Explain different stages of mitosis and meiosis.
Answers
Answered by
7
Heya Mate !!!
Here's Your Answer :-
================
Stages of Mitosis ;-
================
Mitosis is the process of cell division that forms two genetically identical nuclei from on parent cell nucleus. It is used for:
Asexual reproduction (e.g. Paramecium)
Growth (increasing cell number)
Repair and Maintenance (replace damaged cells with identical replacements)
Although we traditionally break down mitosis into a series of stages and sub-stages, it is actually a continuous process. In the micrographs opposite, you can see that mitosis is not necessarily synchronised and looks much messier than the clean, idealised textbook diagrams!
Interphase - Not strictly a stage of mitosis, this is where the cell prepares to divide by growing, storing energy, replicating organelles and replicating DNA
Prophase - The chromosomes supercoil and become visible under a light microscope. The chromosomes assume their classic 'X' shape - two sister chromatids joined in the middle at the centromere. Other key events are:
Nuclear Envelope breaks down;
Centriole divides in two, travels to opposite poles of the cell to form the spindle.
Metaphase - An easy stage to identify, Metaphase is characterised by the chromosomes lining up, single file, along the middle (the equator) of the cell. At this point, each chromosome becomes attached to the spindle at its' centromere.
Anaphase - Another easily recognisable stage! Anaphase sees the chromosomes split at the centromere, separating the sister chromatids:
The sister chromatids are pulled apart to opposite poles of the cell
At this point, each chromatid becomes an individual chromosome - identical to the original parent chromosome
Spindle fibres shorten, pulling each chromatid by the centromere - this causes the chromatids to look like Vs
Telophase - a simple stage to recognise - you will see two nuclei starting to form in early telophase; in late telophase you will no longer be able to see the chromosomes, just two complete nuclei at opposite ends of the cell.
=================
Stages of Meiosis ;-
=================
Human body cells have 46 chromosomes. These are arranged in pairs, with one copy of each chromosome from Mum, and the other from Dad. If your sperm and eggs were made using mitosis, when these two cells fused at fertilisation, the egg would have 96 chromosomes. Definitely not human!
Meiosis is the process of cell division that halves the chromosome number and makes gametes (human gametes contain 23 chromosomes). This ensures that at fertilisation the number of chromosomes found in normal body cells - the diploid number - is restored.
Meiosis involves two divisions of the nucleus:
The first division generates most of the variation
The second division halves the chromosome number.
Meiosis is a very technical process that is most easily described in diagrams and tables (see above and below).
< Hope It Helps >
Here's Your Answer :-
================
Stages of Mitosis ;-
================
Mitosis is the process of cell division that forms two genetically identical nuclei from on parent cell nucleus. It is used for:
Asexual reproduction (e.g. Paramecium)
Growth (increasing cell number)
Repair and Maintenance (replace damaged cells with identical replacements)
Although we traditionally break down mitosis into a series of stages and sub-stages, it is actually a continuous process. In the micrographs opposite, you can see that mitosis is not necessarily synchronised and looks much messier than the clean, idealised textbook diagrams!
Interphase - Not strictly a stage of mitosis, this is where the cell prepares to divide by growing, storing energy, replicating organelles and replicating DNA
Prophase - The chromosomes supercoil and become visible under a light microscope. The chromosomes assume their classic 'X' shape - two sister chromatids joined in the middle at the centromere. Other key events are:
Nuclear Envelope breaks down;
Centriole divides in two, travels to opposite poles of the cell to form the spindle.
Metaphase - An easy stage to identify, Metaphase is characterised by the chromosomes lining up, single file, along the middle (the equator) of the cell. At this point, each chromosome becomes attached to the spindle at its' centromere.
Anaphase - Another easily recognisable stage! Anaphase sees the chromosomes split at the centromere, separating the sister chromatids:
The sister chromatids are pulled apart to opposite poles of the cell
At this point, each chromatid becomes an individual chromosome - identical to the original parent chromosome
Spindle fibres shorten, pulling each chromatid by the centromere - this causes the chromatids to look like Vs
Telophase - a simple stage to recognise - you will see two nuclei starting to form in early telophase; in late telophase you will no longer be able to see the chromosomes, just two complete nuclei at opposite ends of the cell.
=================
Stages of Meiosis ;-
=================
Human body cells have 46 chromosomes. These are arranged in pairs, with one copy of each chromosome from Mum, and the other from Dad. If your sperm and eggs were made using mitosis, when these two cells fused at fertilisation, the egg would have 96 chromosomes. Definitely not human!
Meiosis is the process of cell division that halves the chromosome number and makes gametes (human gametes contain 23 chromosomes). This ensures that at fertilisation the number of chromosomes found in normal body cells - the diploid number - is restored.
Meiosis involves two divisions of the nucleus:
The first division generates most of the variation
The second division halves the chromosome number.
Meiosis is a very technical process that is most easily described in diagrams and tables (see above and below).
< Hope It Helps >
Similar questions