2.2 Cells arising Flashcards
What occurs during the G1 phase of the cell cycle
Cell grows and new organelles and proteins created
What occurs during the S phase of the cell cycle
Cell replicates DNA for mitosis
What occurs during the G2 phase of the cell cycle
Cell keeps growing and proteins for mitosis created
What happens in interphase to prepare for mitosis
- Cell carries normal function
- DNA unravelled and replicated
- Organelles replicated
- ATP production increased
Prophase
- Chromosomes condense, getting shorter and fatter
- Centrioles move to opposite poles and produce spindle fibres
- Nuclear envelope breaks down
Metaphase
- Chromosomes line up at equator of cell
- Centrioles attach spindle fibres to centromere of chromosomes
Anaphase
- Centromere divides and separates sister chromatids
- Spindle fibres contract and pull chromatids to opposite poles of cell
Telophase
- Chromatids reach opposite poles. uncoil and become long and thin
- Chromosomes again - nuclear envelope reforms
- Cytokinesis
What is cytokinesis
Cytoplasm dividing
How do cancer treatments work?
Target:
- G1 = Prevent enzyme production for DNA replication - apoptosis
- S = Radiation to damage DNA to promote apoptosis
What is cancer?
- Result of uncontrolled cell division
- Tumour which invades surrounding tissue
- Tumour = excessive cells (hyperplasia)
How do tumour cells look different?
- Irregular shape
- Large and dark nucleus/ multinucleate
- Different antigens
- Divide more frequently
- Don’t produce all proteins needed
- Don’t produce adhesive material
Mitotic Index Equation
Mitotic Index = Cells with visible chromosomes / Cells observed
What are artefacts?
Objects in microscope not a part of cell/ specimen being observed
- Dust, air bubbles, fingerprints
How to prepare a cell for optical microscope
1) Clip prepared slide with specimen onto stage
2) Select lowest power objective lens
3) Coarse adjustment knob to raise stage/ slide to just below lens
4) Look down eyepiece and adjust with fine adjustment knob to get a clear image
