Question 1

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

Accepted Answer

Cross C (AaBb × aabb) will result in a 1:1:1:1 genotypic ratio in the offspring because each parent contributes alleles that can combine to produce four different genotypes (AaBb, Aabb, aaBb, aabb) in equal proportions, assuming independent assortment of the A and B genes.

Question 2

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

Accepted Answer

All offspring from this cross will be heterozygous (Bb), as the homozygous black guinea pig (bb) can only pass on the b allele, and the homozygous brown guinea pig (BB) can only pass on the B allele.

Question 3

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

Accepted Answer

A vertical pattern of inheritance in a pedigree indicates a rare dominant trait that is being inherited from one generation to the next without skipping any generations.

Question 4

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

Accepted Answer

The purple plant must be homozygous dominant (AABB) to produce only purple offspring. The colorless plant must be homozygous recessive (aabb) to only produce colorless offspring. The F₁ generation (all-purple) must be heterozygous (AaBb) since they are producing the purple pigment. When the F₁ generation is crossed, we can use a Punnett square to determine the potential genotypes and phenotypes of the offspring: | | AB | Ab | aB | ab | |---|----|----|----|----| | AB| AABB|AABb|AaBB|AaBb| | Ab|AABb|AAbb|AaBb|Aabb| | aB|AaBB|AaBb|aaBB|aaBb| | ab|AaBb|Aabb|aaBb|aabb| From this, we can see that 3 out of 4 potential offspring genotypes result in purple offspring (AABB, AABb, and AaBB). Therefore, the parents must have been heterozygous (AaBb × AaBb) to produce the 775 purple, 200 red, and 65 colorless offspring in the F₂ generation.

Question 5

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

Accepted Answer

The process described is self-fertilization, where the egg and pollen come from the same plant to produce a zygote. Cross-pollination would involve pollen from a different plant, outcrossing refers to mating between individuals that are not closely related, recombination refers to the reshuffling of genetic material during meiosis, and trans-pollination is not a commonly used scientific term.

Question 6

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.

Accepted Answer

In a dihybrid cross AABB × aabb, the F1 generation will all be AaBb. When these F1 individuals are crossed (AaBb × AaBb), the F2 generation will have a 1:2:1 ratio for each gene. The proportion of offspring that are heterozygous for both genes (AaBb) is 1/4.

Question 7

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

Accepted Answer

Artificial selection refers to the deliberate breeding of plants or animals with desirable traits by humans. This allows the control over the genetic makeup of the offspring and can result in the development of new breeds or varieties. This process is often used in agriculture and animal breeding, to produce crops and livestock that are more productive, disease-resistant, or have other useful characteristics.

Question 8

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

Accepted Answer

The answer of Rosy coloured eyes and forked bristles are...

Question 9

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

Accepted Answer

The answer of Which of the following is not a...

Question 10

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.

Accepted Answer

The diploid cell formed by the fertilization of the egg by the sperm during sexual reproduction is called a zygote. Zygote is formed when the haploid sperm cell fuses with the haploid egg cell resulting in a single-celled diploid zygote.

Question 11

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

Accepted Answer

Penetrance and expressivity can lead to deviations from expected Mendelian ratios because they involve the degree to which a particular genotype is expressed in the phenotype. Penetrance refers to the likelihood that a gene will be expressed at all, while expressivity measures the extent of expression among individuals with a given genotype. These variations can result in observed phenotypic ratios that differ from the classic Mendelian predictions.

Question 12

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

Accepted Answer

A phenotypic ratio of 1:2:1 indicates incomplete dominance, where the heterozygous phenotype is intermediate between the two homozygous phenotypes.

Question 13

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

Accepted Answer

Morgan is not known for being involved in the rediscovery of Mendel's work. Instead, he conducted his own experiments with the fruit fly Drosophila and laid the foundation for the science of genetics. Watson, on the other hand, is known for his work on the structure of DNA, which built on the discoveries of Mendel and other geneticists.

Question 14

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)

Accepted Answer

The F₁ plants all had a dwarfed phenotype, which means that the dwarf allele (d) is dominant over the tall allele (D). The F₂ consisted of 1,207 dwarf plants and 401 tall plants, which is a 3:1 ratio. This ratio is consistent with the expected ratio for a cross between two heterozygous parents (Dd). Therefore, the genotypes of the two parents must be Dd (dwarf) and dd (tall).

Question 15

An alternative form of a single gene is known as
A) parental.
B) dihybrid.
C) reciprocal.
D) allele.
E) recessive.

Accepted Answer

An alternative form of a single gene is known as an allele. Alleles are variations of a gene that occur at the same locus (position) on homologous chromosomes. They code for different versions of a characteristic, such as eye color or blood type. Therefore, allele is the correct choice as it directly defines the given term.

Question 16

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.

Accepted Answer

The cross AaBb × aabb will produce F1 offspring with the following genotypes:1/4 AABB1/4 AaBB1/4 AAbb1/4 aaBBTherefore, 1/4 of the F1 offspring will be heterozygous for both gene pairs.

Question 17

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

Accepted Answer

To calculate the probability of either all-dominant or all-recessive genotypes, we need to first determine the probability of each genotype:

- All-dominant: AABBccddEEFF
Probability of AaBbCcddEeFf x AaBbCcddEeFf => 1/4 x 1/4 = 1/16 (since each gene has two alleles and the cross is between heterozygotes).
- All-recessive: aabbccddeeff
Probability of aabbccddeeff x AaBbCcddEeFf => 1/16 x 1/16 = 1/256 (since each gene has two alleles and the cross is between two heterozygotes).

The probability of either all-dominant or all-recessive genotypes is the sum of these probabilities:

1/16 + 1/256 = 17/256

Simplifying this fraction we get 1/128, which is answer D.

Question 18

Which of the following diseases show pleiotropism?
A) albinism
B) muscular dystrophy
C) colour blindness
D) sickle cell anaemia
E) male pattern baldness

Accepted Answer

Sickle cell anaemia is an example of pleiotropism because it affects multiple traits or organs such as the blood cells, bone marrow, spleen, liver, and kidneys. Albinism, muscular dystrophy, colour blindness, and male pattern baldness are examples of single-gene disorders that do not show pleiotropism.

Question 19

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.

Accepted Answer

Epistasis is the interaction between non-allelic genes that results in the masking of expression of a phenotype. This occurs when one gene suppresses the expression of a phenotype caused by another gene.

Question 20

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

Accepted Answer

Pure-breeding lines are those that produce offspring carrying specific parental traits that remain constant from generation to generation, indicating that the parental traits are homozygous dominant or homozygous recessive.

Quiz 1: Mendels Principles of Heredity

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

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?

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

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

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.

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

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

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

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

Which of the following phenotypic ratios show incomplete dominance?

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

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.

An alternative form of a single gene is known as

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

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

Which of the following diseases show pleiotropism?

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

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