AQA Biology IGCSE Chapter 1

Seite 1

Parts of an animal cell and it's functions:-

Nucleus- Controls the cell's activities

Cell Surface Membrane- controls the movement of substances in and out of the cell.

Cytoplasm- Where all the chemical reactions take place.

Mitochondria- where energy is released during respiration

Ribosomes- where protein synthesis takes place

Other Parts of a plant cell

Chloroplasts- contain chlophyll that absorb light energy for photosynthesis

Cell wall- made out of cellulose and helps the cell for support

Large storage vacuole- contains cell sap which help keep the cell turgid

Bacteria

Are very small and can only be seen through a microscope

They don't have a nucleus but genetic material is found in the nucleus as a long strand of DNA

Some genes are located in circular structures called PLASMIDS

Yeast

they are single celled organisms

they have a nucleus, cytoplasm, cell wall and a cell membrane.

can be used to make antibiotics and ethanol

uses anaerobic respiration (fermentation) so can live with very little oxygen.

Specialised cells

Specialised cells are special as they carry out a particular function

Some specialised cells include, root hair cell, muscle cells, sperm cells, cone cells and fat cells.

Cells maybe are specialised to work as tissues, organs or whole organisms.

The structure of these cells are sometimes linked to their functions. E.g- if a cells needs a lot of energy it will have a lot of mitochondria like sperm or muscle cells

Diffusion

The net movement of particles from an area of high concentration to an area of low concentration down the concentration gradient

Concentration gradient is the difference between two areas. The larger the difference, the faster the rate of diffusion

Examples of Diffusion:- of oxygen and glucose for respiration through blood streams, gas exchanges in the alveoli between Carbon Dioxide and oxygen.

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