AQA Biology IGCSE Chapter 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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