Part K: Lecture 42

Question 1

euploid (def.)

Answer 1

cell/organism with complete chromosome set

Question 2

euploid can be ___ or ____ or ___ etc.

Answer 2

haploid
diploid
triploid

Question 3

aneuploid (def.)

Answer 3

cell/organism with tooo many or too few of one chromosome

Question 4

aneuploid examples

Answer 4

monosomic (2n-1)
trisomic (2n+1)

Question 5

monosomic (def.)

Answer 5

one less chr

Question 6

trisomic (def.)

Answer 6

one more chr

Question 7

causes of aneuploidy (3)

Answer 7

1) failure during anaphase (microtubules don’t properly pull chr apart)
2)non-disjunction during mitosis
c)non-disjunction during meiosis I or II

Question 8

non-disjunction (def.)

Answer 8

the failure of homologous chromosomes or sister chromatids to separate properly during cell division

Question 9

non-disjunction during mitosis: # of aneuploid cells

Answer 9

two (2)

Question 10

non-disjunction during meiosis I: # of aneuploid cells

Answer 10

four (4)

Question 11

non-disjunction during meiosis II: # of aneuploid cells

Answer 11

two (2)

Question 12

triploid ≠ trisomic why?

Answer 12

triploid: three copies of each chr - non viable in humans
trisomic: three copies of one chr

Question 13

cells work best when there are how many copies of each gene? why?

Answer 13

two (2)
balance in amount of proteins

Question 14

2 consequences of aneuploidy

Answer 14

-monosomy
-trisomy

Question 15

monosomic cell –> _____ —> _____ proteins –> _____

Answer 15

gene imbalance
too few
cell dies

Question 16

trisomic cell –> _____ —> _____ proteins –> _____

Answer 16

gene imbalance
too many
cell dies

Question 17

monsomy vs trisomy: which is worse?

Answer 17

monosomy (greater imbalance)

Question 18

aneuploidy is common in ___

Answer 18

embryos (1/3)

Question 19

aneuploidy is rare in ___

Answer 19

infants

Question 20

aneuploidy can be viable if chromosome is ____ (3)

Answer 20

small (Chr 21)
has few genes (Y)
can be inactivated (X)

Question 21

maternal age effect (def.)

Answer 21

age of mother increases chances of aneuploidy

Question 22

reason for maternal age effect: ___

Answer 22

oogenesis begins in female fetus and arrest in prophase I
↑ time in meiosis = ↑ nondisjunction

Question 23

sex chromosome aneuploidy is usually fixed by ___

Answer 23

dosage compensation (count X chr, turn off all but one)

Question 24

sex chromosome aneuploidy: gene in pseudoautosomal region ____

Answer 24

remains active even in inactivated X chr

Question 25

2 x chr = ___ barr bodies

Answer 25

1

Question 26

3 x chr = ___ barr bodies

Answer 26

2

Question 27

1 x chr = ___ barr bodies

Answer 27

0

Question 28

euploid male and female # of chr

Answer 28

46 chr