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Topic B1: Cell level systems
B1.1 Cell structures
Demonstrate an understanding of number, size and scale and the quantitative relationship
between units.
Use estimations and explain when they should be used.
Calculate with numbers written in standard form.
Describe how light microscopes and staining can be used to view cells.
Explain how the main subcellular structures of eukaryotic (plants and animals) and
prokaryotic cells are related to their functions.
Explain how electron microscopy has increased our understanding of subcellular structures.
Eukaryotes;​ (all animals and plants) are made from complex cells and a nucleus that contains the
genetic material. They size from 10-100վm.
Prokaryotes;​ (bacterial cells) are made from simple cells and no nucleus with free genetic material.
They size from 1-10վm. (1վ=1000mm)
Bacteria ​are unicellular. They perform and carry out all the seven life processes (Mrs. Gren). Some
examples of bacteria would be:
- Streptococcus
- Streptomyces
- E. coli
Nucleus: ​controls the cell and contains genetic material.
Chloroplasts:​ contain chlorophyll and trap light energy to store for photosynthesis.
Cell wall:​ supports the cell, made out of cellulose in plants and peptidoglycan in animal cells.
Vacuole: ​contains cell sap and helps to support the cell.
Free genetic material: ​contains one circular strand of DNA, found in the cytoplasm and contains
Flagella: ​allow the cell to move.
Pili:​ allows cells to attach to surfaces; transfer genetic material.
Slime capsule: protects cell and helps it to stick to smooth surfaces.
Mitochondria:​ contains enzymes for respiration, site of respiration.
Cell membrane:​ contains receptor molecules and controls and foresees what enters and leaves the cell,
provides a selective barrier.
Cytoplasm: ​site of chemical reactions.
Plasmid: ​circular DNA stores extra genes.