Biology Ch 8 Class 12 Variation and Genetics





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In birds the male is the homogametic sex. A male bird showing the recessive trait was mated with a female showing the dominant trait of a characteristic governed by a pair of alleles which are sex-linked. What is the probability that the male offspring will show the dominant trait?

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Mendel concluded that each organism has two hereditary factors for each trait, now called:

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Filial is a Latin word. It means

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Erythroblastosis foetalis occurs when:

NTS 2011
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D) Both mother and baby are Rh-positive

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In cats, the genes controlling coat-color are co-dominant (incompletely dominant) and are carried on the X chromosomes. When a black female was mated with a ginger male the resulting litter consisted of black male and tortoise-shell female kittens. What phenotypic ratio would be expected in the F2 generation?

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Linked genes with closer loci ______ Mendel’s law of independent assortment as they _____ assort independently.

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A man with blood group “A” marries a woman of blood group “B”. Both are heterozygous. What is the off-springs having phenotype “O”

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A pea plant has purple colored flowers (dominant trait). To check the genotype, which of the following cross is performed

NUMS 2018
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A pure breeding tall plant was crossed to dwarf plant. What would be probability of “Tt” genotype in F2

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A trait whose alleles are present in both males and females but prominent more in one sex than other is a:

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Which of the following characters of pea plant is dominant?

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A cross between F1 hybrids and either of parents is called:

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How many pairs of homologous chromosomes are present in Pisum sativum

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The law of dominance is illustrated in the garden pea by:

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If the seed is heterozygous yellow (Yy). In a test cross, what will be the probability of appearance of seed colors?

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If we cross round yellow seeded plant with green wrinkled seeded plants, what will be phenotypic ratio at F2 generation?

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The genes which do not follow law of independent assortment

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In the pea plants, the factors round and yellow seeds (RRYY) is dominant over wrinkled and green seeds (rryy). Keeping this in mind, identify the seed that has the genotype round and green.

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If we cross round (RR) seeded plants with wrinkled (rr) seed plant, and get F1 round seeded. In F2 generation, what will be genotypic ration of plants try Punnett square method?

NUMS 2019 Cancelled
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In which of the following cases, genotypic and phenotypic ratio will remain same in F2 generation

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______ are more common in human males than females.

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When both the alleles of a gene pair are same, the organism is said to be:

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How many genes control Rh blood group system?

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When phenotype of a heterozygote is in between the phenotypes of both the homozygous parents, it is called:

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Read the passage below to answer the question:

Haemophilia is a disorder in which blood fails to clot. Saad, a male haemophiliac, marries Sara, a normal woman and together they have four children, two boys (Ahmed and Ali) and two girls (Alia and Ayesha). None of the children display the symptoms of Haemophilia.

Ahmed, Ali, Ayesha, and Ali all marry normal individuals and have children. None of Ahmed’s or Ali’s children, male or female, display symptoms of haemophilia, but the sons of Alia and Ayesha display symptoms of haemophilia while the daughters of Alia and Ayesha do not.

Which of the following best explains the reason that Ahmed, Ali, Ayesha and Alia do not display symptoms of haemophilia, even though their father, Saad, is a haemophiliac.

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Red green colour blindness is a sex linked recessive trait. If a colour blind man marries a woman with normal vision whose father is colourblind and they have a daughter, what is the probability that she will be colourblind?

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Which statement about dominant and recessive alleles is not correct?

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A monohybrid cross yielded 3:1 in F2. What could be mode of inheritance?

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Ahmed’s blood CANNOT clot properly; he was diagnosed with hemophilia A. He passed this trait to his grandson through his:

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A child with AB blood group who was born to a mother of the genotype IAIA cannot have the father of the genotype:

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The total number of genes present in a particular population, at a particular time is called:

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To check the homozygosity or heterozygosity of apparently dominant trait, we do the test cross by crossing it with:

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Read the passage below to answer the question:

Hemophilia is a disorder in which blood fails to clot. Saad, a male hemophiliac, marries Sara, a normal woman and together they have four children, two boys (Ahmed and Ali) and two girls (Alia and Ayesha). None of the children display the symptoms of Hemophilia. Ahmed, Ali, Ayesha, and Ali all marry normal individuals and have children. None of Ahmeds or Ali’s children, male or female, display symptoms of hemophilia, but the sons of Alia and Ayesha display symptoms of hemophilia while the daughters of Alia and Ayesha do not.

Which of the following individuals are heterozygous for hemophilia:

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The disease, which is caused by defect in a single gene or pair of genes is referred to as:

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Which traits are most likely to affect men than women?

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Which of the following X – linked recessive trait that is more common in human males than in human females?

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What is the risk of color blind baby boy in a family when mother is color blind but father is normal?

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Genotype of blood group ‘AB’ in human is ______.

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A pure breeding plant with the dominant phenotype of character P and the recessive phenotype of character Q was crossed with another pure breeding plant with the recessive phenotype of chracter P and the dominant phenotype of Q. The offspring of this cross were crossed with a double homozygous recessive for P and Q and the following results were obtained:

22 were phenotypically dominant for P and recessive for Q
5 were phenotypically dominant for both P and Q
4 were phenotypically recessive for both P and Q
24 were phenotypically recessive for P and dominant for Q
Which one of the following types of Inheritance is illustrated by these results?

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In nature, Garden pea is

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The position of a gene on chromosome is called

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Hybrid black Guinea pigs are crossed with each other. The resulting offsprings will be:

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Baldness is most frequent in

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Haemophilia occurs because of:

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Pick the correct option about Drosophila.

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Which of the following does not belong to the same linkage group?

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The type of gene interaction in which the effect caused by a gene at one locus interfere with the effect caused by another gene at another locus is known as:

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The gene which controls ABO group has how many alleles in an individual

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Two animals are mated. One is homozygous dominant for one character and homozygous recessive for another. The other animal Is heterozygous for both characters. How many phenotypes are expected in the offspring of this cross?

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Which of the following is monohybrid cross

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Continuous variations in a population were first observed by:

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J. Seiler in 1914 discovered which type of sex determination in moths?

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An X to A ratio of ⅖ in drosophila produces:

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Phenotype for both TT and Tt is tall, so the allele T is known as:

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______ alleles both have an effect on the phenotype of a heterozygous organism:

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Read the passage below to answer the question:

Hemophilia is a disorder in which blood fails to clot. Saad, a male hemophiliac, marries Sara, a normal woman and together they have four children, two boys (Ahmed and Ali) and two girls (Alia and Ayesha). None of the children display the symptoms of Hemophilia. Ahmed, Ali, Ayesha, and Ali all marry normal individuals and have children. None of Ahmeds or Ali’s children, male or female, display symptoms of hemophilia, but the sons of Alia and Ayesha display symptoms of hemophilia while the daughters of Alia and Ayesha do not.

If one of Ali’s daughters marries a normal man,what is the probability that one of their children will display symptoms of hemophilia:

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What CANNOT be true for a man having B+ve blood group?

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A continuously varying trait is encoded by alleles of two or more different genes located at different loci, all influencing the same trait in an additive way is known as ________.

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A pea plant with yellow seed was crossed to a plant having green seeds. What will happen in F1; if plants are true breeding

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In question number 2 what will be frequency of dwarf plant in F2

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The trait “Kernel colour in corn” in controlled by how many pairs of genes

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If a heterozygous individual shows the complete effect of both alleles, the type of inheritance would be

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In ‘Complete Dominance’:

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A pure breeding tall pea plant was crossed to dwarf plant what will be the frequency of dwarf plants in F1

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Which of the following condition is hybrid A. TT B. Tt C. tt D. All of these

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An Rh negative woman is married to an Rh positive man whose father was also Rh negative. What are the chances that their child will be affected?

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