Biology (Cells)

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All animals and plants are made of cells. Animal cells and plant cells have features in common, such as a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes. Plant cells also have a cell wall, and often have chloroplasts and a permanent vacuole. Note that cells may be specialised to carry out a particular function.

Dissolved substances pass into and out of cells by diffusion. Water passes into and out of cells by osmosis.

Animal and Plant Cells

Function of cells which animal and plant cells have in common:

partfunction nucleus contains genetic material, which controls the activities of the cell cytoplasm most chemical processes take place here, controlled by enzymes cell membrane controls the movement of substances into and out of the cell mitochondria most energy is released by respiration here ribosomes protein synthesis happens here

Plant cells also have extra parts:

Extra Parts of Plant Cells

partfunction cell wall strengthens the cell chloroplasts contain chlorophyll, which absorbs light energy for photosynthesis permanent vacuole filled with cell sap to help keep the cell turgid

Make sure you can label diagrams of animal and plant cells, like these:

both cells have a membrane on the outside, and cytoplasm and a nucleus inside. In the plant only are the cell wall, vacuole, and chloroplast.  (http://www.bbc.co.uk/schools/gcsebitesize/science/images/aqaaddsci_06.gif)

Generalised animal and plant cell

Specialised Plant Cells

Cells may be specialised for a particular function. Their structure will allow them to carry this function out. Here are some examples:

Examples of the functions of cells:

CellFunctionAdaption cross section through a leaf cell (http://www.bbc.co.uk/schools/gcsebitesize/science/images/aqaaddsci_07.gif)

Leaf cell

Absorbs light energy for photosynthesis Packed with chloroplasts. Regular shaped, closely packed cells form a continuous layer for efficient absorption of sunlight. root hair cell - has a head and tail (http://www.bbc.co.uk/schools/gcsebitesize/science/images/aqaaddsci_08.gif)

Root hair cell

Absorbs water and mineral ions from the soil Long 'finger-like' process with very thin wall…

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