12.5 meiosis

0.0(0)
Studied by 0 people
call kaiCall Kai
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
GameKnowt Play
Card Sorting

1/3

encourage image

There's no tags or description

Looks like no tags are added yet.

Last updated 10:30 AM on 6/1/26
Name
Mastery
Learn
Test
Matching
Spaced
Call with Kai

No analytics yet

Send a link to your students to track their progress

4 Terms

1
New cards

describe meiosis and uses

  • chromosomes is reduced to diploid (2n) to haploid (n) - product is a gamete due to fertilisation

  • ensures chromosome number of individuals remains the same

  • 2 division of chromosomes to make 4 daughter cells that arent genetically identical

2
New cards

meiosis I

prophase I: Chromosomes condense into two sister chromatids joined by a centromere.
Homologous chromosomes pair to form bivalents.
Crossing over occurs at chiasmata between maternal and paternal chromosomes.
Spindle forms, centrioles move to poles, and nuclear membrane breaks down.

meta I: Bivalents line up at the equator and attach to spindle fibres.
Orientation is random → independent (random) assortment.

ana I: Homologous chromosomes are pulled to opposite poles.
Each chromosome still has two chromatids (genetically different due to crossing over).

telo I: Chromosomes reach poles, nuclear membranes reform.
Each nucleus is haploid (one chromosome from each pair).

cytokinesis: cell divides to two haploid cells

<p>prophase I: <span>Chromosomes condense into </span><strong><span>two sister chromatids</span></strong><span> joined by a centromere.</span><span><br></span><strong><span>Homologous chromosomes pair</span></strong><span> to form </span><strong><span>bivalents</span></strong><span>.</span><span><br></span><strong><span>Crossing over</span></strong><span> occurs at </span><strong><span>chiasmata</span></strong><span> between maternal and paternal chromosomes.</span><span><br></span><span>Spindle forms, </span><strong><span>centrioles move to poles</span></strong><span>, and </span><strong><span>nuclear membrane breaks down</span></strong><span>.</span></p><p><span>meta I: Bivalents line up at the </span><strong><span>equator</span></strong><span> and attach to spindle fibres.</span><span><br></span><span>Orientation is </span><strong><span>random</span></strong><span> → </span><strong><span>independent (random) assortment</span></strong><span>.</span></p><p><span>ana I: Homologous chromosomes are </span><strong><span>pulled to opposite poles</span></strong><span>.</span><span><br></span><span>Each chromosome still has </span><strong><span>two chromatids</span></strong><span> (genetically different due to crossing over).</span></p><p><span>telo I: Chromosomes reach poles, </span><strong><span>nuclear membranes reform</span></strong><span>.</span><span><br></span><span>Each nucleus is </span><strong><span>haploid</span></strong><span> (one chromosome from each pair).</span></p><p><span>cytokinesis: cell divides to two haploid cells</span></p>
3
New cards

meiosis II

pro II Chromosomes condense into two chromatids joined by a centromere.
Spindle forms and nuclear membrane breaks down.

meta II Chromosomes line up at the equator and attach to spindle fibres.
Chromatids may orientate randomly → contributes to variation

ana II Centromeres divide and chromatids are pulled to opposite poles.
Chromatids are now called chromosomes

telo II Chromosomes reach poles and nuclear membranes reform

Cytokinesis Cells divide to form four genetically different haploid cells

4
New cards

compare meiosis and mitosis

Mitosis takes place in one division, meiosishas two consecutive divisions.

Mitosis produces two genetically identical cells, as identical sister chromatids are separated. Meiosis produces four cells that are not genetically identical because of crossing over in prophase I and random assortment in metaphase I and II.

Meiosis can only happen in diploid cells as the homologous pairs form bivalents in prophase I. The diploid number is reduced to the haploid number. Mitosis can happen in diploid or haploid cells as the sister chromatids from each chromosome are separated into new cells. Haploid cells undergoing mitosis produce haploid cells, diploid cells undergoing mitosis produce diploid cells.