Chromosomal Basis of Inheritance — Practice Questions

Free NEET Biology multiple-choice questions on Chromosomal Basis of Inheritance. Attempt each question and reveal the answer with a full explanation.

A male human is considered for X-linked genes because he possesses only one X chromosome. Hemizygous Homozygous Heterozygous Nullizygous Synapsis occurs between : two homologous chromosomes a male and a female gamete mRNA and ribosomes spindle fibres and centromere The incorrect statement with regard to Haemophilia is (1) It is a sex-linked disease (2) It is a recessive disease (3) It is a dominant disease (4) A single protein involved in the clotting of blood is affected A human female with Tunner's syndrome :- has 45 chromosomes with XO. has one additional X chromosome. exhibits male characters. is able to produce children with normal husband. Which of the following most appropriately describes haemophilia ? Recessive gene disorder X - linked recessive gene disorder Chromosomal disorder Dominant gene disorder Select the wrong statement: Chromosomal Theory of Inheritance was proposed by Sutton Law of Dominance and Law Independent Assortment were proposed by Mendel. Linkage and recombination were discovered by Sutton Three scientists independently rediscovered the Mendel’s laws in 1900 The recessive genes located on X-chromosome in humans are always : sub-lethal expressed in females expressed in males lethal A woman has an X-linked condition on one of her X chromosomes. This chromosome can be inherited by Only grandchildren Only sons Only daughters Both sons and daughters The shorter and longer arms of a submetacentric chromosome are referred to as (1) m-arm and n-arm respectively (2) s-arm and l-arm respectively (3) p-arm and q-arm respectively (4) q-arm and p-arm respectively What map unit (Centimorgan) is adopted in the construction of genetic maps? (1) A unit of distance between genes on chromosomes, representing 50% cross over. (2) A unit of distance between two expressed genes representing 10% cross over. (3) A unit of distance between two expressed genes representing 100% cross over. (4) A unit of distance between genes on chromosomes, representing 1% cross over. What is the genetic disorder in which an individual has an overall masculine development gynaecomastia, and is sterile ? Down's syndrome Turner's syndrome Klinefelter's syndrome Edward syndrome Which Mendelian law is considered universal and has no known exceptions in sexually reproducing organisms? Law of Segregation Law of Independent Assortment Law of Dominance Law of Unit Characters Experimental verification of the chromosomal theory of inheritance was done by (1) Sutton (2) Boveri (3) Morgan (4) Mendel When the centromere is situated in the middle of two equal arms of chromosomes, the chromosome is referred as : Telocentric Sub-metacentric Acrocentric Metacentric XO type of sex determination can be found in : Birds Grasshoppers Monkeys Drosophila Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Mendel’s law of Independent assortment does not hold good for the genes that are located closely on the same chromosome. Reason (R) : Closely located genes assort independently. In the light of the above statements, choose the correct answer from the options given below: Both (A) and (R) are correct but (R) is not the correct explanation of (A) (A) is correct but (R) is not correct (A) is not correct but (R) is correct Both (A) and (R) are correct and (R) is the correct explanation of (A) Match List-I with List-II. array llll ; & List-I & ; & List-II (a) & Metacentric chromosome & (i) & Centromere situated close to the end forming one extremely short and one very long arms (b) & Acrocentric chromosome & (ii) & Centromere at the terminal end (c) & Submetacentric & (iii) & Centromere in the middle forming two equal arms of chromosomes (d) & Telocentric chromosome & (iv) & Centromere slightly away from the middle forming one shorter arm and one longer arm array Choose the correct answer from the options given below : (a)-(i), (b)-(iii), (c)-(ii), (d)-(iv) (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i) (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv) (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii) Frequency of recombination between gene pairs on same chromosome as a measure of the distance between genes to map their position on chromosome, was used for the first time by Thomas Hunt Morgan Sutton and Boveri Alfred Sturtevant Henking Broad palm with single palm crease is visible in a person suffering from- Down’s syndrome Turner’s syndrome Klinefelter’s syndrome Thalassemia Which of the following traits in garden pea was NOT studied by Mendel? Seed shape (Round/Wrinkled) Flower color (Violet/White) Stem height (Tall/Dwarf) Flower position (Axillary/Terminal) The 'Holandric' genes are genes that are located exclusively on which chromosome? Y chromosome X chromosome Chromosome 21 Mitochondrial DNA The principle that 'allele frequencies in a population are stable and is constant from generation to generation' is known as: Hardy-Weinberg Principle Darwin's Theory Lamarckism Mendelian Inheritance Centromere is required for - Movement of chromosomes towards poles Cytoplasmic cleavage Crossing over Transcription A dihybrid cross produces a phenotypic ratio of 9:3:3:1 . What is the expected ratio of a test cross involving the same characters? 1:1:1:1 3:1 9:7 1:2:1 In Antirrhinum (Snapdragon), a red flower plant was crossed with a white flower plant. The F 1 generation had pink flowers. When F 1 plants were self-pollinated, the phenotypic ratio was: 1 Red : 2 Pink : 1 White 3 Red : 1 White 9 Red : 3 Pink : 4 White All Pink What is the genotypic ratio of the F 2 generation in a Mendelian dihybrid cross? 1:2:1:2:4:2:1:2:1 9:3:3:1 1:1:1:1 3:1 In a population, if the frequency of a recessive allele 'a' is 0.4, what is the frequency of the homozygous dominant genotype 'AA' according to Hardy-Weinberg equilibrium? 0.36 0.48 0.16 0.60 Which of the following factors does NOT affect Hardy-Weinberg equilibrium? Random mating Gene flow Genetic drift Mutation Phenylketonuria is an inborn error of metabolism that is inherited as a/an: Autosomal recessive trait Autosomal dominant trait X-linked recessive trait X-linked dominant trait In the F 2 generation of a Mendelian dihybrid cross, the number of possible genotypes and phenotypes are respectively: 9 and 4 4 and 9 16 and 4 9 and 16 What is the reason for the 'Gynaecomastia' seen in individuals with Klinefelter's Syndrome? Presence of an extra X-chromosome in males Presence of an extra Y-chromosome in males Absence of one X-chromosome in females Trisomy of chromosome 21 Which of the following genetic disorders is caused by the presence of an extra X chromosome in a male ( 44 + XXY )? Klinefelter's Syndrome Turner's Syndrome Down's Syndrome Edward's Syndrome In a population in Hardy-Weinberg equilibrium, if the frequency of the dominant allele 'A' is 0.7, what is the frequency of the carriers (Aa)? 0.42 0.49 0.09 0.21 Haemophilia is more commonly seen in human males than in human females because - This disease is due to a Y-linked recessive mutation This disease is due to an X-linked recessive mutation This disease is due to an X-linked dominant mutation A greater proportion of girls die in infancy Which of the following pedigrees represents the inheritance of Myotonic Dystrophy? Autosomal Dominant Autosomal Recessive X-linked Dominant X-linked Recessive In genetic mapping, 1 map unit (centimorgan) is defined as: 1% recombination frequency 10% recombination frequency The distance between the centromere and the first gene The total length of the chromosome If a lethal recessive allele is expressed in a population, natural selection acts to eliminate it. Why does the allele often persist in the population for many generations? It is maintained in the population through heterozygous carriers Mutations constantly recreate the allele at a high rate The allele becomes dominant over time Genetic drift always favors recessive alleles If the distance between two genes is 10 centimorgans, what is the frequency of recombination between them? 10% 20% 5% 50% A person with Turner's syndrome has which of the following chromosomal compositions? 45 with XO 47 with XXY 47 with XYY 45 with YO In a dihybrid cross, if the recombination frequency between two genes is 50%, it indicates that: The genes show independent assortment The genes are tightly linked The genes are located on the same chromosome arm very close to each other The genes belong to the same linkage group and never separate If a father has an X-linked recessive disorder, he will pass the allele to: All of his daughters All of his sons Half of his sons None of his children Mendel's work remained unrecognised for several years. Who were the three scientists who independently rediscovered Mendel's results in 1900? de Vries, Correns, and von Tschermak Watson, Crick, and Wilkins Morgan, Sturtevant, and Bridges Sutton, Boveri, and Avery Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a genetic condition that predisposes to hemolysis. This condition is inherited as an: X-linked recessive trait Autosomal dominant trait Autosomal recessive trait X-linked dominant trait Cystic Fibrosis, a common genetic disorder in some populations, is caused by a mutation in the gene that codes for a protein responsible for the transport of: Chloride ions Sodium ions Oxygen Glucose A women with 47 chromosomes due to three copies of chromosome 21 is characterized by - Turner syndrome Down syndrome Superfemaleness Triploidy A woman who is a carrier for haemophilia marries a normal man. What is the probability of their sons being haemophilic? 50% 100% 25% 0% The law of 'Purity of Gametes' is another name for: Law of Segregation Law of Dominance Law of Independent Assortment Law of Co-dominance In a population of 1000 individuals, 360 belong to genotype AA, 480 to Aa and the remaining 160 to aa. Based on this data, the frequency of allele A in the population is: 0.6 0.4 0.5 0.7 If a color-blind man marries a woman whose father was color-blind, what is the probability that their first child will be a color-blind daughter? 25% 50% 75% 100% In a population of 2000 individuals, 800 individuals are homozygous dominant ( AA ), 800 are heterozygous ( Aa ), and 400 are homozygous recessive ( aa ). What is the frequency of the recessive allele ' a '? 0.4 0.2 0.6 0.5 Bateson and Punnett discovered 'Linkage' while working on Lathyrus odoratus . They used the terms 'Coupling' and 'Repulsion' to describe which arrangements? Cis and Trans arrangements Dominant and Recessive alleles Phenotype and Genotype Monohybrid and Dihybrid crosses Even if two genes are located very far apart on the same chromosome, the maximum frequency of recombination between them can never exceed: 50% 100% 25% 75% A gene showing 10 % recombination frequency between two loci implies that the distance between them is: 10 map units 1 map unit 100 map units 5 map units If two genes are very closely linked on the same chromosome, the frequency of recombination between them will be: Very low Exactly 50% Higher than 50% Always zero The law of independent assortment is NOT applicable to genes that are: Closely linked on the same chromosome Located on different chromosomes Far apart on the same chromosome Located on autosomes In which mode of inheritance do you expect more maternal influence among the offspring ? Autosomal Cytoplasmic Y-linked X-linked The salivary gland chromosomes in the dipteran larva, are useful in gene mapping because - They have endoreduplicated chromosomes These are fused These are easy to stain These are much longer in size A woman with normal vision, but whose father was colour blind, marries a colour blind man. Suppose that the fourth child of this couple was a boy. This boy - Must have normal colour vision May be colour blind or may be normal vision Will be partially colour blind since he is heterozygous for the colour blind mutant allele. Must be colour blind A man and a women, who do not show any apparent signs of a certain inherited disease, have seven children (2 daughter and 5 sons). Three of the sons suffer from the given disease but none of the daughters are affected. Which of the following mode of inheritance do you suggest for this disease Sex-limited recessive Autosomal dominant Sex-linked recessive Sex-linked dominant If a colourblind woman marries a normal visioned man, their sons will be - (1) All normal visioned (2) One-half colourblind and one-half normal (3) Three-fourths colourblind and one-fourth normal (4) All colourblind Two genes R and Y are located very close on the chromosomal linkage map of maize plant. When RRYY and rryy genotypes are hybridized, the F 2 segregation will show segregation in the expected 9 : 3 : 3 : 1 ratio segregation in 3 : 1 ratio higher number of the parental types higher number of the recombinant types. Which of the following statements is not true of two genes that show 50% recombination frequency ? The genes may be on different chromosomes The genes are tightly linked The genes show independent assortment If the genes are present on the same chromosome, they undergo more than one crossovers in every meiosis A man whose father was colour blind marries a woman who had a colour blind mother and normal father. What percentage of male children of this couple will be colour blind ? 25% 0% 50% 75% In a testcross involving F 1 dihybrid flies, more parental-type offsprings were produced than the recombinant-type offsprings. This indicates :- (1) The two genes are located on two different chromosomes. (2) Chromosomes failed to separate during meiosis. (3) The two genes are linked and present on the same chromosome. (4) Both of the characters are controlled by more than one gene. Select the correct option : Klinefelter’s syndrome is due to extra X chromosome and results in sterile male Phenylketonuria is X linked disease and results in accumulation of phenylpyruvic acid Down’s syndrome is due to triploidy and results in mental retardation Turner’s syndrome is due to trisomy and results in sterile female Select the incorrect match : Submetacentric – L-shaped chromosomes Allosomes – Sex chromosomes Lampbrush chromosomes – Diplotene bivalents Polytene chromosomes – Oocytes of amphibians Cri-du-chat syndrome in humans is caused by the- (1) Fertilization of an XX egg by a normal Y-bearing sperm (2) Loss of half of the short arm of chromosome 5 (3) Loss of half of the long arm of chromosome 5 (4) Trisomy of 21st chromosome The frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes was explained by : (1) Sutton Boveri (2) T.H. Morgan (3) Gregor J. Mendel (4) Alfred Sturtevant Select the incorrect statement. (1) Human males have one of their sex-chromosome much shorter than the other (2) Male fruit fly is heterogametic (3) In male grasshoppers 50% of sperms have no sex-chromosome (4) In domesticated fowls, sex of progeny depends on the type of sperm rather than egg If a colour blind female marries a man whose mother was also colour blind, what are the chances of her progeny having colour blindness? 50% 75% 100% 25% Which of the following statements are correct about Klinefelter’s Syndrome? A. This disorder was first described by Langdon Down (1866). B. Such an individual has overall masculine development. However, the feminine development is also expressed. C. The affected individual is short statured. D. Physical, psychomotor and mental development is retarded. E. Such individuals are sterile. Choose the correct answer from the options given below: A and B only C and D only B and E only A and E only Match List I with List II : array llll ; & List I & ; & List II A. & Down’s syndrome & I. & 11 th chromosome B. & -Thalassemia & II. & ‘X’ chromosome C. & -Thalassemia & III. & 21 st chromosome D. & Klinefelter’s syndrome & IV. & 16 th chromosome array Choose the correct answer from the options given below : A-I, B-II, C-III, D-IV A-II, B-III, C-IV, D-I A-III, B-IV, C-I, D-II A-IV, B-I, C-II, D-III With the help of given pedigree, find out the probability for the birth of a child having no disease and being a carrier (has the disease mutation in one allele of the gene) in F 3 generation. Zero 1/4 1/2 1/8 Which of the following statements are true with reference to the sex-determination in honeybees? A. An offspring formed from the union of a sperm and an egg, develops as a female (queen or worker). B. An unfertilized egg develops as a male by parthenogenesis. C. A male has half the number of chromosomes than that of a female. D. Males produce sperms by meiosis. E. Honeybees have a haplodiploid sex-determination system. Choose the correct answer from the options given below : A, B, C and E only A, B, C and D only B, C, D and E only A, B, D and E only In a population of a grasshopper species, the chromosome number of some members is 23 and some other members possess 24 chromosomes. The 23 and 24 chromosome-bearing members in this species are . females and males, respectively males and females, respectively all males all females The recombination frequency between the genes a & c is 5%, b & c is 15%, b & d is 9%, a & b is 20%, c & d is 24% and a & d is 29%. What will be the sequence of these genes on a linear chromosome? d, b, a, c a, b, c, d a, c, b, d a, d, b, c Given below are two statements : Statement I : Down's syndrome is caused by the absence of one of the X-chromosomes. Statement II : Turner's syndrome is caused by the presence of an additional copy of the chromosomes. In the light of the above statements, choose the correct answer from the options given below : Both Statement I and Statement II are correct Both Statement I and Statement II are incorrect Statement I is correct but Statement II is incorrect Statement I is incorrect but Statement II is correct Both sickle cell anemia and Huntington's chorea are- (1) Bacteria-related diseases (2) Congenital disorders (3) Pollutant-induced disorders (4) Virus-related diseases In the hexaploid wheat, the haploid (n) and basic (x) numbers of chromosomes are n = 21 and x = 21 n = 21 and x = 14 n = 21 and x = 7 n = 7 and x = 21.