Module 2 - All cells arise from other cells Flashcards
2 marks
Describe and explain 2 specialisations of the root hair cell that enable it to absorb water from the soil
- Many mitochondria provide ATP for active transport of mineral ions into the cell
- Root hair increase surface area for absorption
- Permanent vacuole containing sap, to store sap to keep water potential low
- Thin walls reduces diffusion distance for osmosis
2 marks
Bacteria are often used in industry as a source of enzymes. One reason is because bacteria divide rapidly, producing a large number of them in a short time.
Describe how bacteria divide.
- Binary fission
- Replication of circular DNA
- Division of cytoplasm to produce 2 daughter cells
- Each with a single copy of circular DNA
Cyclin D undergoes DNA replication faster
Some tumour cells contain higher than normal concentrations of cyclin D.
Suggest why higher than normal concentrations of cyclin D could result in a tumour.
- Shortens interphase/ DNA replication starts faster
- Uncontrolled cell division
- Resulting in a mass of abnormal cells
Explain interphase
- Increase in volume of cell
- DNA replication
- Organelles replication
- Energy stores increase (ATP, protein synthesis)
Explain prophase
- Chromosomes condense and become visible
- Nuclear envelope disappears
Explain metaphase
- Chromosomes arrange themselves at the equator of the cell
- Spindle fibres attach to centromere
Explain anaphase
- Centromeres divide
- Spindle fibres contracts/ shortens
- One of each sister chromatid pulled to poles of the cell
Explain telophase
- Chromosomes uncoil
- Spindle fibres disintegrates
- Nuclear envelope reforms
Explain cytokineses
- Cytoplasm splits
- Cell membrane forms between 2 cells
1 mark
Cells lining the human intestine complete the cell cycle in a short time. Explain the advantage of these cells completing the cell cycle in a short time
Form / replace cells quickly / rapidly / divide / multiply / replicate rapidly
