Deck 24: Genetics and Genomics

Question 1

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 1

B

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

Observing a karyotype for a fetus, an obstetrician notices that for the 16ᵗʰ chromosome, there are 3 structures shown. What sort of chromosomal abnormality does this fetus have?

A)A monosomy
B)Incomplete dominance
C)A trisomy
D)Polyploidy

Answer 3

C

Question 4

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 5

An allele that masks the effect of another is

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

Question 6

Studies have indicated a genetic link between a chromosome abnormality and acute myeloid leukemia, a deadly cancer affecting white blood cell production. Many sufferers of the cancer also possess monosomy 7, which is passed along generations in their families and also corresponds with the incidence of cancer in its members. What would you notice on a karyotype taken from a family with a trend of genetic-linked acute myeloid leukemia?

A)Seven copies of each chromosome
B)Three copies of each chromosome
C)Only one copy each of the 7ᵗʰ and the 21ˢᵗ chromosome
D)Only one copy of the 7ᵗʰ 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 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 9

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 10

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 11

Different alleles of the same gene are said to be

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

Question 12

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 13

Your family has a strong genetic predisposition to abnormal blood clotting and deep vein thrombosis. How does this affect or determine your chances of suffering from the same conditions? 

A)You are guaranteed to experience blood clots and deep vein thrombosis, as the genes producing such conditions are definitely in your genome and will become active at some point.
B)You don't have to worry about these conditions because genetic predisposition doesn't at all affect your chances of developing these conditions if you exercise regularly and eat healthy foods.
C)You must expect to die from such conditions if more than 4 or 5 of your relatives have also died from them, as medicine does not yet know how to stop genetic conditions from taking their course.
D)You have a higher risk of suffering from these conditions, but you can still take preventative steps to reduce the risk if you know about the genetic predisposition. You are not absolutely guaranteed to suffer deep vein thrombosis because environmental factors can be changed.

Question 14

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 15

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% normal and 25% albino; genotypes:75% heterozygous and 25% homozygous.
D)phenotypes:all albino; genotypes:50% heterozygous and 50% homozygous recessive.

Question 16

Genetics is the study of

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

Question 17

Identical alleles are said to be

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

Question 18

The human genome consists of

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

Question 19

How alike are our genomes?

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

Question 20

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 21

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 22

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 blood clotting. 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 23

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 24

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 25

A couple is trying to calculate the chance of genetic traits in their potential offspring. From family history, the man presumes he is heterozygous for the height gene via the "tall" allele (T). His partner is short in stature, so she believes she is homozygous for the height gene via the "short" allele (t). Assuming the "tall" allele is completely dominant, what is the chance that their offspring would be tall in stature? 

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

Question 26

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 27

An example of a sex-influenced trait is

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

Question 28

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

A)AA.
B)Aa.
C)aa.
D)None of the answer choices are correct.

Question 29

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 30

An allele that is not expressed in the heterozygous condition is

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

Question 31

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 32

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 33

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 34

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 35

A multifactorial trait is determined by

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

Question 36

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

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

Question 37

Phenylketonuria (PKU)is a genetic disease caused by mutation of the PAH gene, which normally produces the enzyme phenylalanine hydroxase. This enzyme is essential for the conversion of the amino acid phenylalanine into tyrosine. Without the enzyme, phenylalanine builds up in the blood and tissues of various body regions. It can produce severe skin discolorations and foul odor, but also intellectual disabilities and behavioral problems. Some people may experience only one type of PKU symptoms and not the others. PKU is an example of

A)genetic heterogeneity.
B)complete penetrance.
C)incomplete penetrance.
D)pleiotropy.

Question 38

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

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

Question 39

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 40

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 41

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

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

Question 42

A human cell that has 47 chromosomes is

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

Question 43

Chromosomes carry genes and genes carry genomes.

Question 44

A human cell with 46 chromosomes is

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

Question 45

The human genome contains millions of different genes.

Question 46

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

Question 47

A human cell that has 69 chromosomes is

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

Question 48

Genetic information passes from protein to RNA to DNA.

Question 49

Gametes pass genetic information from generation to generation.

Question 50

Down syndrome is caused by

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

Question 51

The field of genetics deals only with disease.

Question 52

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 53

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 54

A woman wishes to have her unborn child tested for genetic disorders and see a full karyotype of her child's genome but does not want to have the amniotic sac punctured to retrieve samples. Which of the following tests will give the most accurate and thorough examination of the fetal genome without puncturing the amniotic sac to retrieve fetal DNA?

A)Amniocentesis
B)Chorionic villus sampling
C)Ultrasonography
D)Maternal serum marker screening

Question 55

The chemical groups that binds to DNA causing genomic imprinting are

A)methyl groups.
B)RNA molecules.
C)transcription factors.
D)amino acids.

Question 56

Genes determine all of our characteristics.

Question 57

A woman insists on an ultrasound and a maternal serum marker test to check for Trisomy 21 in her unborn child because she only wants to use non-invasive methods. Her obstetrician will

A)follow the procedures she wants, because ultrasound and maternal serum markers check chromosomes while CVS and amniocentesis do not.
B)heavily advise against this decision, because ultrasound and maternal serum markers do not check chromosomes while CVS and amniocentesis do.
C)allow the maternal serum marker test but still recommend amniocentesis, because maternal serum markers and amniocentesis check chromosomes while ultrasound and CVS do not.
D)allow the ultrasound but still recommend CVS, because ultrasound and CVS check chromosomes while maternal serum markers and amniocentesis do not.

Question 58

After receiving a karyotype of a fetus, it is discovered that it has Klinefelter's syndrome. What does this designation indicate?

A)The fetus is female and resulted from one of the gametes having an extra X chromosome.
B)The fetus is an XY male.
C)The fetus is male and the result of a Y-bearing sperm fertilizing an XX egg.
D)The fetus is female and the result of only one gamete possessing an X chromosome.

Question 59

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 60

Most of the DNA in the human genome encodes protein.

Question 61

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 62

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

Question 63

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

Question 64

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

Question 65

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

Question 66

A recessive allele masks the effect of a dominant allele.

Question 67

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

Question 68

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

Question 69

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

Question 70

An autosomal condition affects only males.

Question 71

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

Question 72

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 73

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

Question 74

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

Question 75

A trait determined by more than one gene is polygenic.

Question 76

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 77

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

Question 78

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 79

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

Question 80

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.