Uses a beam of light to
form a bigger (magnified)
picture of the object
Relatively cheap, can be used almost
anywhere and works on live specimen.
Electron
Invented in the 1930s
Can magnify up to x2'000'000
Uses a beam of electrons to
form a bigger (magnified)
picture of the object
Can only be used in
specific temperatures,
humidities & pressures
Transmission electron
microscopes give 2D images with
high magnification and resolution
Scanning electron microscopes
give 3D images but have lower
magnification and resolution.
Very large and expensive
Eukaryotic Cells
Animal
Nucleus
Plants
Prokaryotic Cells
Bacteria
....
Specialisation in Cells
Animals
Nerve Cells
Lots of dendrites so can connect to other nerve cells, a huge axon
that can carry the impulses, and synapses adapted to pass impulses
with chemicals and contain lots of mitochondria for energy.
Sperm Cells
Long flagellum, streamlined head with large nucleus and lots of
mitochondria and digestive enzymes in the head give the sperm
more chance of getting to the egg and passing on the genetics.
Muscle Cells
Contain special proteins, many mitochondria and store glycogen.
This means they can contract and relax, allowing us to move.
Plants
Root Hair Cells
Larger surface area, large permanent vacuole and
lots of mitochondria to speed up intake of water.
Photosynthetic Cells
Contains chloroplast and chlorophyll, positioned in continuous
layers, and have a large permanent vacuole so they can absorb
more light and photosynthesis can happen more efficiently.
Xylem Cells
...
Phloem Cells
Cell walls between cells, and the internal structure breaks down.
Companion cells with mitochondria give them energy and keep them
alive. The open tube makes it easier for the water and minerals to travel.