Biology Topic 1

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  • Created by: Hannah
  • Created on: 12-10-12 18:41

Bacteria cell structure diagram (http://www.bbc.co.uk/schools/gcsebitesize/science/images/add_edex_bio_bacteria.jpg)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)

Cytoplasm is where the chemical reactions take place and is found in an animal, plant and bacterial cell. The cell membrane controls the movements of chemicals in and out of the cells and is found in the plant and animal cell. The nucleus contains chromosomes which carry genes that controls the activies of the cells- found in the animal and plant cells. Mitochondria is where the sugar is broken down  by respiration releasing energy and is found in animal and plant cells. The Cell way consist of a jelly like substances that gives the cells it shape. It is made out of celloluse, strengthen the wall  and lets water and other chemicals pass through. It is found in both Plant and Bacterial cells.

The vacoule is a large fluid filled in the space of the cytoplasm, keeping the cell turgid. Turgid means being enlarged and swollen with water. It is just found in the plant cell. Chloroplast contains chlorophyll which is used in photosynthesis and is in plant cells. Plasmid DNA is loops of DNA/chromosal that are found loose in the cytoplasm and is found in the bacteria. They control the cells activities and replication. The flagellium propels the cell through liquids by rotating and is part of the bacteral cells only.

Jorissen created a microscope where the objects near the centre of the tubes looked enlarged, much more longer than any other magnifying glass. They invented the compound microscope, but because of the poor quality of the lenses, it could only magnified objects to 20X or 30X it's normal size.

Anthony used a smaller lense and made it curvatures. He saw that the rounder the lens is; it produces a greater magnification and could magnified u to 270X. He improved the design and capability of microscopes. He coined the term 'cell' when looking at a piece of cork under a 30X magnification as it looked like the cells in a prison.

Resolving power/Resolution refers to how well a microscope from an image of a cell so that we can distinguish it's different components from one another. The greater the resolving power; the better clarification. Resolving power is the measure of the quality of a light microscope.

Light microscopes are limited by their resolution  as they cannot produce clear images of objects than 0.2 micrometeres. The Electron microscope was invented in the 1930's by Max Knolt and Ernest Ruska. Electron microscopes use beams of electrons rather than light to produce images. They can view objects as small as diameters of an atom.

Transmission electron microscope (TEMs) pass a beam of electron through a thin speciman. Scanning electron microscope (SEMs) scan a beam of electrons over the surface of the specimens. Specimens of an electron microscope must be preserved and dehydrated so living cells cannot be viewed.

Light source- could be a mirror, but most likely a bulb built into the base.

Diaphragm- adjusts the amount of light striking an object. Oscular lens (eye piece)- magnifies objects and focuses lgiht tou your eyes…

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