Detach the first section including exam questions and put your name on it Homework for MONDAY Complete the section on Methods of studying cells INCLUDING exam questions to hand in on MONDAY ID: 1042303
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1. Hand in your homework please!Detach the first section (including exam questions) and put your name on it!Homework for MONDAY: Complete the section on ‘Methods of studying cells’ INCLUDING exam questions to hand in on MONDAY.
2. The Cell Cycle and Mitosis
3. Cell DivisionMitosis is a type of cell division that produces genetically identical copies of cells.Not all cells can divide.What types of cells DO divide?Cells that can divide go through a CELL CYCLE.
4. The Cell CycleMitosis is only a small part of the ‘life’ of a cell. The process from one cell division to the next is known as the cell cycle.There are 4 parts to the cell cycle: Gap 1 Synthesis Gap 2 MitosisThese stages are all parts of interphase.
5. The cell cycle
6. Can you think of 3 reasons why mitosis is important?
7. A bit of background…A chromosome is a strand of DNA.After S-phase (DNA replication), identical copies of chromosomes remain attached – SISTER CHROMATIDS joined at the CENTROMERE.DNA replicationChromosomeSister chromatidsCentromere
8. The chromosomes can’t be seen most of the time – they are tangled strands of DNA.During cell division, the chromosomes condense – they coil up, aided by a number of proteins.Reminder:
9. Mitosis
10. InterphaseThe cell is engaged in metabolic activity in preparation for mitosis Chromosomes are not visible under the light microscope
11. ProphaseChromosomes condense and become visible under the light microscopeThe nucleolus disappearsCentrioles begin moving to opposite ends of the cell and spindle fibres extend from the centrioles
12. MetaphaseThe nuclear membrane dissolves, marking the beginning of metaphase. Spindle fibres attach to the centromere of each chromosome.
13. MetaphaseSpindle fibres align the chromosomes along the equator of the cell This helps ensure that during the next phase, when the chromosomes are separated, each new nucleus will receive one copy of each chromosome
14. AnaphaseThe sister chromatids separate at the centromeres and move to opposite sides (poles) of the cell
15. TelophaseChromatids arrive at opposite poles of the cell, and nuclear membranes form around themThe chromosomes are no longer visible under the light microscope
16. Another way to remember the stages…InvisiblePresentMiddleApartTwo
17. CYTOKINESISThe cytoplasm divides so two cells are formed.The two daughter cells are genetically identical to each other, and to the parent cell.
18. Try to identify the stages of mitosis in the two photomicrographs on the back of your sheet.Write a sentence for each one to explain how you reached your answer.
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20. Stages of the cell cycle