Cellular Organisation and Function

This section looks at the cell as the basic unit from which most living organisms are constructed. The pats of a cell are identified and their functions considered. Differences between plant and animal cells performing different functins within a plant or animal are discussed. The particular role of the cell membrane in the uptake or loss of water is examined.

All living organisms are made up of cells

Know the diagram of both plant and animal cell, as well as labelling

(editors note: will add pictures of above at a later date)

Differences between plant and animal cells:

Plant Cell Wall	Animal no cell wall
Permanant vacuole	temp. vacuole
chloroplast	no chloroplast
starch grains	glycogen granules
regular shape	irregular shape

Definitions

Nucleus

• controls chemical reactiosn
• contains information to make living organism
• tells cell what to do

Cytoplasm

• where chemical reactions take place

Cell Membrane

• controls what comes in and goes out of cell

Cell Wall

• made of cellulose
• gives cell strength and support

Vacuole

• contains salt and suger solution, called cell sap
• supports cell

Chloroplast

• contains chlorophyll
• for photosynthesis

Mitochondria

• release engery by cellular respiration

A group of specialised cells working together are called tissue

Osmosis and Diffusion

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration., until equilibrium is reached.

• Larger Molecules - slower rate of diffusion

Osmosis is the movememtn of water molecules from an are of high concentration (weak solution) to an area of low concentration (strong solution), though a partially permeable membrane, until equilibrium is reached.

• when plant cell vacuoles swell up, cells become turgid
• when lacking water, the plant wilts, and the cells become flacid
• when lots of water leaves, cytoplasm comes away from cell wall, this is called plasmolysis.

 

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