CBSE Questions for Class 12 Medical Biology Principles Of Inheritance And Variation Quiz 11 - MCQExams.com

In human beings, sex determination has recently been studied in great details using technique of molecular biology. The most important gene located on Y chromosome and involved in sex determinations is?
  • SRY gene
  • Sx $$1$$ gene
  • ZFY gene
  • tra gene
Two good examples of obligate plantanimal Mutualism would include ___________________.
  • Mycorrhiza and fairy rings
  • Lichens and corraloid roots of Cycas
  • Azolla-anabaena symbiosis and sunflower-butterflies
  • Acacia-ants and Yucca-yucca moth
In specific population of a species, individuals showing $$2n+1$$ or $$2n-1$$ set of chromosomes are called respectively.
  • Nullisomics and monosomics
  • Monosomics and trisomics
  • Trisomics and monosomics
  • Nullisomics and trisomics
When the dominant alleles(or wild type) say AB are present on one chromosome and its alternative recessive allele(ab) are located on the other homologous chromosome AB/ab, then the linkage is said to be in.
  • Repulsion phase
  • Coupling phase
  • Neutral phase
  • Dominant phase
Baldness is more common in men than in women. It could be explained on the basis that 
  • Genes of baldness are located on X-chromosomes only
  • Baldness genes are located on Y-chromosomes
  • Genes of baldness are autosomal but influenced by androgenns
  • None of the above
A homozygous recessive with cd genes was crossed with dominant (+ +).If their hybrid is test crossed and the following result was obtained 
++ - 900
cd - 880
+d - 115
+c - 105
than what will be the distance between genes c and d.
  • 5.75 unit
  • 11 unit
  • 44 unit
  • 90 unit
Which of the following is a case of auto allopolyploidy?
  • AA,AA,A
  • AA, AA, AB
  • AA-1
  • 2n-2
Give a chromosome segment a-b-c with $$40\%$$ interference, the frequency of double cross-over (dco) will be.
  • $$20\%$$
  • $$10\%$$
  • $$1.2\%$$
  • $$0.12\%$$
Sickle cell anaemia is a case of
  • Transition
  • Transversion
  • Frame shift mutation
  • Silent mutation
What will happen, if the sperm containing $$'X'$$ chromosomes fertilises the Ovum?
  • Female child born
  • Male child born
  • No Zygote formation
  • Down Syndrome
Sudden change in genetic character is known as 
  • Mutation
  • Mitotic division
  • Meiotic division
  • Recombination
Presence of which of the following in the cells of amniotic fluid is responsible for the sex determination of the embryo?
  • Barr Body
  • Sex Chromosomes
  • Chiasmata
  • Antigen
What is the number of chromosomes in an individual with Turner's syndrome?
  • $$44$$
  • $$45$$
  • $$46$$
  • $$47$$
How many number of barr body will be present in female suffering from Turner's syndrome?
  • Zero
  • One
  • Two
  • Three
Wife is PTC non-taster and husband is PTC taster. Their son is taster but daughters are non-tasters. This is not a sex linked trait. Which pedigree is correct?
A gamete affected by non-disjunction would have
  • The potential for a genetic disorder
  • One extra or one missing chromosome
  • Change from the normal chromosome number
  • All of the above
$$F_1$$ offspring of the monohybrid cross AA $$\times$$ aa are _______.
  • All AA
  • All Aa
  • All aa
  • 1/2 AA and 1/2 aa

The condition in which there are more than two complete sets of chromosome is called
  • Aneuploidy
  • Polyploidy
  • Deletion
  • Duplication

In all the Mendels experiments, the two alleles causing a trait were
  • dominant-recessive
  • codominant
  • incompletely dominant
  • corecessive

Study the pedigree given above and select the type of inheritance of the trait?
863866_85a4a0feec574210bfcccc3ce00b5524.png
  • X-linked recessive
  • Y-linked
  • Autosomal recessive
  • Autosomal dominant
All of the following are sexual sources of genetic variation except
  • Crossing-over
  • Mutation
  • Production of offspring from two parents
  • Random fertilization
Non-disjunction can be caused by
  • Multiple independent assortments
  • Failure of chromosomes to separate during meiosis
  • Segregation in meiosis
  • Crossing over in mitosis
The $$F_2$$ generation is conventionally produced by random union of the F$$_1$$ gametes.
  • True
  • False
No genes are common to both the X and Y-chromosomes.
  • True
  • False
Genetic variability can be created by
  • mass selection
  • mutation
  • clone selection
  • hybridization
In the following human pedigree, the filled symbols represent the affected individuals. Identify the type of given pedigree
875734_a7479d7749a64b4fbc7b6a0439f97d34.jpg
  • X - linked dominant
  • Autosomal dominant
  • X- linked recessive
  • Autosomal recessive
Chromosome duplication without nuclear division refers to 
  • Meiosis
  • Mitosis
  • Androgenesis
  • Endomitosis
Choose the correct answer from the alternatives given.

In fruit flies, the long wing is dominant to the vestigial wing. When heterozygous long-winged flies were crossed with vestigial-winged flies, 192 offsprings were produced. Of these, 101 had long wings and 91 had vestigial wings. If an exact Mendelian ratio had been obtained, then the number of each phenotype would have been Long-winged: vestigial-winged.
  • Long winged 64, Vestigial winged - 128
  • Long winged - 96, Vestigial winged 96.
  • Long winged - 128, Vestigial winged 64
  • Long winged - 192, Vestigial winged 0
Choose the correct answer from the alternatives given.

A tobacco plant heterozygous for a recessive character is self-pollinated and 1200 seeds are subsequently germinated. How many seedlings would have the parental genotype?
  • 1250
  • 600
  • 300
  • 2250
Study the given pedigree chart of a certain family and select the correct conclusion which can be drawn for the character.
929666_045c6d7b8bbb4993bc94e690616e6005.jpg
  • The female parent is heterozygous.
  • The parents could not have had a normal daughter for this character.
  • The trait under study could not be colourblindness.
  • The male parent is homozygous dominant.
The mutations that involve addition, deletion or substitution of a single base pair in a gene are referred to as
  • point mutations
  • lethal mutations
  • silent mutations
  • retrogressive mutations.
Choose the correct answer from the alternatives given.

What is the probability of production of dwarf offsprings in a cross between two heterozygous tall pea plants?
  • Zero
  • 50%
  • 25%
  • 100%
In an organism, tall phenotype is dominant over recessive dwarf phenotype, and the alleles are designated as $$T$$ and $$t$$, respectively. Upon crossing two different individuals, total 250 offsprings were obtained, out of which 124 displayed tall phenotype and rest were dwarf. Thus,, the genotype of the parents were
  • $$TT \times TT$$
  • $$TT \times tt$$
  • $$Tt \times Tt$$
  • $$Tt \times tt$$
A plant species A has a diploid chromosome number ofAnother plant species B has a diploid chromosome number ofThe allopolyploid developed by hybridization of A and B shall have a diploid chromosome number as
  • 14
  • 28
  • 40
  • 56

A woman has an X linked condition on one of her X chromosomes. This chromosome can be inherited by

  • Only grandchildren
  • Only daughter
  • Both sons and daughters
  • Only sons
Choose the correct answer from the alternatives given.

In XO type of sex determination
  • Females produce two different types of gametes
  • Males produce two different types of gametes
  • Females produce gametes with Y chromosome
  • Males produce gametes with Y chromosome.
Select the incorrect statement regarding the pedigree analysis.
  • Solid symbols show only unaffected individuals.
  • Proband is the person from which case history starts.
  • It is useful for genetic counsellors.
  • It is an analysis of traits in several generations of a family.
Experimental verification of chromosomal theory of inheritance was done by
  • Sutton and Boveri
  • Morgan et al
  • Henking
  • Karl Correns
ABO blood grouping in human beings cites the example of
  • Incomplete dominance
  • Co-dominance
  • Multiple allelism
  • Both B and C
Grasshoppers an example of XO type of sex determination in which the males have?
  • One X chromosome
  • One Y chromosome
  • Two X chromosomes
  • No X chromosome
Which one is the incorrect match?
Rate of mutation is affected by _______________.
  • Temperature
  • X-rays
  • Gamma rays
  • All of these
Choose the correct answer from the alternatives given.

In four o clock plants, the gene for red flower colour (R) is incompletely dominant over the gene for white flower colour (r), hence the plants heterozygous for flower colour (Rr) have pink flowers. What will be the ratio of offsprings in a cross between red flowers and pink flowers?
  • 75% Red flowers, 25% Pink flowers
  • All Red flowers
  • 50% Red flowers, 50% Pink flowers
  • Red:Pink:White:: 1:2:1
Study the given pedigree chart showing the inheritance of an X-linked trait controlled by gene r.
What will be the genotypes of individuals A, B, C, and D respectively?

932035_56707e75c183484785c2094b0fa409e5.png
  • $$XX$$, $$X^rY$$, $$X^rX$$, $$XY$$
  • $$X^rX^r$$, $$XY$$, $$XX$$, $$XY$$
  • $$X^rX$$, $$X^rY^r$$, $$X^rX^r$$, $$X^rY$$
  • $$XX$$, $$X^rY^r$$, $$XX$$, $$XY$$
Choose the correct answer from the alternatives given.

How many types of gametes can be produced by a diploid organism who is heterozygous for 4 loci?
  • 4
  • 8
  • 16
  • 32
An organism possessing a chromosomal complement different from the diploid one such as 2n - 1 or 2n+ 1 is called
  • Allopolyploid
  • Aneuploids
  • Ampindiploid
  • Autopolyploid
Fused ear lobes appear En the progeny due to an autosomal recessive gene. Work out the genotypes of members in the given pedigree.
932054_b397c2070ff24663bfb8467f598f2c3e.png
  • I-2-aa, II-3-Aa, III-1-Aa
  • I-2-aa, II-3-AA, III-1-AA
  • I-2-Aa, II-3-Aa, III-1-Aa
  • I-2-aa, II-3-Aa, III-1-AA
$$\alpha$$-1 Antitrypsin is _________________.
  • An antacid
  • An enzyme
  • Used to treat arthritis
  • Used to treat emphysema
Choose the correct answer from the alternatives given.
Study the pedigree chart of a family showing the inheritance of sickle-cell anemia.
The trait traced in the above pedigree chart is

932073_31405c4212c5427fae7a354e93660d61.png
  • Dominant X-linked
  • Recessive X-linked
  • Autosomal dominant
  • Autosomal recessive.
Study the given pedigree chart for sickle-cell anaemia and select the most appropriate option for the genotypes. 
932676_d111c7d923e74bfcbdf2677484740f85.png
  • Genotypes of parents - $$Hb^A \, Hb^5 \, Hb^A \, Hb^A$$

    Genotypes of 1st & 3rd child in $$F_1 \, - \, Hb^A \, Hb^A \, Hb^A \, Hb^S$$
  • Genotypes of parents - $$Hb^A \, Hb^5 \, Hb^A \, Hb^S$$

    Genotypes of 1st & 3rd child in $$F_1 \, - \, Hb^A \, Hb^A \, Hb^A \, Hb^A$$
  • Genotypes of parents - $$Hb^A \, HbA \, HbA \, Hb^S$$

    Genotypes of 1st & 3rd child in $$F_1 \, - \, Hb^A \, Hb^A \, Hb^S \, Hb^S$$
  • Genotypes of parents - $$Hb^A \, Hb^S \, Hb^A \, Hb^S$$

    Genotypes of 1st & 3rd child in $$F_1 \, - \, Hb^A \, Hb^S \, Hb^S \, Hb^S$$
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