HARD
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What is haemophilia? Explain its inheritance with the help of suitable charts. 

Important Questions on Principles of Inheritance and Variation

MEDIUM
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders

A woman heterozygous for colour blindness marries a colour-blind man. What would be the ratios of carrier daughters, colour-blind daughters, normal sons, and colour-blind sons in the F1 generation?

HARD
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
A colourblind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their sons being colourblind?
HARD
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
Match the human disorders shown in Group I with the biochemical processes in Group II. Choose the correct combination.
 
Group I Group II
P. Phenylketonuria i. Melanin synthesis
Q. Albinism ii. Conversion of Phenylalanine to Tyrosine
R. Homocystinuria iii. Tyrosine degradation
S. Argininemia iv. Methionine metabolism
  v. Urea Synthesis
MEDIUM
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
Both male and female have normal vision though their fathers were colour-blind, and mothers did not have any gene for colour blindness. The probability of their daughter becoming colour-blind is
HARD
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
Satish is a colour blind boy. His mother has normal vision but his maternal grandfather is colour blind. His father and maternal grandmother have normal vision. Explain the pattern of inheritance with a suitable chart.
EASY
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
Which of the following muscular disorders is inherited?
MEDIUM
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
If a colour-blind man marries a woman who is homozygous for normal colour vision, the probability of their son being colour-blind is
HARD
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
If the mother is a carrier of colour blindness and the father is normal, show the possible genotype and phenotype of the offspring of the next generation with the help of a punnet square.
MEDIUM
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
A carrier haemophilic female marries a normal male. What will be the phenotype of progeny? Explain with suitable chart.
MEDIUM
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
A woman has X-linked condition on one of her X chromosomes. These chromosomes can be inherited by:
EASY
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
State two reasons why the blood of haemophilia persons clot very slowly or not at all.
MEDIUM
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders

Statement I : All the three types of allosomal genes - X linked, Y linked and XY linked are present only in male human being.
Statement II : Only X linked and not XY linked genes are present in female human being.

The correct option among the following is

EASY
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
A woman (whose father is haemophilic and mother is homozygous normal) married a normal man and had two sons and two daughters. What are the chances of their sons being haemophilic?
EASY
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
A couple has two sons and two daughters. Only one son is colour blind and the rest of the siblings are normal. Assuming colour blindness is sex-linked, which ONE of the following would be the phenotype of the parents?
HARD
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
Generally, it is observed that human males suffer from haemophilia more than human females, who rarely suffer from it. Explain giving reasons. 
HARD
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
When a normal female is married to a colour-blind male, then work out the colour blindness in the progeny of these parents with the help of a diagram.
MEDIUM
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
Why is haemophilia uncommon in females?
HARD
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
Pick out the correct statements:
(i) Haemophilia is a sex-linked recessive disease.
(ii) Down's syndrome is due to aneuploidy.
(iii) Phenylketonuria is an autosomal recessive gene disorder.
(iv) Sickle cell anaemia is an X-linked recessive gene disorder.
EASY
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
Which ONE of the following Mendelian diseases is an example of X-linked recessive disorder?
MEDIUM
Biology>Genetics and Evolution>Principles of Inheritance and Variation>Genetic Disorders
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?