Biology GCSE AQA Grade 9 Unit 1: Cell Biology notes made by Grade 9 student, now studying A level Biology. Includes all relevant details adhering to the specification and visual aids, such as diagrams, pictures, coloured notes, etc.. Similar quality notes available for all units for each triple sci...
Cells have structures inside them called sub-cellular structures. (organelles)
In animal cells these include:
- Nucleus: controls the activities of the cell and contains the genetic material
- Cytoplasm: where most of the chemical reactions take place
- Cell membrane: controls the passage of substances into and out of the cell
- Mitochondria: where aerobic respiration takes place
- Ribosomes: where proteins are synthesised
Plant cells and algal cells contain all sub-cellular structures found in animal cells.
They also have:
- Cell walls: made from cellulose, these strengthen the cell and help to retain its
structure.
- Permanent vacuoles: filled with cell sap, which supports the plant.
Plants need to make their own food, so some contain chloroplasts.
Chloroplasts absorb light to make glucose (food) by photosynthesis.
- Not all plant cells have them, e.g. root cells because they don’t receive light.
Vacuole
Cell wall
Cell membrane
Ribosome
Chloroplast
Ribosome
Nucleus
, Prokaryotic and Eukaryotic Cells
PROKARYOTIC EUKARYOTIC
Much smaller in size Plant, animal and fungal cells
Genetic material is a single DNA loop Genetic material (DNA) is enclosed in a
May be 1+ small rings of DNA (plasmids) nucleus
No mitochondria or chloroplasts Much larger
e.g. bacterial cells and archaea Membrane-bound organelles
PROKARYOTIC EUKAROTIC
Evolved
Oldest cell type
Have DNA
Organelles
Small and Have ribosomes
simple
No nucleus or Have cytoplasm Larger and
organelles more complex
Have a plasma
membrane Nucleus
Unicellular
Unicellular/
multicellular
BOTH
A Typical Bacterial Cell
They have many different shapes.
Are prokaryotic cells.
The roles of mitochondria and chloroplasts are adopted by the cytoplasm.
Plasmids are present (circles of DNA that can be transferred between cells).
- Allow bacterial cells to move genes between cells.
- Are very useful.
- Allow genes to be inserted into bacteria in genetic engineering.
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