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different numbers of plasmids

Host Cell Replication
Viruses use attachment proteins to bind to complementary receptor
proteins
Different receptor proteins used depending on host cell
Viruses own DNA/RNA is injected into host mimicking a hijack
Using the host, viral molecules are able to replicate

Analysing Cell Components
Magnification
How big the image is compared to the specimen itself

Topic 2A- Cell Structure and Division

6

Resolution
Image quality

Optical Microscopes
Uses light to create image
Unable to view organelles smaller than 0
...
5k

Electron Microscopes
Electrons used for image
Higher resolution= More detailed image
Max resolution of 0
...
5mil
Scanning Microscopes/ TEMS
Uses electromagnets to transmit electrons through specimen
Denser areas absorbs more electrons, darker imagery
High resolution pics
Only works on thin specimens
Transmission Microscopes/ SEMS
Scans electron beam across specimen to form image
Shows specimen surface in 3D
Can be used on thick specimens
Lower quality images

Topic 2A- Cell Structure and Division

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Cell Division: Mitosis
Parent cell dividing two genetically identical cells
Required in multicellular organism growth
Repairs damaged tissue

Mitosis Division Stages
Prophase
Chromosomes condense
Centrioles move to opposite sides of cell, forming spindle fibres
Nuclear envelope breaks down
Metaphase
Chromosomes become aligned in the centre and attach to spindle
Anaphase
Centromeres divide and separate chromatid pairs
Spindles contract, pulls chromatids to opposite ends of spindle
Telophase
Chromatids reach opposite sides of spindle
Strand uncoils and become chromosomes
Nuclear envelope forms around chromosome groups
Cytoplasm divides each containing daughter cells

Cancer- Uncontrolled Cell Division
Mitosis in controlled by genes
Uncontrolled cell division forms a tumour
Tumour invades surrounding tissue

Topic 2A- Cell Structure and Division

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Cancer Treatment
G1
Chemotherapy drugs prevents enzyme synthesis
Prevents synthesis phase and forces cell to kill itself
S Phase
Radiation usage can damage DNA
If damage is severe enough, cell kills itself preventing tumour growth

Topic 2A- Cell Structure and Division

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