B1 cell structure and transport Flashcards
how do light microscopes work
use a beam of light to form an image
how much can light microscopes magnify
x2000
how much can school light microscopes magnify
x400
advantages light microscopes
relatively cheap, can be used anywhere and magnifies live specimens
what did electron microscope allow scientists to see and understand
more about subcellular structure inside cells
how do electron microscopes work
use a beam of electrons to form an image
how much can electron microscopes magnify up to
x 2 000 000
disadvantages of electron microscopes
large, expensive and have to be kept in special temp pressure and humidity
difference between transmission and scanning electron microscope
T - 2d images but high magnification
S- 3d images but low magnification
how to calculate image size
magnification x actual size
how to calculate magnification
image size/ actual size
OR
objective lens x eye piece lens
what does the objective lens do
magnifies object at different intensities
what does the eyepiece do
magnifies image for viewer
what does light do
provides light to view the object
what does the coarse focus do
This moves the stage by a large amount to bring the image into focus
what does the fine focus do
This moves the stage by a small amount to focus the image carefully
what is the resolution
the ability to distinguish between two separate points
what does the resolving power do
affects how much detail an image can show
the lower the resolving power…..
the higher the detail
resolving power for:
light microscope
scanning electron
transmission electron
L - 200nm
S - 10 nm
T - 0.2 nm
how many mm in a micrometre (um)
1000
how many um in a nm (nanometre)
1000
what microscope has a higher resolving power and magnification and what has this enabled scientists to do
An electron microscope has much higher magnification and resolving power than a light microscope. This means that it can be used to study cells in much finer detail. This has enabled biologists to see and understand many more sub-cellular structures.
when was the light microscope discovered
17th centurary
when was the electron microscope discovered
1930
what does the nucleus do
control all activity in the cell
what does the nucleus contain
genes on the chromosomes
what do chromosomes do
carry out instructions on making proteins to build new cells
diameter of nucleus
10um
what is the nucleus surrounded by
nuclear membrane
what is the cytoplasm and what does it do
- liquid gel where most organelles are suspended and is where most chemical reactions take place
what does the cell membrane do
controls the movement of substances in and out of the cell
what does the mitochondria do
its where aerobic respiration takes place, releasing energy for cells
what to ribosomes do
where protein synthesis takes place, making proteins for the cells that need it
what is the algae apart of
protist kingdom
what are plants and algae cells made out of
cellulose
what does cellulose do
strengthen the cell and gives it support
where is the chloroplast found and what does it contain
in all green parts of the plant, it contain chlorolphyll
what does chlorophyll do
it absorbs light hence its why its used for photosynthesis
what is the permanent vacuole
a space in the cytoplasm filled with sap
why is the permanent vacuole important to plants
its keeps the cell rigid, supporting the plant
what do plant cells contain
mitochondria, cytoplasm, cell wall, nucleus, permanent vacuole, ribosomes, cell membrane and chloroplast
what do animals cells contain
mitochondria, cytoplasm, ribosomes, nucleus, and cell membrane
what do all eukaryotic cells contain
cytoplasm, cell membrane, genetic material and an enclosed nucleus
what is genetic material known as
DNA