Ch. 8

Question 1

What field of genetics involves the microscopic examination of chromosomes?

Answer 1

Cytogenetics

Question 2

What do cytogeneticists use to identify and classify chromosomes?

Answer 2

1. Location of the centromere
2. Size
3. Banding patterns

Question 3

What is a micrograph in which all of the chromosomes within a single cell are arranged in a standard fashion?

Answer 3

A karyotype

Question 4

Chromosomes are treated with ____ to produce characteristic banding patterns

Answer 4

Stains

Question 5

What is a commonly used stain that produces both light and dark bands

Answer 5

Giemsa

Question 6

In humans ____ G bands are seen in metaphase and ____ G bands are seen in prometaphase?

Answer 6

300, 800

Question 7

How is a banding pattern useful?

Answer 7

1. distinguishes individual chromosomes from each other
2. Detects changes in chromosome structure
3. Reveals evolutionary relationships

Question 8

For chromosome position, where is metacentric?

Answer 8

In the middle

Question 9

For chromosome position, where is submetacentric?

Answer 9

Slightly off center from the middle

Question 10

For chromosome position, where is arcocentric?

Answer 10

Significantly off center from the middle but not completely to one end

Question 11

For chromosome position, where is telocentric?

Answer 11

Completely to one end of the chromosome

Question 12

What are two ways in which the total amount of genetic material in the chromosome can change?

Answer 12

deletions and duplications

Question 13

What are two ways in which the total amount of genetics material remains the same but is rearranged?

Answer 13

inversions and translocations

Question 14

What is the loss of a chromosomal segment?

Answer 14

deletion

Question 15

What is the repetition of a chromosomal segment compared to a normal chromosome?

Answer 15

duplication

Question 16

What is a change in the direction of part of the genetic material along a single chromosome?

Answer 16

inversion

Question 17

What is a segment of one chromosome becomes attached to a different chromosome

Answer 17

translocation

Question 18

What is a translocation where a piece of a chromosome is attached to another chromosome?

Answer 18

simple translocation

Question 19

What is a translocation where two different types of chromosomes exchange pieces, producing two abnormal translocation chromosomes

Answer 19

reciprocal translocation

Question 20

When a chromosome is broken into two pieces the one without the centromere is eventually lost, what is this deletion called?

Answer 20

terminal deletion

Question 21

When a chromosome breaks into two places the central fragment is lost and the two outer pieces reattach, what is this deletion called?

Answer 21

interstitial deletion

Question 22

What is more severe when they occur, a duplication or a deletion?

Answer 22

Deletion

Question 23

What can cause misalignment between homolgous chromosomes leading to a deletion?

Answer 23

Repetitive sequences

Question 24

Repetitive sequences cause what recombination results?

Answer 24

nonallelic homologous

Question 25

What consists of two or more genes in a single species that are derived from the same ancestral gene?

Answer 25

gene family

Question 26

Homologous genes within a single species are called what

Answer 26

paralogs

Question 27

What is a segment of DNA that caries in the copy number among members of the same species?

Answer 27

Copy number variation

Question 28

What are the possible mechanisms of CNV?

Answer 28

1. nonallelic homologous recombination 2. proliferation of transposable elements 3. errors in DNA replication

Question 29

What type of inversion occurs around the centromere?

Answer 29

pericentric inversions

Question 30

What type of inversion occurs outside of the centromere

Answer 30

paracentric inversions

Question 31

When a inversion occurs within a vital gene thereby separating it into two nonfunctional parts, what is this called?

Answer 31

break point effect

Question 32

Individuals can carry one normal copy of a chromosome and a inverted chromosome copy and present phenotypically normal? T/F

Answer 32

True

Question 33

What are the heterozygotes that have one inverted chromosome called?

Answer 33

Inversion heterozygotes

Question 34

For the normal and inversion chromosome to synapse properly a ______ must form

Answer 34

inversion loop

Question 35

If crossing over occurs within then inversion loop it produces _____ chromosomes

Answer 35

Highly abnormal

Question 36

How do reciprocal translocations arise

Answer 36

1. chromosomal breakage and DNA repair 2. abnormal crossovers

Question 37

Reciprocal translocations lead to rearranged material, not a total change in material so they are sometimes called what?

Answer 37

balanced translocations

Question 38

Unbalanced translocations occur when genetic material is ____ or ____

Answer 38

duplicated, deleted

Question 39

Familial down syndrome is a condition where the majority of chromosome ____ is attached to chromosome _____

Answer 39

21, 14

Question 40

Familial down syndrome is an example of _____ translocation

Answer 40

Robertsonian

Question 41

*Breaks occur near the centromeres of two non- homologous acrocentric chromosomes * The small acentric fragments are lost * The larger fragments fuse at their centromeric regions to form a single chromosome which is metacentric or submetacentric

Answer 41

Robertsonian translocation familial down syndrome

Question 42

What is it called when there is variation in the number of complete sets of chromosomes?

Answer 42

euploid (polyploidy)

Question 43

What is it called when there is variation in the number of particular chromosomes in a set

Answer 43

aneuploid, (trisomy and monosomy)

Question 44

Aneuploid produces offspring that are ____ to survive than euploid

Answer 44

Less likely

Question 45

Trisomy 13

Answer 45

Patau

Question 46

Trisomy 18

Answer 46

Edward

Question 47

Trisomy 21

Answer 47

Down

Question 48

XXY

Answer 48

Klinefelter

Question 49

XYY

Answer 49

Jacobs

Question 50

XXX

Answer 50

Triple X

Question 51

X0

Answer 51

Turner

Question 52

When does Down Syndrome's nondisjunction most commonly occur?

Answer 52

meiosis I