Chromosome variation

Question 1

Polyploidy

Answer 1

2+ sets of chromosomes

Question 2

Triploids

Answer 2

Are sterile because 1 in 2 gametes is nonviable, has uneven amount of genetic material because homologs cannot separate

Question 3

Tetraploids

Answer 3

Are fertile because their homologs can separate evenly

Question 4

Autopolyploid

Answer 4

Chromosome sets are all identical, chromosomes are derived from same species.
Spontaneous doubling of ones own genetic mateiral

Question 5

Autopolyploid caused by mitosis

Answer 5

DNA replicates and sister chromatids separate but cell fails to divide creating an autotetraploid

Question 6

Autopolyploid causes by meiosis

Answer 6

Homologous pairs do not separate in meiosis 1 so gamete is still 2n when fertilized by a normal gamete and they produce a triploid zygote (not gamete)

Question 7

Almost every kind of commercial fruit is a polyploid

Answer 7

Because consumers prefer seedless fruits and polyploid fruits with uneven numbers produce fewer seeds and bigger fruits

Question 8

Allopolyploidy

Answer 8

Polyploids resulting from cross between 2 different species

Question 9

Can a sterile zygote hybrid continue to grow and propagate asexually?

Answer 9

Yes

Question 10

Aneuploidy

Answer 10

Condition of a diploid genome which lacks a chromosome or has an extra chromosome

Question 11

Hyperploidy

Answer 11

Trisomies (2n+1)

Question 12

Hypoploidy

Answer 12

Monosomies (2n-1)

Question 13

Is Aneuploidy caused by meiotic nondisjunction?

Answer 13

Yes

Question 14

All monosomies are aborted in early pregnancy? True or False

Answer 14

False Monosomies pertaining to sex chromosomes arent.

Question 15

Trisomy 21

Answer 15

Only nondisjunction event where individual lives into adulthood.
Chromosome 21 is the shortest chromosome so dosage of genes is not as drastically different

Question 16

Trisomy 13 and 16

Answer 16

Both Live birth death in infancy

Patau and Edward

Question 17

Aneuploid conditions involving sex chromosomes

Answer 17

Are much milder in symptoms than autosomal trisomies due to x-inactivation.

Question 18

96% of cases of down syndrome occur due to
80% occur
20%

Answer 18

meiotic nondisjunction, oogenesis, spermatogenesis

Question 19

Klinefelter syndrome

Answer 19

XXY

Question 20

Turner syndrome

Answer 20

X0

Question 21

Frequency of trisomy’s increase with age

Answer 21

True

Question 22

Deletion

Answer 22

missing chromosome segment, under the umbrella of hypoploidy

Question 23

Duplication

Answer 23

extra chromosome segment, under umbrella of hyperploidy

Question 24

Inversion

Answer 24

one section of segment flips 180º, can be pericentric (involves centromere) or paracentric (does not involve centromere)
In order to correct itself, an inversion loop can form where homologous genes match through chromosomal arm twisting on itself
Inversion loop increases chance of nondisjunction (may break off spindle)

Question 25

Translocation

Answer 25

segment from one chromosome is detached and reattached to a non-homolog
Reciprocal translocation - exchange of segments from non homologs
Because of the translocation, 4 chromosomes become involved and form a tetravalent
Cross-like configuration forms where homologs try to match up

Question 26

Compound chromosomes

Answer 26

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