stages Flashcards
interphase
synthesis of proteins, organelles, ATP
DNA replication phase - S-phase
DNA present in decondensed form
prophase I
chromatin condenses into chromosomes
homologous chromosomes will pair up, we call them bivalents
homologous chromosomes exchange DNA by forming chiasma - crossing over - increases genetic variation
nuclear membrane disintegrates
centrioles move towards opposite poles
metaphase I
bivalents line up along the equatorial plane of the cells
spindle fibres attach from the centrioles to the centromere of each chromosome
anaphase I
spindle fibres contract
one chromosome from each homologous pair is pulled to opposite poles
independent assortment of chromosomes - cause of genetic variation
telophase
new nuclear envelopes are formed (phospholipid synthesis)
centrioles are replicated
chromosomes start to decondense
cytokinesis I
a cleavage furrow is formed
phospholipids are added to make new cell membrane to separate the two cells
chromosomes decondense and become thread-like (chromatin)
end of meiosis I
two daughter cells
go into prophase II without doing interphase
plane of division in II is right angle to plane of division in I
prophase II
chromosomes become condensed into individual chromosomes
each chromosomes consists of a centromere with two chromatids attached - only one chromosome from each pair
the nuclear envelop starts to disappear
centrioles become prominent and move to opposite poles
metaphase II
chromosomes line up along the equatorial plane of the cell
spindle fibres attach from the centrioles to the centromere of each chromosome
the nuclear envelope is lost completely
anaphase II
the spindle fibres contract
the centromeres are split
chromatids from each chromosome are pulled towards opposite poles
known as independent assortment of chromatids - cause of genetic variation
telophase II
new nuclear envelops are formed (phospholipid synthesis)
centrioles are replicated
chromosomes start to decondense
cytokinesis II
a cleavage furrow is formed
phospholipids are added to make new cell membrane to separate the two cells
chromosomes decondense and become thread-like (chromatin)
