Deck 24: Genetics and Genomics

Question 1

An allele that masks the effect of another is

A) homozygous.
B) heterozygous.
C) recessive.
D) dominant.

Answer 1

D

Question 2

The two types of information needed to predict the inheritance pattern of a trait are

A) the way genes are distributed in meiosis and the way that they come together when sperm joins egg.
B) the health of the mother and the father.
C) the way mitosis distributes the alleles of a gene and whether those alleles are dominant or recessive.
D) the age at which the trait appears and how it affects males or females.

Answer 2

A

Question 3

A karyotype is

A) a diagram that represents family relationships.
B) a size-ordered chart of chromosomes.
C) a genome sequence.
D) a website that lists genes and the proteins they encode.

Answer 3

B

Question 4

The term "exome" refers to

A) the parts of the genome that determine sex.
B) the protein-encoding parts of the genome.
C) the parts of the genome that lie exteriorly along the chromosomes.
D) the set of RNAs made in a particular cell type under specific conditions.

Question 5

An allele that is not expressed in the heterozygous condition is

A) recessive.
B) dominant.
C) autosomal.
D) codominant.

Question 6

A gene is

A) a DNA sequence that contains the information for producing one type of protein.
B) a structure that contains chromosomes.
C) an amino acid sequence that contains the information for producing a particular DNA sequence.
D) the collection of all of the protein-encoding DNA sequences on a particular chromosome.

Question 7

The origin of the 46 chromosomes in a human zygote is

A) all from the sperm cell.
B) half from DNA and half from RNA.
C) half from the sperm and half from the egg.
D) all from the egg.

Question 8

A person normally has two alleles of a gene because

A) DNA only comes in two forms.
B) one allele of a gene is carried on each of two homologous chromosomes.
C) there isn't enough DNA to accommodate more than this.
D) all genes come in only two varieties.

Question 9

A gene typically has many alleles because

A) humans have many traits.
B) a chromosome has many genes.
C) a DNA sequence can vary in many ways.
D) a protein sequence can vary in many ways.

Question 10

The genotypes and phenotypes that result from a cross of AA and Aa (A = normal pigmentation and a = albinism) are

A) phenotypes - all normal; genotypes - 50% homozygous dominant and 50% heterozygous.
B) phenotypes - 50% normal and 50% albino; genotypes - all heterozygous.
C) phenotypes - 75% norma and 25% albino; genotypes - 75% heterozygous and 25% homozygous.
D) phenotypes - all albino; genotypes - 50% heterozygous and 50% homozygous recessive.

Question 11

The genotypes and phenotypes that result from the cross of Aa and Aa (A = normal pigmentation and a = albinism) are

A) phenotypes-75% normal and 25% albino; genotypes-25% homozygous dominant and 50% heterozygous and 25% homozygous recessive.
B) phenotypes-50% normal and 50% albino; genotypes-all homozygous recessive.
C) phenotypes-50% normal and 50% albino; genotypes-50% homozygous recessive and 50% homozygous dominant.
D) phenotypes-25% normal and 75% albino; genotypes-25% homozygous dominant and 50% heterozygous and 25% homozygous recessive.

Question 12

Genetics is the study of

A) sperm and eggs.
B) the effect of the environment on health.
C) inheritance of characteristics.
D) DNA.

Question 13

The processes that pass genetic information from generation to generation are

A) mitosis and fertilization.
B) meiosis and fertilization.
C) mitosis and meiosis.
D) interactions of DNA and the environment.

Question 14

The phenotypes and genotypes that result from a cross of Aa and aa (A = normal pigmentation and a = albinism) are

A) phenotypes-all normal; genotypes-50% heterozygous and 50% homozygous recessive.
B) phenotypes-all albino; genotypes-all homozygous recessive.
C) phenotypes-50% normal and 50% albino; genotypes-50% heterozygous and 50% homozygous recessive.
D) phenotypes-all albino; genotypes-50% heterozygous and 50% homozygous recessive.

Question 15

The two general types of chromosomes are

A) autosomes and allosomes.
B) sex chromosomes and allosomes.
C) sex chromosomes and autosomes.
D) X and Y chromosomes.

Question 16

An individual who is homozygous dominant for a trait can be symbolized

A) AA.
B) Aa.
C) aa.
D) none of the above.

Question 17

The human genome consists of

A) DNA, most of which encodes protein.
B) DNA, most of which does not encode protein.
C) protein, most of which encodes DNA.
D) protein, most of which does not encode DNA.

Question 18

How alike are our genomes?

A) About 10%
B) About 25%
C) About 75%
D) Nearly 100%

Question 19

Identical alleles are said to be

A) homozygous.
B) heterozygous.
C) recessive.
D) dominant.

Question 20

Different alleles of the same gene are said to be

A) homozygous.
B) heterozygous.
C) recessive.
D) dominant.

Question 21

A procedure used to obtain enough fetal tissue sampled through the cervix to test for genetic disorders without culturing cells is

A) amniocentesis.
B) chorionic villus sampling.
C) ultrasonography.
D) fetal cell sorting.

Question 22

In a simple dominant-recessive inheritance pattern, what percentage of the offspring would exhibit the dominant trait if one parent is heterozygous and the other is homozygous recessive?

A) 25%
B) 50%
C) 75%
D) 100%

Question 23

The approximate number of protein-encoding genes on the Y chromosome is

A) >1,500.
B) 231.
C) 10.
D) greater in males than females.

Question 24

Cells from a woman with Turner syndrome have

A) an extra X chromosome.
B) one X and two Y chromosomes.
C) only one X chromosome.
D) no sex chromosomes.

Question 25

A human cell with 46 chromosomes is

A) aneuploid.
B) euploid.
C) polyploid.
D) haploid.

Question 26

An example of a sex-influenced trait is

A) baldness.
B) hemophilia.
C) colorblindness.
D) hypertension.

Question 27

Polydactyly is an example of a trait that is both ___________ and variably expressive.

A) incompletely penetrant
B) pleiotropic
C) multifactorial
D) completely penetrant

Question 28

A multifactorial trait is determined by

A) only environmental factors.
B) only by genetic factors.
C) neither genetic nor environmental factors.
D) one or more genes and the environment.

Question 29

The chemical group that binds to DNA causing genomic imprinting is

A) methyl.
B) RNA.
C) a transcription factor.
D) an amino acid.

Question 30

In incomplete dominance,

A) the heterozygous phenotype is intermediate between that of either homozygote.
B) one allele masks the effect of the other.
C) one allele is inactive.
D) only one sex is affected.

Question 31

A bell curve is characteristic of the distribution of phenotypes of a multifactorial trait because

A) the phenotypes in the middle of the curve correspond to fewer genotypes than the phenotypes at the ends of the distribution.
B) the phenotypes at the ends of the curve correspond to fewer genotypes than the phenotypes at the middle of the distribution.
C) most people are average for the trait.
D) people at the extreme ends of the distribution do not survive to reproduce.

Question 32

The nuances of eye color arise from

A) the numbers of rods and cones in the retina.
B) the way pigments are deposited in the iris.
C) how much vitamin A is in a person's diet.
D) multiple alleles of at least 10 genes.

Question 33

Hemophilia A is

A) due to an X-linked dominant gene.
B) passed from affected males to their sons.
C) more common in females.
D) a defect in the clotting mechanism.

Question 34

Down syndrome is caused by

A) nondisjunction or a translocation.
B) the karyotype XXY.
C) an extra Y chromosome.
D) a missing autosome.

Question 35

In von Willebrand disease, which is either autosomal recessive or autosomal dominant, clotting time slows and the person bruises and bleeds easily. Not everyone who inherits the disease genotype actually develops the phenotype. Affected individuals have differing degrees of difficulty in clotting of blood. This condition is

A) completely penetrant, variably expressive, and not genetically heterogeneic.
B) incompletely penetrant, variably expressive, and genetically heterogeneic.
C) completely penetrant, invariably expressive, and not genetically heterogeneic.
D) pleiotropic and genetically heterogeneic

Question 36

An offspring of parents whose genotypes are Aa and Aa may be

A) only Aa.
B) AA or aa.
C) AA, Aa, or aa.
D) only aa.

Question 37

Antonio is colorblind. His partner Emilia is not colorblind nor is she a carrier (heterozygote) for colorblindness. The offspring of this couple would

A) be sons with colorblindness and daughters with color vision.
B) be colorblind daughters and sons with normal color vision.
C) all be colorblind.
D) all have normal color vision.

Question 38

Gender determination for males reflects expression of

A) the SRY gene but not the Wnt4 gene.
B) the Wnt4 gene but not the SRY gene.
C) both the SRY and Wnt4 genes.
D) the entire Y chromosome.

Question 39

In genomic imprinting,

A) genes on the Y chromosome are only expressed in males.
B) children copy their parents' behavior.
C) the same allele has a different effect if inherited from the mother or father.
D) a trait affects a structure found only in one sex.

Question 40

Which of the following chromosomal abnormalities most severely affect a fetus?

A) XXX
B) Monosomy for a large autosome
C) Trisomy 21
D) XXY

Question 41

Genes have multiple alleles that differ in DNA sequence because a gene consists of many nucleotides, each of which can be any of four types.

Question 42

A human cell that has 69 chromosomes is

A) aneuploid.
B) triploid.
C) diploid.
D) euploid.

Question 43

The human genome contains millions of different genes.

Question 44

Most of the DNA in the human genome encodes protein.

Question 45

We can predict the likelihood of a particular inherited trait occurring in a particular family member by consulting the ways that genes are transmitted on chromosomes.

Question 46

Genetic information passes from protein to RNA to DNA.

Question 47

Gene expression profiling

A) detects the mRNAs present in a particular cell type under particular conditions.
B) detects the mutations that a person has inherited.
C) is a chart of chromosomes in specific cell types.
D) is a size-order chart of chromosomes.

Question 48

The field of genetics deals only with disease.

Question 49

Genetics is the study of the inheritance of traits and their variability.

Question 50

A heterozygote has identical alleles of a gene and a homozygote has different alleles.

Question 51

The expression of an inherited trait is the genotype and the DNA sequence is the phenotype.

Question 52

Ultrasound and maternal serum marker tests are less informative than amniocentesis or chorionic villus sampling (CVS) in diagnosing trisomy 21 because

A) ultrasound and maternal serum markers check chromosomes, and CVS and amniocentesis do not.
B) ultrasound and maternal serum markers do not check chromosomes, and CVS and amniocentesis do.
C) maternal serum markers and amniocentesis check chromosomes, and ultrasound and CVS do not.
D) ultrasound and CVS check chromosomes, and maternal serum markers and amniocentesis do not.

Question 53

Genes determine all of our characteristics.

Question 54

During amniocentesis

A) a needle removes cells from the fetus.
B) a piece of the placenta is snipped off and examined for abnormal cells.
C) fetal fibroblasts in amniotic fluid are cultured and a karyotype constructed.
D) blood is removed from a woman's arm and fetal cells isolated and their chromosomes karyotyped.

Question 55

A human cell that has 47 chromosomes is

A) monosomic.
B) euploid.
C) polyploid.
D) trisomic.

Question 56

Which of the following prenatal tests is non-invasive?

A) Amniocentesis
B) Chorionic villi sampling
C) Ultrasound
D) Inserting a shunt into a fetus with water on the brain

Question 57

If a Y-bearing sperm fertilizes an XX egg, the resulting individual would be

A) an XX female.
B) an XY male.
C) a male with XXY syndrome.
D) a female with XXY syndrome.

Question 58

A baby has three copies of each chromosome in every cell. She is

A) euploid.
B) aneuploid.
C) diploid.
D) polyploid.

Question 59

Chromosomes carry genes and genes carry genomes.

Question 60

Gametes pass genetic information from generation to generation.

Question 61

A multifactorial trait is determined by many environmental factors, but not necessarily genetic influences.

Question 62

People with aneuploid sex chromosomes are more severely affected than people with aneuploid autosomes.

Question 63

A recessive allele masks the effect of a dominant allele.

Question 64

A human male is hemizygous for genes on the X chromosome because he has two copies of that chromosome.

Question 65

An inverted bell-shaped curve represents the distribution of phenotypes of a multifactorial trait in a population.

Question 66

In genomic imprinting, the sex of a parent transmitting an allele is important in the phenotype of the offspring.

Question 67

The muscle disorder myotonic dystrophy can be caused by different genes, on different chromosomes. This means that the condition is genetically heterogeneic.

Question 68

Freckles are a phenotype and the allele combination that causes a clotting disorder is a genotype.

Question 69

Absence of the SRY gene and expression of the Wnt4 gene are necessary for female reproductive structures to develop in an embryo and fetus.

Question 70

Chromosome abnormalities include having a number other than 46, a chromosome that has an inverted sequence, and different chromosome types that exchange parts.

Question 71

In incomplete dominance, the phenotype of a heterozygote is in between that of either homozygote.

Question 72

Beard growth is a sex-influenced trait.

Question 73

Variable expressivity and pleiotropy can account for a disease that produces different intensities of symptoms or different symptoms among individuals.

Question 74

An autosomal dominant condition in a family will disappear if in any generation no one inherits the disease.

Question 75

A disorder that skips generations, affects both sexes, and is transmitted by parents who either have the condition or carry it is autosomal recessive.

Question 76

Janet is homozygous dominant for the wild-type allele of the gene that when mutant causes cystic fibrosis. Her brother Henry is a heterozygote. They both do not have the disease cystic fibrosis.

Question 77

A pedigree is a chart that aligns chromosome pairs by size.

Question 78

An autosomal condition affects only males.

Question 79

A genotype that does not affect everyone who inherits it is completely penetrant.

Question 80

A trait determined by more than one gene is polygenic.