Meiosis Flashcards
How many sets of genes are found in most adult organisms?
2 complete sets of genes, one set from each parent
where are genes located?
on the chromosomes
homologous?
chromosomes are in corresponding pairs from each parent (like a pair of shoes for a right and left foot)
diploid?
a cell with homologous chromosomes and therefore, homologous genes (we have 13 pairs of homologous chromosomes and a total of 26 chromosomes in every cell.) All our cells are diploids except the egg and sperm cells.
haploid?
having only a single set of chromosomes ( like and egg or a sperm cell)
the process in which a diploid becomes a haploid is called?
meiosis, 1 diploid becomes 4 haploids.
how many divisions are in meiosis?
Two. meiosis I and meiosis II
What happens in meiosis I?
2 daughter cells are produced BUT they don’t contain the same exact chromosomes as the parent cell because of the cross over process among the homologous chromosomes during prophase. The left and right shows swap some info during prophase I. New combos of alleles form.
What happens in meiosis II?
No more chromosomal replication. Yet there is still cell division, ending with 4 cells with half the chromosomes of the original cell. These cells will develop into gametes (sperm and eggs)
what is a tetrad?
it contains 4 chromatids and occurs during meiosis prophase I. Super important time: its where the chromosomal pairs cross-over and exchange some genetic material so that we don’t have an opportunity to be a clone of one of our parents.
Whats the big difference between meiosis and mitosis?
mitosis - creates 2 genetically identical diploid cells, with no change in chromosomal #. meiosis - creates 4 genetically different haploid cells, with half the # of chromosomes.
Whats similar between mitosis and meiosis?
Both ensure cells inherit genetic material. Both have an interphase where genetic material is replicated. But - the chromosomes are separated differently during prophase I.
