B1- Cell Biology
chromosomes and mitosis
cells
diffusion
cell differentiation and specialisation
osmosis
stem cells
microscopy
active transport
exchange surfaces
exchanging substances
cells are studied using microscopes
organisms can be prokaryotic or eukaryotic
all living things are made of cells
eukaryotic cells are complex and include all animal and plant cells
prokaryotic cells are smaller and simpler and include bacteria
Plant and animal cells have similarities and differences
differences
Rigid cell wall
permanent vacuole
chloroplasts
made of cellulose, it supports the cell and strengthens it
Similarities
contains cell sap, a weak solution of sugar and salts
these are where photosynthesis occurs, which makes food for the plant. they contain a green substance called chlorophyll, which absorbs the light needed for photosynthesis.
cytoplasm
cell membrane
nucleus
contains genetic material for the that controls the activities of the cell
gel-like substance where most of the chemical reactions happen,it contains enzymes that control these chemical reactions
holds the cell together and controls what goes in and out
mitochondria
these are where most of the reactions for aerobic respiration take place, respiration transfers energy that the cell needs to work.
ribosomes
these are where proteins are made in the cell
Bacteria cells
Bacteria are prokaryotes
microscopes let us see things that we can't see with the naked eye. the microscopy techniques we can use have developed over the years as technology and knowledge have improved.
light microscopes use light and lenses to form an image of a specimen and magnify it
they also have a higher resolution
electron microscopes use microscopes instead of light to form an image . they have a much higher magnification than light microscopes.
electron microscopes let us see much smaller things in more detail like the internal structure of mitochondria or chloroplasts they even let us see much smaller things like ribosomes
magnification formula
magnification= image size / real size
the practical
1) add a drop of water onto a clean slide
2) cut up an onion and separate it out into the layers. use tweezers to peel off some epidermal tissue from the bottom of one of the layers
3) using the tweezers place the epidermal tissue into the water on the slide
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