Chapter 13

Question 1

Sutton and Boveri both proposed that

Answer 1

genes are present on chromosomes in
the early 1900s

Question 2

homologous chromosomes
pair with each other during

Answer 2

meiosis

Question 3

Chromosome Theory

Answer 3

Inheritance patterns of unlinked vs. linked genes. Linked genes do NOT segregate randomly during meiosis

Question 4

Sex determination in Drosophila is based on the
number of

Answer 4

X Chromosomes

Question 5

2 “X”

Answer 5

Female

Question 6

1 “X”

Answer 6

Male

Question 7

Sex determination in humans is based on the

Answer 7

Y Chromosomes

Question 8

“Y” chromosome carries genes for

Answer 8

“maleness”

Question 9

In many organisms, the Y chromosome is

Answer 9

greatly reduced or inactive

Question 10

X-linked genes are present in only

Answer 10

1 copy in males, 2 copys in females

Question 11

Sex-linked traits

Answer 11

controlled by genes on
the X or Y chromosome; show inheritance
patterns different than those of genes on
autosomal chromosomes

Question 12

Dosage compensation ensures

Answer 12

equal gene
expression even though females have 2
“X”s and males have only 1

Question 13

In female cells, 1 “X” is inactivated and
condensed into a

Answer 13

Barr Body

Question 14

Genetic Mosiacs express

Answer 14

the dominant allele in some cells, the
recessive allele in other cells

Question 15

DNA mutations can cause

Answer 15

altered proteins once the genes are transcribed and
translated

Question 16

Altered proteins may not function correctly,
causing a

Answer 16

phenotypic change

Question 17

Some genetic disorders are caused by
changes in

Answer 17

chromosome number

Question 18

Nondisjunction during meiosis can create

Answer 18

gametes having too many or too few
chromosomes

Question 19

Down syndrome is trisomy of chromosome

Answer 19

21

Question 20

Fertilization of nondisjunction
gametes creates

Answer 20

trisomic or
monosomic
individuals

Question 21

The incidence of
Down Syndrome
increases with

Answer 21

female age,
because non-
disjunction
during meiosis
increases with
ageing

Question 22

Nondisjunction of sex chromosomes of
females can result in

Answer 22

XXX triple-X syndrome daughters
XXY sons (Klinefelter syndrome)
XO daughters (Turner syndrome)
XYY sons (Jacob syndrome)
OY nonviable zygotes

Question 23

Cri-du-chat syndrome
occurs when a section
of

Answer 23

chromosome 5 is missing

Question 24

Genomic imprinting occurs when the

Answer 24

phenotype
produced by a particular allele depends on which
parent contributed the allele to the offspring

Question 25

Maternal inheritance

Answer 25

uniparental (one-
parent) inheritance from the mother only

Question 26

Mitochondria are in eggs, but usually not in
the

Answer 26

sperm. So, mitochondria in the
offspring come from the mother.