Sex Determination in Humans

Q.

Opposite gender of bride

Q. Assertion : In humans, the gamete contributed by the male determines whether the child produced will be male or female.

Reason : Sex in humans is a polygenic trait depending upon a cumulative effect of some genes on X-chromosome and some on Y-chromosome.

1. If both assertion and reason are true and reason is the correct explanation of assertion
2. If both assertion and reason are true but reason is not the correct explanation of assertion
3. If assertion is true but reason is false
4. If both assertion and reason are false

Q.

There are two children in a family.

The probability that both of them are boys is

1. $\frac{1}{2}$

2. $\frac{1}{3}$

3. $\frac{1}{4}$

4. None of these

Q. A family has 5 daughters. Probability of $6^{th}$ child being boy will be

1. 1 in 2
2. 1 in 5
3. 1 in 3
4. 1 in 6

Q. Probability of four son to a couple is:

1. $\frac{1}{4}$
2. $\frac{1}{8}$
3. $\frac{1}{16}$
4. $\frac{1}{32}$

Q. If the frequency of males affected with an X-linked recessive trait in the human population is 0.20. What will be the frequency of affected females?

1. 0.04
2. 0.02
3. 0.64
4. 0.32

Q. Pollen grains of a plant $(2n=28)$ are cultured to get callus by tissue culture. What would be the number of chromosomes in the cells of callus?

1. $14$
2. $21$
3. $56$
4. $28$

Q. A colour blind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their grandson being colour blind?

1. $0.25$
2. $0.5$
3. $1$
4. Nil

Q.

If birth to male child and birth to female child are equal probable, then what is the probability that atleast one of the three children born to a couple is male?

1. $\raisebox{1ex}{$4$}\!\left/ \!\raisebox{-1ex}{$5$}\right.$

2. $\raisebox{1ex}{$7$}\!\left/ \!\raisebox{-1ex}{$8$}\right.$

3. $8/7$

4. $1/7$

Q. In our society the women are often blamed for giving birth to daughters. Can you explain why this is not correct?

Q. Define diploid
define tetraploid

Q. Amniocentesis is a

1. sex determination test of a foetus based on the pattern in chromosomes of foetal cells derived from the amniotic fluid surrounding the developing embryo.
2. sex determination test of a foetus based on the pattern in chromosomes of maternal cells derived from the amniotic fluid present in the placenta.
3. sex determination test of a newborn baby based on the pattern in chromosomes derived from amniotic fluid present in the placenta.
4. sex determination test of a newborn baby based on the pattern in chromosomes derived from amniotic fluid present in the blood.

Q. Mohan has two daughters. He blames his wife for bearing only daughters and no son. How will you convince Mohan that his wife has no role in giving birth to daughters only so that she should not be blamed for it. Further, females are rather more important component of society, What values are involved in this advice?

Q. ntMr. Stevan is suffering from haemophillia and cystic fibrosis. His father is heterozygous for cystic fibrosis. The probability of Stevans sperm having recessive X- linked as well as autosomal allele is ?n nt(1) 1/4n nt(2) 1/16n nt(3) 1/2n nt(4) 1/8n

Q.

A man can inherit his X - chromosome from his

a.) Maternal grandfather or maternal grandmother

b.) Father

c.) Maternal grandfather

d.) Paternal grandfather

e.) Paternal grandmother

Q.

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

1. Only grandchildren
2. Both sons and daughters
3. Only daughter
4. Only sons

Q. Explain sex determination in humans with line diagram.

Q. Explain sex determination in human beings.

Q. XY sex chromosomes were discovered by

1. Gregor Johann Mendel
2. Nettie Stevens
3. M.J.D. White
4. Robert Brown

Q. Explain how equal genetic contribution of male and female parents is ensured in the progeny.

Q. Explain how sex is determined in human babies.

Q. Five Mark Questions :
(a) Explain the mechanism of sex determination in humans.
(b) Differentiate between male heterogamety and female heterogamety with the help of an example of each

Q. A family has five girls and no son. Probability of son as the 6th child will be:

1. 50%
2. 75%
3. Full
4. No chance

Q. Write short note on sex determination in humans.

Q. Assertion :XX-XY type of sex determination mechanism is an example of female heterogamety and is found in Drosophila. Reason: Male heterogamety is seen in moths where males produce two different types of gamete.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. In human sperm, besides autosomes the chromosome complement contains

1. X and Y
2. Either X or Y
3. Y only
4. X only

Q. Explain sex determination in humans with the help of flow-chart.

Q. Assertion :In humans the gamete contributed by the male determines whether the child produced will be male or female. Reason: Sex in humans is polygenic trait dependent upon the cumulative effect of some genes on X-chromosome and some on Y-chromosome.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
3. Assertion is correct but Reason is incorrect.
4. Both Assertion and Reason are incorrect.

Q. Mrs. Verma has an autosomal gene pair 'Bb' and she contain x-linked gene 'd'. What is the percentage of gamete, which contain 'bd' genes?

1. 1/4 or 25%
2. 1/2 or 50%
3. 3/4 or 75%
4. 1 or 100%

Q.

Assume that in a family, each child is equally likely to be a boy or a girl. A family with three children is chosen at random. The probability that the eldest child is a girl given that the family has at least one girl is