Plus Two Zoology Chapter Wise Previous Questions Chapter 3 Principles of Inheritance and Variation are part of Plus Two Zoology Chapter Wise Previous Year Questions and Answers. Here we have given Plus Two Zoology Chapter Wise Previous Questions Chapter 3 Principles of Inheritance and Variation.
Kerala Plus Two Zoology Chapter Wise Previous Questions and Answers Chapter 3 Principles of Inheritance and Variation
In classroom discussion, a student said that the sex of the baby is determined by father. Analyse the statement and give reason for it. [March-2018]
In humans sex determination mechanism is XY type A pair of x chromosomes are present in the female, where as the presence of an x and y chromosome are determinants of the male characteristic. During spermatogenesis the male produce two types gamates X and Y besides autosomes and the female produce only one type of ovum with an X chromosome. There is an equal probability of fertilization of the ovum with the sperm carrying with X or Y chromosome.
a. Observe the above cross and name the phenomenon.
b. Write down the theoretically given explanations of the phenomenon.
a. Incomplete dominance
b. “It is a phenomenon in which phenotype of the F( hybrid offspring does not resemble any of the parent even it is the intermediate between the expression of two alleles in their homozygous state”.
Heamophilia,Sickle cell anemia and Phenyl Ketonurea are Mendelian disorders. [March-2018]
a. What do you mean by Mendelian disorder?
b. Which one of the above is an example of inborn error of metabolism? Mention the cause of the disorder.
a. Mendelian disorders are genetic disorders caused due to alteration or mutation in a single gene.
b. Phenyl Ketonurea
It is an inborn error of metabolism in which an affected individual lacks an enzyme that converts the amino acid phenylalanine into tyrosine.
The following table shows the F2 generation of a dihybrid cross. Identify the ‘Phenotype’ with homozygous recessive genotype. Find out A:B:C:D. [Model-2017]
B is the homozygous recessive geno type.
A:B:C:D = 3:1:9:3
Which of the following do not have similar sex chromosomes? (Homo-gametic)
a. Human female
b. Drosophila female
c. Bird female
d. Bird male [Model-2017]
c. Bird female.
Examine the following fragment of beta globinchain in human haemoglobin and identify the hereditary disease with reason.
- Substitution of glutamic acid by valine at the sixth position of the beta globin chain of haemoglobin molecule (Point mutation).
- i. The RBC become sickle shaped causing a disease sickle cell anaemia.
ii.It affect the 02 carrying capacity of RBC.
Observe the figures and answer the questions.
a. Identify the syndromes A and B.
b. What is the chromosome numbers in A and B? [March-2016]
A – Klinefelter’s syndrome
B – Turners syndrome
b. Chromosome number in A = 47 Chromosome number in B = 45
Study the following cross and answer the questions.
[Hint : ABO blood group in man is controlled by three alleles IA, IB and i]
a. Write the genotypes of Father, Mother and son.
b. The type of dominance of human blood group inheritance is [March-2016]
a. genotype of father IA i
genotype of mother IB i
genotype of son ii
Which of the following is not a Men-delian disorder ?
Colour blindness, Down’s syndrone, Haemophilia, Thalassemia [March-2016]
Fill in the blanks:
a………….. is a metabolic disorder that occurs due to the lack of an enzyme, that converts phenylalanine to tyrosine.
b………….. is a disease caused by the substitution of Glutamic acid by valine at 6th position. [March-2015]
b. Sickle-cell anaemia
Identify the syndrome from the diagram, and write the genotype.
a. It occurs in both sexes (male and female)? Write the reason. [March-2015]
a. Down’s syndrome, 45A+XY or 45A + XX
b. AB, Ab, aB, ab
“Gopalan argues that if father is of ‘A’ blood group, mother is of ‘B’ blood group. Their children can only be ‘A’ group, B group or ‘AB’ group.”
a. Do you agree with Gopalan’s Argument?
b. Give reason. [March-2014]
b. A blood group means it exist as iA or iA iA, B blood group means, it exist as iBi, iBiB. So the child can have genotype.
So the child can have ‘O’ blood group also. Blood group system in human is an example for co-dominance.
Difference in chromosome number of some human beings A, B, C and D are given below:
i. 22 pairs of Autosomes
ii. 22 pairs of Autosomes + XO
iii. 22 pairs of Autosomes + 1 Auto- some
iv. 22 pairs of Autosomes + XXY
a. Identify the person who suffers from Klinefelter’s syndrome. Write its symptoms.
b. Differemntiate between aneuploidy and polyploidy. [March-2014]
a. iv. suffer from Klinefelter’s syndrome.
Symptoms: Person (male) shows feminant characters, sterile male.
b. Polyploidy is presence of extraset of chromosome. So that cromosome number increases. Aneuploidy is the loss or gain of chromosome during mieosis.
eg., Monosomy (2n-1), trisomy (2n+1).
Explain the phenomenon shown in the following figure and the reason for difference in the production of recombinants in Cross A and Cross B as explained by Morgan. [March-2014]
T.H. Morgan explained linkage. In cross, the strength of linkage between y and w gene is very strong than linkage between w and m genes. When strength of linkage increases, decrease the recombinant. So that recombination decreases in the case form cross A.
Note the relationship between the first two words and suggests a suitable word to the fourth place.
a. Down Syndrome : 47 :: Turner’s syndrome:………….
b. Trisomy : 2n + 1 :: Monosomy : ……….[Model-2014]
a. 45 b. 2n-1
The first child of a couple is affected with Phenylketonuria. During the second pregnancy they visited a ge netic counsellor and he prepared a pedigree chart of their family.
It is the study of inheritance of genetic traits in several generations of human family in the form of a family tree diagram.
Identify the traits from the pedigree chart. Give one example each. [March-2013]
a. Autosomal dominant trait,
eg., muscular dystrophy
b. Autosomal recessive trait,
eg., sickle-cell anaemia.
A poultry farm manager was cursing his hens for producing lion share of cocks in its progeny. Hearing this, Kumar, farm attender starts to blame his wife for delivering, consecutive girl children. Analyze the situations scientifically and state whether you agree with Kumar. [March-2013]
I cannot agree with Kumar because the sex of progeny is not determined by parents but by chance by which the combining of gametes produced by parents. In birds sex determination mechanism is as follows.
When experiments on snapdragon was conducted, Raju got the flower colour ratio 1 red: 2 pink: 1 white, does it follow Mendelian inheritance ratio? Justify your answer. [March-2013]
No, Here Ft shows intermediate condition i.e., pink while Red and white flowered plants crossed. This phenomenon is called incomplete dominance.
Val-His-Leu-Thr-Pro-Glu Val-Hist-Leu-Thr-Pro-Val Amino acid sequence of 3-chain of haemoglobin of two individuals are shown above.
a. Which one is the haemoglobin of sickle-cell anaemia patient and why?
b. Write any two symptoms of this disease.
a. The chain with valine amino acid on sixth position instead of glutamic acid is the haemoglobin of sickle-cell patient
(i.e., IIn chain).
b. RBC become sickle shaped. It results in earlier distinction of RBC resulting in Anaemia.
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