This word document summarises B1-Cells and Organisation from the Kerboodle Combined Science Biology. It outlines all the important points you need to pass your GCSE.
B1- Cells and Organisation
20 January 2021
17:54
Microscopes
Microscopes let us see things we can't see with a naked eye.
There are 2 different Microscopes:
-Light Microscope
Light Microscopes uses light and lenses to form an image of a
specimen and magnify it. They let us see individual cells and large
subcellular structures like the nuclei.
-Electron Microscopes
Electron Microscopes uses electrons instead of light to form and
image. They have a higher resolution and magnification than a Light
Microscope. Electron Microscope let us see much smaller things in
more detail, like the internal structure of mitochondria and
chloroplasts and even ribosomes.
Resolution- is the ability to distinguish between 2 points, so the
higher resolution gives a sharper image.
Practical Of Microscopes (Onion Cell)
1. Add a drop of water onto the slide
2. Cut up an Onion and separate it out into layers. Use
tweezers to peal off some epidermal tissue from the
bottom and put it on the slide.
3. Add a drop of iodine solution. Iodine Solution is a stain.
Stain- Used to highlight object in a cell by adding colour to them
4. Place a cover slip ( a square of thin, transparent
plastic/glass) on to.
Use the light microscope to look at your side
1. Clip the slide onto the stage.
2. Select the lowest-powered objective lens (the one that
produces the lowest magnification)
3. Use the coarse adjustments knob to move the stage up to
just below the objective lens
4. Look at the eyepiece. Use the coarse adjustment knob to
move the stage downwards until it focuses.
, 5. Adjust the focus with the adjustment knob, until you et a
clear image.
6. If you need to see more clearly with a greater
magnification, swap to a higher-powered objective lens.
Cells
Organism can be Prokaryotes and Eukaryotes.
Eukaryotes- Organisms that are made of eukaryotic
cells
Prokaryotes- A Prokaryotic cell
Eukaryotic Cells all contain a cell membrane,
cytoplasm, and genetic material that is enclosed in a
Nucleus. An example is Animal and Plant Cells
Prokaryotic Cells consist of cytoplasm and a cell wall.
The genetic material is not in a distinct nucleus. It
forms a single DNA loop. An example is all Bacteria
Cells
Animal Cell
Nucleus- Controls genetic material that controls
activities of all the cell.
Cytoplasm- Where chemical reactions take place. It
contain enzymes that controls the chemical reactions.
Cell Membrane- Holds the cell together and controls
what goes in and out.
Mitochondria- where aerobic respiration takes place.
Respiration transfers energy that the cell needs to
work.
Ribosomes- Where proteins are made.
Plant Cell
A plant cell has all the bits the animal cell has but a few more
that animal cells don't have.
Cell Wall- made of cellulose. It supports the cell and
strengthens it.
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