Deck 11: Mendelian Patterns of Inheritance

Question 1

If a pea plant shows a recessive phenotype,

A)the genotype may be TT or Tt.
B)the genotype may be Tt or tt.
C)the genotype can only be TT.
D)the genotype can only be tt.
E)the genotype may be TT,Tt,or tt.

Answer 1

D

Question 2

In a classic Mendelian monohybrid cross between a homozygous dominant parent and a homozygous recessive parent,which generation is always completely heterozygous?

A)F₁ generation
B)F₂ generation
C)F₃ generation
D)P generation

Answer 2

A

Question 3

During what stage of meiosis does independent assortment occur? What is segregation and when does it occur in meiosis? How do these processes affect the gametes formed during meiosis? Explain.

Answer 3

In metaphase I of meiosis,homologous chromosomes align in many different orientations along the metaphase plate.The law of independent assortment relates to this random alignment at the metaphase plate.During anaphase 1,the homologous pairs segregate (separate)into opposite daughter cells.The random alignment of the homologous pairs during metaphase I and their subsequent segregation results in gametes with many possible combinations of chromosomes and alleles.

Question 4

Which of the following is NOT a trait that is the result of,or is affected by,the interaction of more than one gene?

A)human skin color
B)cleft palate
C)height
D)sickle-cell anemia

Question 5

What aspect of Mendel's background gave him the necessary tools to discover the laws of inheritance?

A)He was a monk.
B)He was a teacher.
C)He lived in Austria.
D)He had studied mathematics and probability.
E)He corresponded with Charles Darwin.

Question 6

The F₂ offspring of a classic Mendelian monohybrid cross between homozygous dominant and homozygous recessive parents would produce the genotype(s)

A)AA and Aa.
B)Aa and aa.
C)AA,Aa,and aa.
D)AA only.
E)Aa only.

Question 7

Some plants fail to produce chlorophyll,and this trait appears to be recessive.Many plants also self-pollinate.If we locate a pea plant that is heterozygous for this trait,self-pollinate it and harvest seeds,what are the likely phenotypes of these seeds when they germinate?

A)All will be green with chlorophyll.
B)All will be white and lack chlorophyll.
C)About one-half will be green and one-half white.
D)About one-fourth will be white and three-fourths green.
E)About one-fourth will be green and three-fourths white.

Question 8

Which of the following crosses will NOT produce offspring with the recessive phenotype? Select all that apply.

A)TT × Tt
B)Tt × Tt
C)TT × TT
D)Tt × tt
E)tt × tt

Question 9

A range of genotypes and phenotypes occur in polygenic inheritance.Draw a graph that depicts this pattern of continuous variation in polygenic inheritance.

Question 10

Why did Mendel choose pea plants for his research?

A)Peas are easy to cultivate.
B)Pea plants have a short generation time.
C)Pea plants are self-pollinating but can be cross-fertilized easily.
D)Many true-breeding varieties were available.
E)All of these were important characteristics in Mendel's selection.

Question 11

The pedigree chart depicts the inheritance pattern of ________.Circles depict females and squares depict males.Colored shapes represent affected individuals (expressing a trait)and uncolored shapes are unaffected (do not express a trait).

A)an autosomal recessive characteristic with both parents being heterozygous
B)an autosomal dominant characteristic with both parents being homozygous dominant
C)an autosomal recessive characteristic with both parents being homozygous recessive
D)None.

Question 12

What are alleles?

A)genes for different traits,such as hair color or eye color
B)alternative forms of a gene for a single trait,such as blue eyes or brown eyes
C)the locations of genes on a chromosome
D)the recessive form of a gene
E)the dominant form of a gene

Question 13

Which of the following statements accurately describes Gregor Mendel?

A)He had a strong background in mathematics.
B)He was very deliberate and followed the scientific method closely while doing his research.
C)He kept very detailed records of his research.
D)He conducted many preliminary studies with various animals and plants.
E)All of the statements accurately describe Gregor Mendel.

Question 14

Women with an X-linked disorder could pass the genes for the disorder to ________,and men with an X-linked disorder could pass the genes for the disorder to ________.

A)only their daughters; only their daughters
B)both their daughters and sons; only their sons
C)both their daughters and sons; only their daughters
D)both their daughters and sons; their daughters and sons

Question 15

The offspring of a monohybrid testcross could have what possible genotype(s)?

A)AA and Aa
B)Aa and aa
C)AA,Aa,and aa
D)AA only
E)aa only

Question 16

What is the blending theory of inheritance?

A)Mendel's theory of how traits are passed from parent to offspring.
B)Darwin's theory of how traits are passed from the parent to the offspring.
C)The modern theory of how genetic information is passed from parents to offspring.
D)A theory that describes how offspring show traits intermediate between those of the parents.

Question 17

The most common lethal genetic disease among Caucasians is

A)neurofibromatosis.
B)Tay-Sachs disease.
C)phenylketonuria.
D)albinism.
E)cystic fibrosis.

Question 18

If an individual with a dominant phenotype is crossed with an individual with a recessive phenotype,4 of their 9 offspring show the recessive phenotype.What is the genotype of the first parent?

A)AA
B)Aa
C)aa
D)The answer cannot be determined from this information.

Question 19

Create a pedigree chart that depicts an inheritance pattern of an autosomal dominant characteristic.Use circles to depict females and squares to depict males.Colored shapes represent affected individuals (expressing a trait)and uncolored shapes are unaffected (do not express a trait).

Question 20

Which of the following statements is NOT true according to Mendel's law of segregation?

A)Each individual contains two factors for each trait.
B)One factor must be dominant and one factor recessive in each individual.
C)Factors separate from each other during gamete formation.
D)Each gamete contains one copy of each factor.
E)Fertilization restores the presence of two factors.

Question 21

In 1940,two researchers named Weiner and Landsteiner discovered that about 85 percent of the human population sampled possessed a blood cell protein that had been previously detected in Rhesus monkeys.This blood type was labeled Rh positive,and Rh⁺ was found to be dominant over the absence of the blood factor (Rh^-).Under normal Mendelian inheritance,which of the following statements is FALSE?

A)Two Rh⁺ parents could have an Rh^- child.
B)Two Rh^- parents could have an Rh⁺ child.
C)An Rh^- child would require that both parents be carriers of at least one Rh^- gene.
D)It is possible with just one pair of parents to have children where some siblings are Rh^- and some are Rh⁺.
E)All of the choices are false.

Question 22

If a woman is a carrier for the colorblind recessive allele and her husband is normal,what are their chances that their son will be color blind?

A)None since the father is normal.
B)50% since the mother is a carrier.
C)100% because the mother is a carrier.
D)None since he will be a carrier like his mother.

Question 23

If a human who is a tongue roller (T)and has unattached ear lobes (E)marries a person who cannot roll their tongue and has attached earlobes,could they produce an offspring that was also a non-tongue-roller with attached earlobes? What would be the genotype of the first parent? The second parent?

A)yes; TtEe; ttee
B)yes; TtEE; ttEe
C)no; TTEE; ttee
D)unable to determine from the information given

Question 24

The particulate theory of inheritance

A)preceded Mendel's research by a century.
B)was proposed by Mendel.
C)is based on particles or hereditary units we now call genes.
D)All of the choices are correct.
E)Two of the above choices are correct.

Question 25

Lethal genes (genes that result in the failure to develop a vital organ or metabolic pathway)are nearly always recessive.Animal breeders who discover a unique trait and selectively breed to increase the occurrence of that trait often encounter a noticeable increase in lethal genes.Why?

A)The lethal recessive gene may be incompletely dominant.
B)Spreading the gene among offspring of both sexes will increase the likelihood it will be sex-linked and expressed.
C)The selective-mating of closely related individuals,or inbreeding,increases the chances that two recessive genes will "meet" in offspring.
D)"Pleiotropy"-the gene that is being selected for this trait may have the second effect of being lethal.
E)"Epistasis"-selection for the desired trait may result in "uncovering" the lethal gene.

Question 26

The ability to roll the edges of the tongue upward in a U-shape is considered to be an inherited trait.The standard assumption is that tongue-rolling is a dominant allele at a single gene locus.Which of the following would cast doubt on this assumption? Select all that apply.

A)A student who can roll his tongue has both a mother and father who cannot.
B)In a large research study,the majority of tongue-rollers were male.
C)A research study with 1,000 participants reports that most non-tongue-rollers can learn to roll their tongues.
D)A student who cannot roll his tongue has both a mother and father who can.

Question 27

Unattached earlobes (EE or Ee)are described in the textbook as dominant over attached earlobes (ee).A couple both have unattached earlobes.Both notice that one of their parents on both sides has attached earlobes (ee).Therefore,they correctly assume that they are carriers for attached earlobes (Ee).The couple proceeds to have four children.

A)They can be certain that three will be heterozygous and one homozygous recessive.
B)If the first three are heterozygous,the fourth must be homozygous recessive.
C)The children must repeat the grandparents' genotype (Ee).
D)All children must have unattached earlobes since both parents possess the dominant gene for it.
E)Two heterozygous,one homozygous recessive,and one homozygous dominant is a likely outcome,but all heterozygous,or two,three,or all four homozygous are also possible.

Question 28

The reason why some individuals who inherit polydactyly (having an extra digit on the hand or feet)do not express the trait is due to

A)incomplete penetrance.
B)incomplete dominance.
C)gene linkage.
D)pleiotropy.
E)None of the answers are correct.

Question 29

Computer simulations are sometimes used to demonstrate the outcome of monohybrid fruit fly crosses,where a student can run generation after generation of fruit flies with 100 offspring produced each generation,half male and half female,and a 3-to-1 phenotype ratio (or 75 to 25)in the F₁ generation.Compared with real genetics results,

A)rarely would exactly 100 fly offspring be produced or survive.
B)an exact balance between males and females would be rare.
C)a precise 3-to-1 ratio would be uncommon.
D)All of the choices are true.

Question 30

An individual with blood type A marries an individual with blood type B.
A.What blood types could their offspring exhibit?
B.Provide the possible genotypes of parents and offspring produced.
C.What pattern of inheritance is this?

Question 31

In pea plants,the gene for round seeds (R)is dominant,and wrinkled seeds (r)is recessive.The endosperm of the pea is also either starchy,a dominant gene (S),or waxy (s).What can be said of a fully heterozygous,dihybrid cross?

A)Some offspring could be homozygous for both dominant genes.
B)Some offspring could be homozygous for both recessive genes.
C)Some offspring could be homozygous for one dominant gene such as round seed and homozygous recessive for the other recessive waxy gene.
D)All of these choices are impossible combinations in a dihybrid cross.
E)All of these choices are possible combinations in a dihybrid cross.

Question 32

If two parents have blood genotypes I^Ai and I^Bi,which of the following blood genotypes are possible in their children?

A)I^Ai and I^Bi only
B)I^Ai,I^Bi,and I^AI^B only
C)I^AI^A,I^BI^B,and I^AI^B only
D)I^Ai,I^Bi,and ii only
E)I^Ai,I^Bi,I^AI^B and ii

Question 33

If the probability of event A is 3/4 and the probability of event B is 1/4,then the probability of both A and B occurring at the same time is

A)3/4.
B)1/4.
C)1 or absolute certainty.
D)1/2.
E)3/16.

Question 34

Since each child of two heterozygous parents has a 50% chance of receiving a recessive trait from each parent,

A)if the first child is phenotypically recessive,then the next child must be phenotypically dominant.
B)if the first child is phenotypically recessive,then the next child has a 3/4 chance of being phenotypically recessive.
C)if the first child is phenotypically recessive,then the next child has a 1/2 chance of being phenotypically recessive.
D)no matter what the first child's phenotype,the next child will have a 1/4 chance of being phenotypically recessive.

Question 35

In a Punnett square,

A)all the possible types of sperm are lined up either horizontally or vertically.
B)all the possible types of eggs are lined up either horizontally or vertically.
C)the results show the offspring's expected genotypes.
D)All of the choices are correct.
E)Only two of the choices are correct.

Question 36

In what kind of classic Mendelian cross would you expect to find a ratio of 9:3:3:1 among the F₂ offspring?

A)monohybrid cross
B)dihybrid cross
C)testcross
D)None of the choices are correct.

Question 37

As many as 60% of people in malaria-infected regions of Africa have the sickle-cell allele,but only about 10% of the U.S.population of African ancestry carries the allele.Malaria remains a major disease in central Africa but has not been a serious problem in the U.S.for many generations.What is/are the reason(s)for the difference in the percentages and what is a reasonable statement about future percentages?

A)The presence of malaria in Africa maintains the advantage of the heterozygous sickle-cell trait,and the prevalence of malaria will likely continue to preserve the 60% rate.
B)The U.S.percentage may have always been somewhat lower due to immigration from nonmalaria regions,but changes in sites and rates of immigration could occur.
C)Lack of widespread malaria in the United States would have resulted in both homozygous and heterozygous carriers of sickle cell undergoing several generations of negative selection.We should expect this to continue unless innovative therapies give all individuals an equal chance of surviving and reproducing.
D)All of the choices are reasonable.

Question 38

If individuals exhibiting a dominant phenotype are crossed and produce only offspring with the dominant phenotype,which of the following could be the genotype of the parents?

A)Both are homozygous recessive.
B)One is heterozygous and one is homozygous dominant.
C)Both are homozygous dominant.
D)Both are heterozygous.
E)Two of the options may be correct.

Question 39

Haiti is settled by peoples of both African and European ancestry.A young couple,both with mixed ancestry,marry and have several children.The children,who all have equal exposure to sunlight,vary widely in the amount of skin melanin.One child is lighter than both parents,and one is darker.The simple explanation for this is

A)epistasis.
B)multiple alleles are available for the one chromosomal locus that governs skin color.
C)the environment influenced the phenotypes of the children.
D)polygenic inheritance.
E)gene linkage.

Question 40

A testcross involves an individual with the dominant phenotype but unknown genotype being crossed with an individual that has a(n)________ genotype.

A)homozygous dominant
B)heterozygous dominant
C)homozygous recessive
D)Any of the choices.

Question 41

Which of the following disorders is not a X-linked trait?

A)hemophilia
B)muscular dystrophy
C)adrenoleukodystrophy
D)All of these are X-linked disorders.

Question 42

If an individual is heterozygous for a particular trait,the gametes that individual produces will contain 3/4 dominant and 1/4 recessive alleles.

Question 43

Black and brown guinea pigs are bred together.Assuming their color is determined by one gene,and that there is a dominant and a recessive allele,how would you determine which allele is dominant? How could you determine the genotypes of the parents? Explain.

Question 44

Which statement about the blending concept of inheritance is correct?

A)A cross between a tall man and a short woman would always produce children of medium height.
B)A cross between a tall man and a short woman can produce some children that are tall while others are short.
C)A cross between a tall man and a short woman produces tall children who can then produce short grandchildren.
D)Genetic material is unstable which accounts for such a wide diversity in our offspring.

Question 45

If black fur is produced by a recessive allele,which genotype is most likely to produce a black individual?

A)bb
B)BB
C)Bb
D)Cb

Question 46

In a case of incomplete dominance,the phenotypic ratio of the F₂ generation is the same as the genotypic ratio.

Question 47

A single,simple,recessively inherited mutation inactivates the enzyme that converts phenylalanine to tyrosine.Homozygous recessive individuals possess an excessive amount of phenylalanine and a deficiency of tyrosine.Additionally,these individuals may be mentally deficient,have abnormally light hair and abnormally light skin color.This disorder is an example of

A)incomplete penetrance.
B)incomplete dominance.
C)polygenic inheritance.
D)pleiotropy.

Question 48

What is pleiotropy?

A)A single mutant gene affects two or more distinct and seemingly unrelated traits.
B)A single mutant gene affects one trait.
C)Two mutant genes affect one trait.
D)A single mutant gene has no effect on an individual's phenotype.

Question 49

Which allele combination represents a heterozygous individual?

A)aa
B)AA
C)Aa
D)None of these represent a heterozygous individual.

Question 50

During Mendel's pea plants experiment,he discovered that the trait for tallness is dominant to that of shortness.Which of the following statements is correct?

A)Tall = TT or Tt while short = tt
B)Tall = TT or tt while short = Tt
C)Tall = tt while short = TT or Tt
D)None of these statements are correct.

Question 51

Upon examination,a person is found to only have half the normal number of LDL-cholesterol receptors.Which of the following best explains this?

A)pleiotropic inheritance
B)polygenic inheritance
C)incomplete dominance
D)X-linked inheritance

Question 52

When crossing a true-breeding red snapdragon flower with a true-breeding white flower of the same species,all offspring are pink.This would seem to support the pre-Mendel view that inheritance is a blending of parental traits.However,Mendel and conventional wisdom agree that "blending" of parental traits is not correct and that particles of inheritance are actually involved.Which of the following statements supports the idea of particulate inheritance? Select all that apply.

A)Two parents that show the incompletely dominant phenotype produce some offspring that are red and some that are white.
B)Over many generations of crossing individuals with the incompletely dominant phenotype,all the progeny are pink.
C)There is no way to directly prove that incomplete dominance is not a case of blending.
D)In meiosis,alleles of different genes assort independently of each other during gamete formation.

Question 53

Each gamete carries one factor,now called an allele,for each inherited trait.

Question 54

What is the blending theory of inheritance? How did Mendel disprove this theory?

Question 55

Which allele combination represents a homozygous dominant individual?

A)AA
B)Aa
C)aa
D)None of these are homozygous dominant individuals.

Question 56

If white eyes are produced by a recessive allele,what is the likely genotype of a white-eyed individual?

A)rr
B)Rr
C)RR
D)RB

Question 57

Polygenic traits such as height or weight are often influenced by the environment of the organism.

Question 58

When an individual of African descent marries and has children with an individual of European descent,their children often have a mid-shade of skin color,but they could also have a light shade or a dark shade.This can best be described as

A)X-linked inheritance.
B)polygenic inheritance.
C)pleiotropic inheritance.
D)the dominance of the gene for dark skin tone.

Question 59

Which is associated with the inability to produce factor VIII in the blood?

A)Williams syndrome
B)trisomy 21
C)color blindness
D)hemophilia A
E)Duchenne muscular dystrophy

Question 60

Cystic fibrosis and phenylketonuria are common autosomal dominant disorders.

Question 61

Which of the following is NOT part of Mendel's law of segregation?

A)Each individual has two factors for each trait.
B)The factors segregate during meiosis.
C)Each gamete will carry two factors for a trait.
D)Fertilization gives the offspring two factors for each trait.