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All living cells are made up of one cell (unicellular) or more cells (multicellular).

Metabolic processes take place within cells.

New cells are derived from existing ones.

Cells posses the genetic material of an organism which is passed from one parent cell to the
daughter cells.


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The eyepiece lenses further magnify the image produced by the objective.

Animal cell

Cell surface membrane a thin protein and phospholipids bilayer that controls the movement of
materials in and out of the cell.

Cytoplasm watery material with a jellylike consistency.

Nucleus made up of jellylike nucleoplasm, the nucleolus and…

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Developed because light microscope has poor resolving power.

Uses beam of electrons.

Short wavelength and therefore could resolve objects well it had high resolving power.

As the electrons are negatively charged the beam could be focused using electromagnets.

Two types of electron microscope. Transmission Electron Microscope (TEM) Scanning Electron

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Gives a 3d image by computer analysis. Resolving power is less than the TEM.

Environmental scanning electron microscope

One major disadvantage of electron microscopes is that the removal of water from the
specimen during its preparation and the vacuum in which it is observed prevent the specimen
being observed in…

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Nucleolus is a small spherical body within the nucleoplasm. It manufactures ribosomal RNA
and assembles ribosomes.

The functions of the nucleus are to:

act as the control centre of the cell through the production of mRNA and protein synthesis.

retain the genetic material of the cell in the form of…

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stalked (elementary) particles that are about 4nm high.

The stalked particles contain enzymes involved in the synthesis of ATP.

matrix makes up the remainder of the mitochondrion. It is a semirigid material containing
protein, lipids, and traces of DNA that allow them to control production of their own proteins. The…

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80s type, found in eukaryotic cells, is around 25nm in diameter.

70s type, found in prokaryotic cells, slightly smaller.

Each ribosome has two subunits one large and one small each contains ribosomal RNA and
protein. There's loads of them, account for 25% of a dried cell.

Important for protein synthesis.…

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enzymes such as proteases and lipases. Up to 50 such enzymes may be contained in a single

Up to 1 micrometer in diameter, lysosomes isolate these potentially harmful enzymes from the
rest of the cell, before releasing them, either to the outside or into a phogcytic vesicle within the…

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Threads that extend from the cell surface. Only a few types of cells posses it. Produce wave like
motion across the surface of the cell.


moves an entire organism, e.g. cillia on the surface of the protocist propel it through the water.

to move material within an organism,…

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Bacteria occur in every habitat in the world. They are versatile, adaptable and successful, much
of their success is a result of their small size, normally in the range of 0.110 micrometers in

Their cellular structure is relatively simple. All bacteria posses a cell wall which is made up…


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