Chapter 15: Foundations of Genetics: Chromosomes and Human Genetics

Question 1

what type is dominant

Answer 1

wild represented by a superscript +

Question 2

what type is recessive

Answer 2

mutant

Question 3

Genes located on a sex chromosome

Answer 3

Sex-linked Genes

Question 4

Genes located on the same chromosome

Answer 4

Linked genes

Question 5

Inherited together as a unit

Answer 5

linked genes

Question 6

was the first person to associate a specific gene with a specific chromosome, early in the
1900s.

Answer 6

Thomas Hunt Morgan

Question 7

what did Morgan discover?

Answer 7

Mendel’s heritable units
were chromosomes

Question 8

Morgan studied heredity in what?

Answer 8

fruit flies

Question 9

what chromosomes do males have?

Answer 9

XY

Question 10

what chromosomes do females have

Answer 10

XX

Question 11

which chromosome is longer X or Y

Answer 11

X

Question 12

how many genes do X chromosomes have?

Answer 12

1,100 genes

Question 13

what kind of traits do X chromosomes carry?

Answer 13

sexual traits as well as non-sexual traits
such as blood-clotting functions.

Question 14

what kind of traits do Y chromosomes carry?

Answer 14

sexual traits

Question 15

how many genes do Y chromosomes carry?

Answer 15

78 genes

Question 16

This genetic disorder impairs the blood’s ability to
clot and causes prolonged bleeding.

Answer 16

Hemophilia

Question 17

determined by genes found only on
the X chromosome

Answer 17

(sex linked)

Question 18

A person who is what for the hemophilia
gene has the disease

Answer 18

homozygous

Question 19

example of sex linked genes

Answer 19

Hemophilia
and
Color blindness

Question 20

one of the 2 X chromosomes in
each cell randomly what?

Answer 20

condenses

Question 21

what happens when one of the 2 X chromosomes in each cell condenses?

Answer 21

it becomes inactive

Question 22

condensed X chromosome

Answer 22

Barr Body

Question 23

when can the Barr Body be seen in nucleus?

Answer 23

during interphase

Question 24

Genes that are located on the
same chromosome tend to be
inherited together and are called what?

Answer 24

linked genes

Question 25

Offspring with a phenotype matching one of the parental (P) phenotypes are called

Answer 25

parental types

Question 26

new combinations of traits

Answer 26

nonparental phenotypes

Question 27

Offspring with nonparental phenotypes (new combinations of traits) are called what?

Answer 27

recombinant types, or recombinants

Question 28

a what percent frequency of recombination is observed for any two genes on different chromosomes

Answer 28

50% frequency

Question 29

break the physical connection between genes on the same chromosome

Answer 29

crossing over of homologous chromosomes

Question 30

who constructed the genetic map?

Answer 30

Alfred Sturtevant

Question 31

an ordered list of the genetic loci along a particular chromosome

Answer 31

genetic map

Question 32

predicted that the farther apart two genes are, the higher the probability that a crossover will occur between them and therefore the higher the recombination frequency

Answer 32

Alfred Sturtevantis

Question 33

is a genetic map of a chromosome based on recombination frequencies

Answer 33

linkage map

Question 34

Distances between genes can be expressed as

Answer 34

map units

Question 35

one map unit represents what?

Answer 35

1% recombination frequency

Question 36

Map units indicate what?

Answer 36

relative distance and order,not precise locations of genes

Question 37

Genes that are far apart on the same chromosome can have a recombination frequency near what

Answer 37

50%

Question 38

Changes in an organisms chromosome structure and genetic material. They may have a positive, neutral or negative effect on the life of the organism.

Answer 38

mutations

Question 39

types of mutation

Answer 39

Deletion Duplication Inversion Translocation

Question 40

A fragment of the chromosome breaks off and can be lost when the cell divides.

Answer 40

Deletion

Question 41

The chromosome fragment attaches to its homologous chromosome which will then carry two copies of a certain set of genes.

Answer 41

Duplication

Question 42

Fragment reattaches to the original chromosome in the reverse orientation.

Answer 42

Inversion

Question 43

Fragment of an original chromosome joins a non-homologous chromosome.

Answer 43

Translocation

Question 44

where individuals have one extra or one fewer chromosome

Answer 44

Aneuploidy

Question 45

what causes Aneuploidy

Answer 45

nondisjunction

Question 46

most miscarriages are what?

Answer 46

Aneuploids

Question 47

individuals have three or more of each type of chromosome

Answer 47

Polyploidy

Question 48

polyploidy could occur when?

Answer 48

if diploid zygote failed to divide after DNA/Chromosomes were replicated = 4n, tetraploidy

Question 49

These individuals have an extra chromosome 21 (trisomy-21), but only two of all the other chromosome types.

Answer 49

Down Syndrome

Question 50

symptoms of Down Syndrome

Answer 50

* moderate to several mental impairment * 40% develop heart defects * abnormal development of the skeleton * weak muscles * speech and motor skills develop slowly

Question 51

Frequency of Trisomy 21 (Down Syndrome) correlates with what?

Answer 51

Age of the mother

Question 52

what is believed to contribute to increased frequency on non- disjunction.

Answer 52

long period of inactivity

Question 53

All the eggs that a female will ever have are present in her body when?

Answer 53

at the time of her birth!!!