Deck 1: Mendels Principles of Heredity

Question 1

Which of the following terms is not a type of mating cross?

A) reciprocal
B) testcross
C) monohybrid
D) dihybrid
E) dominant

Answer 1

E

Question 2

A dominant trait,Huntington disease,causes severe neural/brain damage at approximately age 40.The gene that causes this disease is not located on the sex chromosomes.A female whose mother has Huntington disease marries a male whose parents are normal.It is not known if the female has the disease.Assuming the female's mother was a heterozygote,and her father was normal,what is the probability that their firstborn will inherit the gene that causes Huntington disease?

A) 25%
B) 50%
C) 75%
D) 100%
E) 0%

Answer 2

A

Question 3

Assume that in guinea pigs,dark brown fur (B)is dominant to black fur (b).If you mate a black guinea pig with a homozygous brown guinea pig,what proportion of the progeny will be homozygous?

A) none
B) 1/4
C) 1/2
D) 3/4
E) all

Answer 3

A

Question 4

In some genetically engineered corn plants,a dominant gene (BT)produces a protein that is lethal to certain flying insect pests that eat the corn plants.It was also found that the pollen could cause death in some flying insects.If the corn plant is heterozygous for BT,what proportion of the pollen would carry the dominant gene?

A) all pollen
B) 1/2
C) 1/3
D) 1/4
E) 1/8

Question 5

______ is/are a cross(es)between parents that differ in only one trait.

A) Self-fertilization
B) Cross fertilization
C) Monohybrid crosses
D) Artificial selection
E) Reciprocal crosses

Question 6

In a dihybrid cross AAbb × aaBB,what proportion of the F₂ offspring is expected to be homozygotic for at least one gene?

A) 1/4
B) 1/2
C) 3/4
D) All are homozygotes.
E) None are homozygotes.

Question 7

If the parents of a family already have two boys,what is the probability that the next two offspring will be girls?

A) 1
B) 1/2
C) 1/3
D) 1/4
E) 1/8

Question 8

A phenotype reflecting a new combination of genes occurring during gamete formation is called

A) a recombinant type.
B) an independent assortment.
C) heterozygous.
D) homozygous.
E) a multihybrid cross.

Question 9

A _____________ is a cross between an unknown and a homozygous recessive.

A) testcross
B) dihybrid
C) monohybrid
D) backcross
E) controlled

Question 10

Sickle cell anaemia is a recessive trait in humans.The gene that causes this disease is not located on the sex chromosomes.In a cross between a father who has sickle cell anaemia and a mother who is heterozygous for the gene,what is the probability that their first three children will have the normal phenotype?

A) 1/4
B) 1/2
C) none
D) 1/8
E) 1/16 will be albino

Question 11

The actual alleles present in an individual make up the individual's

A) recombinant types.
B) zygote.
C) dominant allele.
D) allele.
E) genotype.

Question 12

In the dihybrid cross AaBb × aabb,what proportion of individuals are expected to be homozygotic for both genes in the F₁ generation?

A) 1/4
B) 1/2
C) 3/4
D) All are homozygotes.
E) None are homozygotes.

Question 13

A rare recessive trait in a pedigree is indicated by which pattern of inheritance?

A) vertical
B) horizontal
C) diagonal
D) both vertical and horizontal
E) father to daughter inheritance

Question 14

Assume that in guinea pigs,dark brown fur (B)is dominant to black fur (b).If you mate a homozygous black guinea pig with a heterozygous brown guinea pig,what proportion of the progeny will be black?

A) none
B) 1/4
C) 1/2
D) 3/4
E) all

Question 15

In a monohybrid cross AA × aa,what proportion of homozygotes is expected among the F₂ offspring?

A) 1/4
B) 1/2
C) 3/4
D) All are homozygotes.
E) None are homozygotes.

Question 16

Assuming independent assortment,which of the crosses below will produce a 1:1 phenotypic ratio among the F₁ progeny?

A) AABB × aabb
B) AaBb × AaBb
C) AaBb × aabb
D) AaBB × aaBB
E) AAbb × aaBB

Question 17

Suppose that in plants,smooth seeds (S)are dominant to wrinkled seeds (s)and tall plants (T)are dominant to short plants (t).A tall plant with smooth seeds was backcrossed to a parent that was short and wrinkled.Assuming independent assortment,what proportion of the progeny is expected to be homozygous for short and wrinkled?

A) 1/2
B) 1/4
C) 1/8
D) 1/16
E) 0

Question 18

The first generation of offspring from the parents is called

A) P_.
B) F_1.
C) F_2.
D) testcross.
E) backcross.

Question 19

An allele that expresses its phenotype even when heterozygous with a recessive allele is termed

A) recessive.
B) recombinant.
C) dominant.
D) D)parental.
E) independent.

Question 20

If an individual has 10 gene pairs,how many different gametes can be formed if three of the gene pairs are homozygous and the remaining seven gene pairs are heterozygous?

A) 49
B) 100
C) 128
D) 1024
E) 131,072

Question 21

Which of the crosses listed below will give a 1:1:1:1 genotypic ratio in the F₁ generation? Assume independent assortment.

A) AABB × aabb
B) AaBb × AaBb
C) AaBb × aabb
D) AaBB × aaBB
E) AAbb × aaBB

Question 22

Assume that in guinea pigs,dark brown fur (B)is dominant to black fur (b).If you mate a homozygous black guinea pig with a homozygous brown guinea pig,what proportion of the progeny will be heterozygous?

A) none
B) 1/4
C) 1/2
D) 3/4
E) all

Question 23

What does a vertical pattern of inheritance in a pedigree likely indicate?

A) rare recessive trait
B) rare dominant trait
C) mulitgenic inheritance
D) environmental impact
E) common recessive trait

Question 24

In some plants,a purple pigment is synthesized from a colourless precursor.In a cross between two plants,one purple and the other colourless,an F₁ generation was produced that was all-purple.The F₂ produced from the F₁ had 775 purple,200 red,and 65 colourless.What is the genotype of the parents?

A) AABB × AABB
B) AABB × aabb
C) aabb × aabb
D) aaBB × aabb
E) AAbb × aabb

Question 25

When both egg and pollen from the same plant produce a zygote,the process is called

A) cross-pollination
B) outcrossing
C) self-fertilization
D) recombination
E) trans-pollination

Question 26

In a dihybrid cross for which the parental cross is AABB × aabb,what proportion of F₂ offspring will be heterozygous for both genes? Assume independent assortment.

A) 1/4
B) 1/2
C) 3/4
D) All are heterozygotes.
E) None are heterozygotes.

Question 27

The purposeful control over mating by choice of parents for the next generation is called

A) artificial selection
B) natural selection
C) mutation
D) evolution
E) random selection

Question 28

Rosy coloured eyes and forked bristles are unlinked,recessive traits in Drosophila.A rosy-eyed Drosophila with wild-type bristles was crossed with a forked Drosophila with wild-type eyes.All of the F₁ were phenotypically wild-type for both traits,whereas the F₂ consisted of 306 wild-type,94 rosy-eyed,102 fork-bristled,and 33 forked-bristled and rosy-eyed flies.Infer the genotypes of the parents.

A) rrff,RRFF
B) Rrff,rrFf
C) RRFF,RRFF
D) rrff,rrff
E) RRff,rrFF

Question 29

Which of the following is not a phenotypic description of allele interactions affecting the expression of traits?

A) incomplete dominance
B) codominance
C) polymorphic
D) multifactorial
E) pleiotropic

Question 30

The diploid cell formed by the fertilization of the egg by the sperm during sexual reproduction is a

A) reciprocal.
B) zygote.
C) dihybrid.
D) gamete.
E) monohybrid.

Question 31

A deviation from normal Mendelian ratios,which may be resolved by counting and/or controlled crosses,is seen in which of the following terms?

A) pleiotropy
B) codominance
C) incomplete dominance
D) complete dominance
E) penetrance and expressivity

Question 32

Which of the following phenotypic ratios show incomplete dominance?

A) 2:1
B) 3:1
C) 1:2:1
D) 1:1
E) 4:1

Question 33

Which of the following was not involved in the rediscovery of Mendel's work?

A) Correns
B) de Vries
C) Tschermak
D) Morgan
E) Watson

Question 34

After a cross between two corn plants,the F₁ plants all had a dwarfed phenotype.The F₂ consisted of 1,207 dwarf plants and 401 tall plants.Identify the phenotypes and genotypes of the two parents.

A) DD (dwarf),dd (tall)
B) DD (tall),dd (dwarf)
C) dd (dwarf),dd (tall)
D) DD (dwarf),DD (tall)
E) dd (dwarf),Dd (tall)

Question 35

An alternative form of a single gene is known as

A) parental.
B) dihybrid.
C) reciprocal.
D) allele.
E) recessive.

Question 36

For the cross AaBb × aabb,what proportion of F₁ offspring will be heterozygous for both gene pairs? Assume independent assortment.

A) 1/4
B) 1/2
C) 3/4
D) All are heterozygotes.
E) None are heterozygotes.

Question 37

Calculate the probability of either all-dominant or all-recessive genotypes for the alleles A,B,E,and F in the following cross: AaBbccddEeFf× AaBbCcddEeFf

A) 1/32
B) 1/16
C) 1/64
D) 1/128
E) 1/256

Question 38

Which of the following diseases show pleiotropism?

A) albinism
B) muscular dystrophy
C) colour blindness
D) sickle cell anaemia
E) male pattern baldness

Question 39

An interaction between non-allelic genes that results in the masking of expression of a phenotype is

A) epistasis.
B) epigenetic.
C) dominance.
D) codominance.
E) incomplete dominance.

Question 40

Lines that produce offspring carrying specific parental traits that remain constant from generation to generation are called

A) maternal
B) indeterminate
C) heterozygous
D) pure-breeding
E) wild-type

Question 41

A person who has type O blood has

A) anti-A antibodies.
B) anti-B antibodies.
C) anti-AB antibodies.
D) both anti-A and -B antibodies.
E) no surface antigens.

Question 42

Which of the following phenotypic ratios show independent assortment?

A) 9:3:3:1
B) 9:7
C) 9:3:4
D) 13:3
E) All of the choices are correct.

Question 43

If two or more forms of the same gene exist,the different forms are called

A) incomplete dominance.
B) penetrance and expressivity.
C) pleiotropic.
D) alleles.
E) dihybrid.

Question 44

The phenotypic ratio 3:1 may indicate

A) complete dominance.
B) codominance.
C) epistasis.
D) incomplete dominance.
E) codominance and epistasis.

Question 45

When the same gene is related to respiratory problems and sterility,it can be described as

A) pleiotropy.
B) codominance.
C) incomplete dominance.
D) complete dominance.
E) penetrance and expressivity.

Question 46

Which of these is not an example of a continuous trait?

A) age at death
B) occurrence of phenylketonuria (PKU)
C) human skin colour
D) birth weight of mice
E) plant height

Question 47

The blood groups A,B,and O are different types of

A) incomplete dominance.
B) penetrance and expressivity.
C) pleiotropy.
D) alleles.
E) heterozygotes.

Question 48

The phenotypic ratio 9:3:4 may indicate

A) complete dominance.
B) codominance.
C) epistasis.
D) recessive lethal.
E) codominance and epistasis.

Question 49

Temperature sensitive (ts)alleles of the Drosophila shibire gene were isolated by David Suzuki.Under permissive conditions,what is the phenotype of flies homozygous for the ts alleles?

A) lethal
B) conditional on other factors
C) indistinguishablefrom wild-type
D) continuously variable
E) co-dominant

Question 50

Which of the following ratios indicates a lethal gene?

A) 2:1
B) 3:1
C) 1:2:1
D) 1:1
E) 4:1

Question 51

Which of the following ratios demonstrate gene interaction?

A) 2:1
B) 3:1
C) 1:2:1
D) 9:3:4
E) 1:3

Question 52

The phenotypic ratio 1:2:1 may indicate

A) complete dominance.
B) codominance.
C) epistasis.
D) recessive lethal.
E) codominance and epistasis.

Question 53

People may inherit a specific genotype that predisposes them to cancer.However,not everyone with this genotype develops cancer;the occurrence of cancer in these individuals is dependent on environment.This is an example of:

A) epistasis
B) incomplete penetrance
C) variable expressivity
D) incomplete dominance
E) complementation

Question 54

Which of the following ratios show codominance?

A) 2:1
B) 3:1
C) 1:2:1
D) 1:1
E) 4:1

Question 55

A _____________ results whenever the nucleotide sequence is changed.

A) phenotype
B) genotype
C) mutation
D) trait
E) character

Question 56

Which of the following monohybrid ratios can describe incomplete dominance and codominance?

A) 2:1
B) 3:1
C) 1:3
D) 1:2:1
E) 4:1

Question 57

Another name for a normal gene is

A) wild-type.
B) pleiotropy.
C) dominant.
D) codominant.
E) recessive.

Question 58

The phenotypic ratio 2:1 may indicate

A) complete dominance.
B) codominance.
C) epistasis.
D) recessive lethal.
E) codominance and epistasis.

Question 59

The blood groups A,B,and O show

A) complete dominance.
B) recessiveness.
C) codominance.
D) complete dominance,recessiveness,and codominance.
E) None of the choices are correct.

Question 60

The phenotypic ratio 9:7 may indicate

A) complete dominance.
B) codominance.
C) epistasis.
D) recessive lethal.
E) complementary gene action.

Question 61

The mating of parents with antagonistic traits produces hybrids.

Question 62

Which of the following statements about continuous traits is not true?

A) they do not obey Mendel's laws
B) they are called complex traits
C) they are also called quantitative traits
D) they are relevant to medicine
E) they are relevant to agriculture

Question 63

At fertilization,in the mating of dihybrids,four different kinds of eggs can combine with four different kinds of pollen,producing a total of sixteen different genotypes.

Question 64

The Punnett square was introduced in 1906 by Reginald Punnett and provides a simple and convenient method of tracking possible combinations of gametes that might be produced in a given cross.

Question 65

Which of the following is not useful in a complementation test?

A) recessive alleles
B) sexual reproduction
C) pure breeding lines
D) F₁ progeny
E) alleles dominant to wild-type

Question 66

Using the product rule,one would calculate the probability of parents having six children who are all boys as (½)⁶.

Question 67

The sum rule states that the probability of both of two mutually exclusive events occurring is the sum of their individual probabilities.

Question 68

Wild-type pea flowers are purple.You find spontaneous,white-flowered mutants growing nearby in five different locations (numbered a-e).You establish pure breeding lines of each and perform crosses between them,and record the F₁ phenotype in the table below.Based on the data in the table,how many different genes in the pathway for purple flowers have been identified by mutation? $$\begin{array} { | l | l | l | l | l | l | } \hline & \text { a } & \text { b } & \text { c } & \text { d } & \text { e } \\\hline \text { a } & \text { white } & \text { purple } & \text { purple } & \text { white } & \text { purple } \\\hline \text { b } & \text { purple } & \text { white } & \text { purple } & \text { purple } & \text { purple } \\\hline \text { c } & \text { purple } & \text { purple } & \text { white } & \text { purple } & \text { white } \\\hline \text { d } & \text { white } & \text { purple } & \text { purple } & \text { white } & \text { purple } \\\hline \text { e } & \text { purple } & \text { purple } & \text { white } & \text { purple } & \text { white } \\\hline\end{array}$$

A) 1
B) 2
C) 3
D) 4
E) 5

Question 69

An individual can be a heterozygote for one trait and a homozygote for another.

Question 70

How does penetrance differ from expressivity?

A) expressivity is dependent on environment;penetrance is not
B) expressivity is qualitative (presence or absence);penetrance is quantitative
C) penetrance involves multiple genes;expressivity involves a single gene
D) penetrance is qualitative (presence or absence);expressivity is quantitative
E) penetrance is dependent on environment;expressivity is not

Question 71

If two homozygous recessive mutants show the same phenotype,but are caused by mutations at different loci,what will be the phenotype ratio among their F₁ progeny?

A) 1 wild-type : 0 mutant
B) 1 wild-type : 2 mutant
C) 1 wild-type : 1 mutant
D) 2 wild-type : 1 mutant
E) 0 wild-type : 1 mutant

Question 72

If yellow and round phenotypes in peas are dominant,and pea shape and colour are each controlled by a single gene,you know the genotype of all peas that are green and wrinkled.

Question 73

Seeds of some lentils are speckled.A true breeding strain with small speckles is crossed with a true breeding strain with large speckles.All of the F1 progeny have both large and small speckles.Which of the following is true?

A) The trait is controlled by two genes and the alleles are co-dominant
B) The trait is controlled by one gene and the alleles are co-dominant
C) The trait is controlled by two genes and the alleles are incompletely dominant
D) The trait is controlled by one gene and the alleles are incompletely dominant
E) The trait is controlled by one gene and both alleles are dominant

Question 74

During gamete formation,different pairs of alleles on different chromosomes segregate independently of each other.

Question 75

Several alleles at several different loci all contribute additively to the same trait.Therefore,for this trait:

A) homozygotes cannot exist
B) heterozygotes cannot exist
C) only one phenotypic class is possible
D) only two phenotypic classes are possible
E) continuous variation may be observed

Question 76

A testcross is a cross between two heterozygotes.

Question 77

AA and Aa make red flowers,and aa makes white flowers.BB and Bb make tall plants,and bb makes short plants.What would be the expected ratios of phenotypes among the offspring of the cross of AaBb x aaBb? Note the genotypes in the cross carefully.Assume independent assortment of each gene.

A) 9 (red & tall): 3 (red & short): 3 (white & tall): 1 (white & short)
B) 3 (red & tall): 1 (white & tall)
C) 3 (red & tall): 1 (red & short): 3 (white & tall): 1 (white & short)
D) all (red & tall)
E) 1 (red & tall): 1 (red & short): 1 (white & tall): 1 (white & short)

Question 78

Dihybrid crosses helped reveal the law of independent assortment.

Question 79

If you know the phenotype and the dominance relation of the alleles you can predict the genotype.

Question 80

Mendel's law of segregation states that two alleles for each trait unite in a specific,predictable manner during gamete formation.