Deck 6: Cytogenetics - Karyotypes and Chromosome Aberrations

Question 1

Using fetal DNA from the mother's blood for prenatal testing is a noninvasive procedure.

Answer 1

True

Question 2

About ____ percent of children with Down syndrome are severely intellectually disabled.

A) five
B) ten
C) twenty-five
D) thirty
E) forty

Answer 2

B

Question 3

Submetacentric describes a chromosome whose telomeres are attached to the centromeres.

Answer 3

False

Question 4

Trisomy 21 is the only autosomal trisomy that allows survival into adulthood.

Question 5

Polyploidy is characterized by ____.

A) the failure of homologous chromosomes to separate properly during meiosis
B) a condition in which one chromosome is present in three copies
C) a condition in which one member of a chromosomal pair is missing
D) a chromosomal number that is not an exact multiple of the haploid set
E) a chromosomal number that is a multiple of the normal haploid chromosomal set

Question 6

One important difference between amniocentesis and chorionic villus sampling is that ____.

A) chorionic villus sampling is more routine
B) amniocentesis can diagnose chromosome disorders, while chorionic villus sampling cannot
C) chorionic villus sampling can be done earlier in the pregnancy than amniocentesis
D) maternal risks are higher with chorionic villus sampling
E) the risk of miscarriage is higher with amniocentesis than with chorionic villus sampling

Question 7

Leukemia is often associated with chromosomal translocations.

Question 8

Chromosomes are usually studied and photographed while they are in anaphase of mitosis.

Question 9

Studies of sex chromosome aneuploidy reveal that ____ necessary for survival.

A) the X chromosome is not
B) the Y chromosome is not
C) two copies of the X chromosome are
D) two copies of the Y chromosome are
E) at least one copy of both the X and the Y chromosome is

Question 10

The letters G,Q,R,and C,used to describe the appearance of chromosomes,refer to the ____.

A) position of the bands
B) staining procedure used to reveal the bands
C) number of arms per chromosome
D) number of centromeres per chromosome
E) position of the centromeres

Question 11

Spindle fibers attach to the ____ of a chromosome during cell division.

A) centromere
B) telomere
C) cell membrane
D) short arms
E) gametes

Question 12

Down syndrome can be caused by either trisomy 21 or a Robertsonian translocation.

Question 13

When constructing a karyotype,the chromosome images are arranged in pairs according to ____________________ and ____________________.

A) size; telomere location
B) size; centromere location
C) banding pattern; centromere location
D) banding pattern; telomere location
E) size; banding pattern

Question 14

The risk for Down syndrome increases ____.

A) when the mother is over thirty-five years old
B) when the father is over thirty-five years old
C) when the father is over fifty years old
D) for dizygotic twins
E) for monozygotic twins

Question 15

Turner syndrome is not associated with intellectual disability.

Question 16

If nondisjunction occurs during meiosis I,____.

A) two gametes will be normal and two will be missing one chromosome
B) two gametes will be normal and two will have one extra chromosome
C) three gametes will be normal and one will have two extra chromosomes
D) all gametes will be normal
E) all gametes will be abnormal

Question 17

Viral infections are not considered a risk factor for autosomal trisomy because a virus cannot affect human chromosome arrangement.

Question 18

The most common type of polyploidy in humans is ____.

A) trisomy
B) monosomy
C) triploidy
D) tetraploidy
E) haploidy

Question 19

The risk of having a child with Down syndrome due to a chromosomal translocation is independent of maternal age.

Question 20

Amniocentesis is not performed on mothers over the age of thirty-five.

Question 21

In a(n)____ translocation,two nonhomologous chromosomes exchange parts and no genetic information is gained or lost from the cell in the exchange.

A) cri du chat
B) XXY
C) copy number
D) Robertsonian
E) reciprocal

Question 22

Approximately 40% of all children with Down syndrome have congenital ____________________ defects.

Question 23

One type of polyploidy is ____.

A) aneuploidy
B) trisomy
C) triploidy
D) deletion
E) translocation

Question 24

One technique for chromosome analysis is called ____________________,which uses chromosome-specific DNA sequences attached to fluorescent dyes to target specific chromosomal regions.

Question 25

There are ____________________ chromosomes in a human tetraploid cell.

Question 26

Researchers have suggested that all live-born infants with Turner syndrome are actually ____________________,with both 46,XX and 45,X cells present in their bodies.

Question 27

Fragile sites appear as ____________________ or ____________________ at specific sites on a chromosome.

Question 28

One possible explanation for why ____________________ is a primary risk factor for autosomal trisomy is that oocytes remain in meiosis I until ovulation,which could take place many years after birth,making them more susceptible to damage.

Question 29

About ____ percent of all newborns are affected with an abnormal karyotype.

A) 0.001
B) 0.01
C) 0.05
D) 0.5
E) 1.0

Question 30

The major physical symptom associated with Klinefelter syndrome is ____.

A) facial deformation
B) fertility problems
C) short stature
D) intellectual disability
E) heart abnormalities

Question 31

The karyotype designation for an infant with a deletion in the short arm of chromosome 5 (cri du chat syndrome)is ____________________

Question 32

Regions at the ends of chromosomes that prevent chromosomes from sticking to each other are called ____.

A) satellites
B) telomeres
C) centromeres
D) q zones
E) p zones

Question 33

A deletion in the short arm of chromosome 5 is associated with ____ syndrome,which causes intellectual disability,defects in facial development,and an abnormal larynx.

A) Down
B) Klinefelter
C) Turner
D) cri du chat
E) XYY

Question 34

A chromosome that has a centrally-placed centromere is called ____________________.

Question 35

Autism,Alzheimer disease,Parkinson's disease,and schizophrenia are all associated with ____.

A) copy number variants
B) fragile sites
C) inversions
D) deletions
E) translocations

Question 36

The long arm of a chromosome is called the ____________________ arm.

Question 37

Deletion of an entire autosome ____.

A) causes XYY syndrome
B) causes Down syndrome
C) causes no physical symptoms
D) is lethal
E) is called polyploidy

Question 38

More than ____ percent of couples decide to terminate a Down syndrome pregnancy.

A) ten
B) thirty
C) fifty
D) seventy
E) ninety

Question 39

 Most triploid zygotes probably arise from ____.

A) incomplete meiosis I
B) incomplete meiosis II
C) incomplete mitosis
D) nondisjunction
E) dispermy

Question 40

The karyotype designation for a female with X chromosome trisomy is ____________________.

Question 41

Part of a chromosome moves to another,nonhomologous chromosome during ____________________.

Question 42

Changes in the number of copies of chromosomal DNA segments and the genes they contain are called ____________________.

Question 43

Karyotypes prepared from chorionic villus cells can be used to identify many ____________________ abnormalities.

Question 44

Define the term translocation and describe the two major types and their phenotypic consequences.

Question 45

Define aneuploidy and describe the sex chromosome aneuploidies involved in Turner syndrome,Klinefelter syndrome,and XYY syndrome; list characteristics of each disorder.

Question 46

List at least three types of information provided by a karyotype and interpret the chromosomal structural abnormality written as 46,XX,t(18q).

Question 47

There are no cases of -XX or Y individuals,but X individuals do exist.Propose an explanation for this statistic.

Question 48

Free fetal DNA (ffDNA)originates from the breakdown of fetal cells and their nuclei in the ____________________.

Question 49

A chromosome whose centromere is placed very close to,but not at,one end is called a(n)____________________ chromosome.

Question 50

Describe two processes that would result in a triploid zygote.

Question 51

A condition in which both copies of a chromosome are inherited from one parent is called ____________________.

Question 52

Amniocentesis collects cells from the fluid surrounding the fetus in order to prepare a(n)____________________.

Question 53

Define the terms triploidy and autosomal trisomy and describe characteristics and consequences of each genetic disorder.

Question 54

Describe normal embryo formation and two mechanisms of nondisjunction represented in the figure and identify the consequences of these chromosomal anomalies.

Question 55

The FRAX A site near the tip of the long arm of the X chromosome is associated with a form of intellectual disability known as Martin-Bell syndrome,or ____________________.

Question 56

Early investigators associated the tendency to violent criminal behavior with the ____________________ karyotype,but there is no evidence of a direct link between the two.

Question 57

Explain how to determine if a nondisjunction occurred during meiosis I or meiosis II and what the genetic consequences are for the resulting fertilized gametes.

Question 58

Almost all chromosomally abnormal embryos and fetuses are ____________________ as pregnancy progresses.

Question 59

Explain how the terms diploid and haploid relate to human chromosome number in both autosomes and sex cells.

Question 60

Explain why geneticists believe that almost all chromosomally abnormal embryos and fetuses are eliminated as pregnancy progresses.