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The nucleus
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- Before mitosis starts, all the chromosomes in the nucleus replicate their DNA to make identical copies. The nucleus now contains two sets of replicated chromosomes, twice as many as a normal body cell.
www.bbc.co.uk/bitesize/guides/zyn9y4j/revision/3The process of mitosis - Producing new cells - National 5 ...
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Apr 24, 2022 · The Process of Semi-Conservative Replication. DNA replication occurs in preparation for mitosis, when a parent cell divides to produce two genetically identical daughter cells – as each daughter cell contains the same number of chromosomes as the parent cell, the number of DNA molecules in the parent cell must be doubled before mitosis takes ...
- Prophase. Figure 1: During prophase, the chromosomes in a cell's nucleus condense to the point that they can be viewed using a light microscope. Prophase is the first phase of mitosis.
- Prometaphase. After prophase is complete, the cell enters prometaphase. During prometaphase, the nuclear membrane disintegrates and the mitotic spindle gains access to the chromosomes.
- Metaphase. Figure 3: (a) Metaphase and (b) Anaphase. In metaphase (a), the microtubules of the spindle (white) have attached and the chromosomes have lined up on the metaphase plate.
- Anaphase. After metaphase is complete, the cell enters anaphase. During anaphase, the microtubules attached to the kinetochores contract, which pulls the sister chromatids apart and toward opposite poles of the cell (Figure 3c).
Mar 17, 2022 · The replication of DNA occurs during the synthesis phase, or S phase, of the cell cycle, before the cell enters mitosis or meiosis. The elucidation of the structure of the double helix provided a hint as to how DNA is copied.
Stage one. The DNA is unwound and unzipped. The helix structure is unwound. Special molecules break the weak hydrogen bonds between bases, which are holding the two strands together. This...
- Initiation
- Elongation
- Termination
DNA synthesis is initiated at particular points within the DNA strand known as ‘origins’, which have specific coding regions. These origins are targeted by initiator proteins, which go on to recruit more proteins that help aid the replication process, forming a replication complex around the DNA origin. Multiple origin sites exist within the DNA’s ...
Once DNA Polymerase has attached to the two unzipped strands of DNA (i.e. the template strands), it is able to start synthesising new strands of DNA to match the templates. DNA polymerase is only able to extend the primer by adding free nucleotides to the 3’ end. One of the template strands is read in a 3’ to 5’ direction, therefore the new strand ...
The process of expanding the new DNA strands continues until there is either no more DNA template strand left to replicate (i.e. at the end of the chromosome) or two replication forks meet and subsequently terminate.The meeting of two replication forks is not regulated and happens randomly along the course of the chromosome. Once DNA synthesis has ...
Jun 2, 2024 · In order for a cell to duplicate and divide into its daughter cells (either through the process of meiosis or mitosis), organelles and biomolecules must be copied first and then distributed among all cells.
Mitosis is the process by which replicated DNA is distributed to daughter cells and is itself often subdivided into five distinguishable stages: prophase, metaphase, anaphase, and telophase.
