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  • Created by: callum
  • Created on: 31-03-12 13:36

Prokaryotic cells

the two basic types of cells are Prokaryotic and Eukaryotic cells

The prokaryotic kingdom consists of bacteria and cyanobacteria

Prokaryotic cells have no nuclei or any other membrane-bound cell organelles.

most prokaryotic cells are extremely small and their DNA is not associated with anyproteins and lies free in the cytoplasm.

A cell wall is always present in a prokaryotic cell.

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Eukaryotic cells

all other living organisms ( not bacteria or cyanobacteria ) have cells that contain membrane bound organelles such as nuclei and mitochondria.

These are called Eukaryotic cells .

Eukaryotic cells are larger than prokaryotic cells.

not all Eukaryotic cells have cell walls.

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parts of the Eukaryotic cell

Mitochondria: these are the site of the later stages of aerobic respiration

nucleus: contains chromosomes and a nucleolus. the DNA in the chromosomes contain the instructions for protein synthesis.

nucleolus: dense body within the nucleus where ribosomes are made.

Rough endoplasmic reticulum (rer): system of interconnected , membrane bound flattened sacs which attach to ribosomes where proteins made by the ribosomes are transported through the ER to other parts of the cell.

Ribosomes: made of RNA and protein, these small organelles are found free in the cytoplasm or attached to the endoplasmic reticulum . these are the site of protein synthesis.

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parts of the Eukaryotic cell (2)

cell surface membrane: Phospholipid bilayer containing proteins and other molecules forming a partially permeable barrier

Smooth Endoplasmic reticulum (ser): like rough ER, but does not have any attached ribosomes . Smooth ER makes lipid and steroids (e.g. reproductive hormones)

Golgi apparatus: stacks of membrane-bound sacs formed by fusion of vesicles from the ER. modifies proteins and packages them in vesicles for transport.

Lysosome: round sacs containing digestive enzymes and bound by a single membrane. Involved in the breakdown of unwanted structures within the cells when old cells are to be replaced or being developed. The Acrosome is a specialised lysosome.

Centrioles: every animal cell has one pair of centrioles, which are hollow cylinders made up of a ring of nine protein microtubules. they are involved in the formation of the spindle during nuclear division and in transport within the cell cytoplasm.

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