flagella
- 26. RELATIONSHIP BETWEEN THE STRUCTURE OF AN ANIMAL CELL & A PLANT CELL
- 27. The number of specific organelles in a cell varies on the type of cell and its function. Active cell many mitochondria to provide enough energy for its activities. Eg. : sperm cells, flight muscle cell (insects & birds) Cell in meristems of plant shoot & root Green plants more chloroplasts to carry out photosynthesis such as palisade mesophyll cells and spongy mesophyll cells, also guard cells.
- 28. EXERCISE 2.1 1. What are the organelle structures of a cell? 2. What are the functions of each structure describe above?