lec 3. meiosis

Question 1

diploids

Answer 1

have two version of each chromosome

Question 2

haploids

Answer 2

have one homologue of the chromosome

Question 3

meiosis

Answer 3

division that results in 4 haploid daughter cells

2x mitosis without second interphase

Question 4

prophase I of meiosis

Answer 4

replicated homologous chromosomes find each other - non-sister chromatids exchange genetic material

Question 5

anaphase I of meiosis

Answer 5

the duplicated chromosomes are pulled apart

Question 6

metaphase I of meiosis

Answer 6

sister chromatids line up at equatorial plate

Question 7

anaphase II of meiosis

Answer 7

sister chromatids are pulled apart

Question 8

How kinetochore attachment defines how chromosomes segregate during cell division.

Answer 8

• crossing over links sister chromatids
• cohesin is only removed from arms, not the middle
• kinetochore microtubules attach to kinetochores on BOTH chromatids

Question 9

polyploidy

Answer 9

difference of one or more complete sets of chromosomes

Question 10

aneuploidy

Answer 10

abnormal number of chromosomes caused by chromosome nondisjunction

Question 11

monosomy

Answer 11

1 copy of a chromosome

• Y (not viable
• X (Turners, 99% abort)

Question 12

trisomy

Answer 12

3 copies of a chromosome

• trisomy 22
• trisomy 18 (Edwards syndrome)
• additional sex chromosome (XXX, XXY, XYY)

Question 13

nullisomy

Answer 13

missing pair of chromosome

Question 14

explanation for phenotypes

Answer 14

haploinsufficiency - gene is expressed from both allels and dose matters

Question 15

synaptonemal complex

Answer 15

cohesin on DNA binds to axial cores which are cross-linked with transverse filaments to allow exchange genetic information