L4: chromosomes and inheritance

Question 1

structure of chromosomes

Answer 1

a double strand wrapped around proteins
unreplicated chromosomes are loosely coiled

Question 2

anisogamy

Answer 2

unequal sized gametes, small gametes are male and larger are female

Question 3

exceptional progeny

Answer 3

rare events of chromosomal nondisjunction
product of nondisjunction

Question 4

what can nondisjunction in either parent result in?

Answer 4

abnormal numbers of sex chromosomes in progeny

Question 5

what are reciprocal crosses?

Answer 5

one cross where mutant phenotype is carried by the mom, the other cross where the mutant phenotype is carried by dad. for sex-linked traits, the crosses have different outcomes

Question 6

nondisjunction

Answer 6

chromosomes fail to properly segregate in meiosis
(meiotic error)

Question 7

polyploidy

Answer 7

presence of extra sets of chromosomes more than 2n

Question 8

aneuploidy

Answer 8

a numerical change in part of the genome

Question 9

inversion

Answer 9

a rearrangement that reverses the order of a linear array of genes in a chromosome a circle on rope, the twist shows the inversion

Question 10

translocation

Answer 10

when a segment from one chromosome is detached and reattached to a different (nonhomologous) chromosome

Question 11

reciprocal translocation

Answer 11

pieces of two nonhomologous chromosomes are exchanged without any net loss of genetic material

Question 12

while balanced translocation won’t result in loss of genetic material, where might there be difficulties in other places?

Answer 12

reproductive difficulties

Question 13

how are compound chromosomes formed?

Answer 13

they are formed by the fusion of homologous chromosomes, sister chromatids, or homologous chromosome segments

Question 14

what are robertsonian translocations?

Answer 14

fusion of nonhomologous chromosomes