Ch 12-2

Question 1

Linked genes are inherited together at ______ rates than unlinked genes.

Answer 1

Higher

Question 2

The recombination frequency for unlinked genes is ______%.

Answer 2

50

Question 3

______ is the process that alters allelic combinations during prophase I of meiosis.

Answer 3

Crossing over

Question 4

___ results from the fertilization of an abnormal diploid egg.

Answer 4

Triploidy

Question 5

______ is the transfer of a chromosome segment to another chromosome.

Answer 5

Translocation

Question 6

______ and ______ are common means of fetal testing.

Answer 6

Amniocentesis, chorionic villus sampling

Question 7

Down syndrome is caused by ______ of chromosome 21.

Answer 7

Trisomy

Question 8

The frequency of aneuploidy increases with ______ age.

Answer 8

Maternal

Question 9

Klinefelter syndrome is characterized by the ______ karyotype.

Answer 9

Xxy

Question 10

Wolf-Hirschhorn Syndrome is caused by a deletion in chromosome ______.

Answer 10

4

Question 11

What is the recombination frequency for completely linked genes?
a) 0%
b) 25%
c) 50%
d) 100%

Answer 11

A

Question 12

Which of the following is NOT a type of structural chromosomal alteration?
a) Deletion
b) Duplication
c) Inversion
d) Nondisjunction

Answer 12

D

Question 13

What is the karyotype for Turner syndrome?
a) XXY
b) XO
c) XXX
d) XYY

Answer 13

B

Question 14

Which syndrome is associated with a deletion on chromosome 5?
a) Down syndrome
b) Turner syndrome
c) Cri du chat syndrome
d) Wolf-Hirschhorn syndrome

Answer 14

C

Question 15

What is the maximum recombination frequency for linked genes?
a) 25%
b) 50%
c) 75%
d) 100%

Answer 15

B

Question 16

Which of the following is a viable monosomy in humans?
a) Monosomy 21
b) Monosomy X
c) Monosomy 18
d) Monosomy Y

Answer 16

B

Question 17

What type of chromosomal alteration results in the Philadelphia chromosome?
a) Deletion
b) Duplication
c) Inversion
d) Translocation

Answer 17

D

Question 18

Which condition is associated with three X chromosomes?
a) Turner syndrome
b) Klinefelter syndrome
c) XXX syndrome
d) XYY syndrome

Answer 18

C

Question 19

What is the frequency of Klinefelter syndrome in individual births?
a) 1/100
b) 1/500 to 1/1000
c) 1/2500
d) 1/10000

Answer 19

B

Question 20

Which process is responsible for the formation of gametes with abnormal chromosome numbers?
a) Mitosis
b) Nondisjunction
c) Crossing over
d) Independent assortment

Answer 20

B

Question 21

True or False: Completely linked genes always result in recombinant offspring.

Answer 21

False. Completely linked genes result in all offspring being parental type.

Question 22

True or False: Aneuploidy is the most common reason for early stage pregnancy loss.

Answer 22

T

Question 23

True or False: Polyploidy is well-tolerated in humans.

Answer 23

False. Polyploidy is not tolerated in humans but is tolerated by some other organisms.

Question 24

True or False: Inversions always result in a change in gene copy number.

Answer 24

False. Inversions do not change gene copy number but may alter gene regulation.

Question 25

True or False: The frequency of aneuploidy decreases with maternal age.

Answer 25

False. The frequency of aneuploidy increases with maternal age.

Question 26

True or False: XYY individuals typically show no phenotypic effects.

Answer 26

T

Question 27

True or False: Turner syndrome is the only known viable monosomy in humans.

Answer 27

T

Question 28

True or False: Cri du chat syndrome is caused by a duplication on chromosome 5.

Answer 28

False. Cri du chat syndrome is caused by a deletion on chromosome 5.

Question 29

True or False: Nondisjunction can occur during both meiosis and mitosis. .

Answer 29

T

Question 30

True or False: The Philadelphia chromosome is associated with Down syndrome.

Answer 30

False. The Philadelphia chromosome is associated with chronic myelogenous leukemia (CML).

Question 31

What is complete linkage?

Answer 31

Genes on the same chromosome, very close together, resulting in 0% recombination and all offspring being parental type.

Question 32

Define aneuploidy.

Answer 32

An abnormal chromosome number due to nondisjunction, resulting in either monosomy (one copy) or trisomy (three copies) of a chromosome.

Question 33

What is the Philadelphia chromosome?

Answer 33

A chromosomal alteration resulting from a translocation, implicated in chronic myelogenous leukemia (CML).

Question 34

What is a centiMorgan?

Answer 34

A unit of genetic distance equal to 1% recombination frequency or 1 map unit.

Question 35

What is polyploidy?

Answer 35

The presence of more than two complete sets of chromosomes in all somatic cells.

Question 36

What is Turner syndrome?

Answer 36

A condition resulting from monosomy X (XO), occurring in 1/2500 births and generally causing sterility.

Question 37

What causes Cri du chat syndrome?

Answer 37

A deletion on chromosome 5, resulting in a characteristic cat-like cry and intellectual disability.

Question 38

What is mosaicism?

Answer 38

A condition where an individual has two or more genetically distinct cell populations, often due to mitotic nondisjunction.

Question 39

What is a karyotype?

Answer 39

A visual representation of an individual's chromosomes, arranged by size and banding pattern.

Question 40

What is the Barr body?

Answer 40

The inactivated and condensed X-chromosome in XX individuals.