meiosis Flashcards
what does meiosis produce?
four genetically different haploid daughter cells.
do these cells have a full number of chromosomes or half the number of chromosomes?
they each have half the number of chromosomes.
where does meiosis occur?
only happens in gamete-producing cells.
how many chromosomes does each cell have?
23.
how many sets of chromosomes do each cell have?
they each have 1 set.
what are some differences between meiosis and mitosis?
- meiosis produces four daughter cells, mitosis produces only two
- meiosis produces genetically different cells, mitosis produces genetically identical cells to each other and the parent cell.
- meiosis produces haploid cells, mitosis produces diploid cells.
- meiosis occurs in gamete-producing cells (ovaries and testes), mitosis occurs in body cells.
what happens before the cell begins to divide?
it duplicates its DNA, one arm of each x-shaped chromosome is an exact copy of the other arm.
how many divisions are there in meiosis?
there are 2 divisions.
what happens during the first stage of the first division?
the chromosomes line up in the centre of the cell, one from the mother and one from the father.
what happens during the second stage of the first division?
the pairs are then pulled apart so each new cell has only one copy of each chromosome.
what is the result at the end of the first division?
each cell will now have a mixture of the mothers and father chromosomes - this creates genetic variation in offspring.
what happens in the second division?
the chromosomes line up in the centre of the cell AGAIN, the arms of the chromosomes are then pulled apart.
what is the result at the end of both divisions?
four haploid daughter cells - these are gametes.
what does each gamete contain?
each gamete only has a single set of chromosomes.
