2.2 Cell Division Flashcards
In multicelluar organisms, can specialised cells divide
No
What cells cannot divide
Specialised cells
What occurs during G1 phase of the cell cycle
- Growth as cell increases in size
- New organelles made
What occurs during S phase of the cell cycle
- DNA replication
- Chromatids produced
- Chromatids join at centromere to form a chromosome
What occurs during the G2 phase of the cell cycle
- Growth as cell increases in size
- New organelles made
What happens during the M phase of the cell cycle
Mitosis + Cytokenisis
Describe what occurs in prophase of mitosis
- DNA coils and condenses to form visible chromosomes
- They are two sister chromatids joined at the centromere
- Spindle fibres begin to form
Describe what occurs during metaphase of mitosis
- Chromosomes line up at the equator of the cell
- Spindle fibres attach to centromere
Describe what occurs during anaphase of mitosis
- Chromosomes are pulled apart
- Centromere splits
- A chromatid from each pair is** pulled to opposite poles** of the cell
- As spindle fibres contract and shortern
Describe what occurs during telophase of mitosis
- Chromosomes uncoil and uncondense
- Two diploid nuclei form at cell poles
- Spindle fibres break down
Describe the process of cytokenisis in mitosis
- Cytoplasm divides
- 2 genetically identical daughter cells form
What is the difference in the process of cancer cells dividing, and regualr cells dividing
Mitosis is a controlled process
What ensures that DNA has been copied correctly during the cell cycle, and what happens if this fails
- Checks occur
- If they fail, uncontrolled cell division occurs
- Uncontrolled cell division can lead to tumours and cancer
How to cancer treatments work
Slow the rate of cell division, or destroy rapidly dividing cells
Describe the process of binary fission
- Circular DNA and plasmids are copied
- Cytoplasm divides
- 2 daughter cells are produced
- Each with a single copy of DNA and plasmids
Why don’t viruses undergo cell division
They are non-living
Describe the process of viral replication
- Attachement proteins on virus attach to cell receptors
- Virus injects nucleic acid into host cell
- Reverse transcriptase makes DNA from RNA
- The cell replicates the nucleic acids
- Cell produces viral proteins, capsids and enzymes
- The virus is assembled and released from the cell by budding of cell lysis
RP2: Why roots placed in warm HCl
- Break down cell walls
- Stop mitosis
RP2: Why end of root used
Where most mitosis is occuring
RP2: Why squash sample, and why not too hard
- Single layer of cells
- Allowing light’s long wavelength to pass through
- Not pushed too hard, as to not break the chromosomes
RP2: Why stain used
To distinguish chromosomes
RP2: Why differnt mitotic indices obtained from different samples
- Roots different ages
- Different species of garlic
- Different parts of root tip
- Undergo mitosis at different rates
