chromosomes

karyotype

imaging of stained chromosomes

ploidy

number of sets of chromosomes

diploid

2 copies of each chromosome; are homologous pairs

giesma stains

dye used to stain the chromosomes

metacentric

p and q arm are the same length

submetacentric

p arm is slightly smaller than q arm

acrocentric

p arm is significantly smaller than q arm

telocentric

p arm not seen

homologous chromosomes

pair of chromosomes, have same banding pattern but different nucleotide sequence

interphase

majority of cell cycle, cell growth

G1 phase

growth phase, will be diploid, 1 chromatid per chromosome

S phase

synthesis, DNA replication, 2 sister chomatids per chromosome, DNA amount stays the same

G2 phase

DNA growth after synthesis, chromatid and DNA amount stays the same

G0 phase

No cell division or growth

phases of mitosis

Prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis

Interphase

Before cell cycle, cell growth, DNA is relaxed

prophase

1st phase, DNA condenses, microtubules forming from centrosomes from the ends, nuclear envelope disappears

centrosome

form at centromere, tight DNA

cohesin rings

wrap around 2 DNA molecules at centromere, made of protein

kinetochore

specific sight at centromere

The spindle

microtubules are made of tubulin, connect centrosome to kinetochore on each chromatid, polarity

seperase

breaks down cohesin during anaphase separting sister chromatids

binucleated cells

failure of cytokinesis, success in mitosis

endoreplication

failure of mitosis and cytokinesis, but successful DNA replication

end of meiosis I

haploid with 2 chromatids per chromosome, 2 chromosomes

end of meiosis II

haploid with 1 chromatid per chromosome, 2 chromosomes

end of anaphase I

goes from diploid to haploid, chromosome number splits in half

end of anaphase II

goes to one chromatid per chromosome

anaphase I

number of chromosomes, chromatids, and ploidy stay the same as before

chiasma

point where homologous chromosome interact to cross over

when does crossing over occur

during prophase I and metaphase I

spermatogenesis

gametes become sperm after meiosis II

oogenesis

after meiosis I there one polar body and a big egg. after meiosis II there’s 3 polar bodies and one ovum

nondisjunction at meiosis I

2 gametes have one less haploid number, 2 gametes have one more

nondisjunction at meiosis II

2 gametes are normal, one has one less haploid number, one has one more