How is the Sex of the Child Determined in Human Beings? - Science


 How is the sex of the child determined in human beings?



In human beings, the females have two X chromosomes and the males have one X and one Y chromosome. Therefore, the females are XX and the males are XY.
The gametes, as we know, receive half of the chromosomes. The male gametes have 22 autosomes and either X or Y sex chromosome.
Type of male gametes: 22+X OR 22+ Y.
However, since the females have XX sex chromosomes, their gametes can only have X sex chromosome.

Type of female gamete: 22+X

Thus, the mother provides only X chromosomes. The sex of the baby is determined by the type of male gamete (X or Y) that fuses with the X chromosome of the female.

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Chapter 9: Heredity and Evolution - Intext Questions [Page 147]


NCERT Science Class 10
Chapter 9 Heredity and Evolution
Intext Questions | Q 4 | Page 147


Explain sex determination in human beings.

Answer the following questions related to sex determination in human beings:
i. What is sex chromosome?
ii. How many pairs of chromosomes are present in human beings?
iii. How is the sex of the human offspring determined?
iv. Draw a diagram depicting sex determination in man.

If X chromosome is inherited from mother and Y from father, the offspring will be male.

Differentiate between male and female heterogamety

Explain the mechanism of sex determination in birds.

Differentiate between 'ZZ' and 'XY' type of sex-determination mechanisms.

"The sex of a newborn child is a matter of chance and none of the parents may be considered responsible for it". Draw a flow chart showing determination of sex of a newborn to justify this statement.

Write notes on Sex determination in the unborn baby.

Which of the following is an example of ZW – ZZ type of mechanism of sex determination?

There are ................ pairs of chromosomes in the human being.

There are two sets of chromosomes in the zygote.

Explain the mechanism of 'sex determination' in birds. How does it differ from that of human beings?

What are the chromosomes XY and XX known as?

If a normal human cell has 46 chromosomes, how many chromosomes will be there in a human (i) sperm cell, and (ii) zygote?

In a human, how many chromosmes are present in a skin cell?

The two versions of a trait (character) which are brought in by the male and female gametes are situated on :
(a) copies of the same chromosome
(b) sex chromosomes
(c) two different chromosomes
(d) any chromosomes

The person A has only B chromosomes in all its gametes. On the other hand, another person C has chromosome D in half of gametes and chromosome E in the other half of gametes. When chromosomes B and D combine during fertilisation, a female zygote results. On the other hand, combination of B and E chromosomes produces a male zygote.
(a) What are chromosomes (i) B (ii) D, and (iii) E?
(b) Out of B, D and E, which two chromosomes are of the same type?
(c) Which chromosome is smaller in size?
(d) What is the general name of chromosomes such as B and E?
(e) Out of the two persons A and C, which one is (i) male, and (ii) female?

Name two animals which have nineteen pairs of chromosomes. 

Among lion, tiger and domestic cat, al the three have the same number of 38 chromosomes, yet they have different appearances. How do you account for such differences?

Does the sex of the child depend on the father or it is just a matter of chance? Discuss 

Why did T. H. Morgan select Drosophila melanogaster to study sex linked genes for his lab experiments ?

________ shows haplo-diploid type of sex-determination.

Choose the correct answer from the four options given below : 
In a human male, a sperm will contain : 

What is heterogamety ? Explain the mechanism of sex determinatin in Drosophila.

Define the following:

Define the following:
Sex chromosomes

Define the following:
Sex-linked characters

What do you understand by sex-linked inheritance?

Choose the correct answer :
Human sex chromosomes are __________

With the help of a chart, explain the method of sex determination in honeybees.

In which livings, female decides the sex? Give two examples.

(a) How many pairs of autosomes and Paris of sex chromosomes are present in a human being?  
(b) Which chromosomes are present in Females? 
(c) Which chromosomes are present in Male? 
(d) How does sex determination take place in human beings? 

Answer the following question:
How is sex determined in human beings? Explain with the help of a diagram. 

Write the functional activity of the following structure:


Short Answer Question.

“Father is responsible for determination of sex of child and not the mother”. Justify.

How drones are produced in honey bees?

Explain the mechanism of sex determination in humans with a suitable chart.

Kavitha gave birth to a female baby. Her family members say that she can give birth to only female babies because of her family history. Is the statement given by her family members true? Justify your answer.

XO type of sex determination and XY type of sex determination are examples of ____________.

ZW-ZZ system of sex determination occurs in

Which of the following is incorrect regarding ZW-ZZ type of sex determination?

What is haplodiploidy?

Distinguish between heterogametic and homogametic sex determination systems.

What is Lyonisation?

Differentiate Intersexes from Supersexes.

What is male heterogamety?

Brief about female heterogamety.

Explain the mode of sex determination in honeybees.

How is sex determined in human beings?

How many ovum are formed when a diploid cell undergoes meiosis, during oogenesis?

Identify the female heterogamety from the chromosomal complements given below.

From the following which option correctly represents the normal genetic constitution of a ovum?

There are five daughters and no son in a family. It is because

Which type of sex determination is observed in honey bee?

Match the items of Column I with Column II:

  Column I   Column II
i. XX-XO method of Sex Determination a.  Turner  syndrome
ii. XX-XY method of Sex Determination b. Female heterog ametic
iii. karyotype-45 c. Grasshopper
iv. ZW-ZZ method of Sex Determination d. Female homogametic

Diploid larvae which get royal jelly as food develops into ____________ and other develops into workers (sterile females).

Identify the organism in which ZZ-ZW type of sex determination is observed.

Which of the following organisms has haploid number of chromosomes?

Which of the following develops through parthenogene is?

The ‘X’ body of Henking was observed in ______.

ZZ / ZW type of sex determination is seen in ______.

Number of autosomes present in liver cells of a human female is ______.

Grasshopper is an example of XO type of sex determination in which the males have ______.

Human offspring’s sex is determined ______ 

The maleness of a child is determined by ______ 

A woman has only daughters. Analyse the situation genetically and provide a suitable explanation.

The belief that the mother is completely responsible for the sex of the child is wrong because the child

Structures present in a cell which is responsible for determination of the sex of a baby is

Fill the blank circles in figure and identify the sex of child A and B. 

Sex in honey bee is determined by ______.

The chromosomal constitution of a human female can be written as ______

Female heterogamy is shown by

Which of the following group shows ZW-ZZ type of sex determination?

What is the probability of a girl or a boy being born into a family? Justify your answer.

The sex chromosome in a human ovum is ______.


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