Copyright: Stephanie Teo Acknowledgments: All pictures taken from: Comprehensive Biology: A Course For ‘O” Level by Lam Peng Kwan Unless stated otherwise

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Organisation of the Living Organism

1) Cell – a unit of life - made up of living matter called protoplasm

(protos = first, plasm = form) 2) Protoplasm – jelly-like substance

- chemical reactions take place here - contains 70% water - composition of fat, carbohydrates and proteins may vary. It depends of which

cell protoplasm is found in the body. Example: Protoplasm in muscle cell will contain more carbohydrate to provide energy while protoplasm in the hair will contain more protein (hair is made up of the protein keratin).

- MADE UP OF 3 PARTS : NUCLEUS , CYTOPLASM AND PLASMA MEMBRANE

3) The table below shows the 3 main constituents of protoplasm: Nucleus Cytoplasm Plasma Membrane

-Surrounded by nuclear membrane (separates nucleus from surrounding cytoplasm). Inside nuclear membrane: denser protoplasm called NUCLEOPLASM

-Forms larger part of the cell

-Selectively permeable (DO NOT USE the term PARTIALLY PERMEABLE) It controls substances leaving and entering the cell.

-In the nucleoplasm: a) CHROMATIN (contains DNA and proteins). Chromatin controls cell division, cell repair and cell activities b) Spherical structures called nucleoli (in charge of building proteins)

-Contains: a) Mitochondria (rod shaped structures) [in charge of releasing energy from cell respiration: Look at chapter on Respiration. Energy used for growth and reproduction b) Vacuoles (fluid filled space enclosed by a membrane). Contain water and food substances. c) Centrioles (involved in cell division) d) Golgi Apparatus (involved in sorting and packaging proteins and transporting them to other parts of the cell, synthesize

Copyright: Stephanie Teo Acknowledgments: All pictures taken from: Comprehensive Biology: A Course For ‘O” Level by Lam Peng Kwan Unless stated otherwise

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new cell walls, form lysozymes (small structures that contain enzymes)

** Cells without nucleus eg red blood cells have a short life span

** Animal cells got many small vacuoles. Plant cells got 1 big vacuole ** Plant cells have NO centrioles ** Golgi Apparatus CANNOT be seen under the light microscope

**May surround vacuoles in the cell

4) Diagram of a general animal cell