Gametogenesis class 12 ncert: Oogenesis spermatogenesis in human reproduction,CBSE

Gametogenesis class 12 ncert: Oogenesis spermatogenesis in human reproduction,CBSE

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Hello students,In this section,we are going to look NCERT important topic Gametogenesis class 12 ncert of Human Reproduction chapter . First It has been taken a NCERT paragraph or sentences then It has been explained in simple english words and Hindi too.Explain box has unofficial words(less than20%) so We recommended you that trying using ncert line for your written exam.

Gametogenesis class 12 ncert main content you can direct reach your wanted topic by click in the box

what is gametogenesis?Male (Gametogenesis)
Female(Gametogenesis)Sperm parts
Spermiation Oogenesis
Ovulation Primary oocyte
Gametogenesis class 12 ncert MCQGametogenesis class 12 ncert MCQ answer

What is gametogenesis?

Definition:  Gametogenesis is process by which male produce sperms and feminine produce ovum, male produce sperm by the method of spermatogenesis while feminine produced ovum by the method of oogenesis.

GAMETOGENESIS: The primary(first) sex organs the testis within the male and the ovaries within the female produce gametes, i.e, sperms and ovum, respectively, by vital important  process called gametogenesis.

Eexplain of above paragraph

In English

  • Primary sex organs: Testis of male and ovaries of female are primary sex organs.
  • Sperms produced from the testis and ovum produced from ovaries.

In Hindi

  • Primary sex organs:Male ka testis aur female ke ovary ko primary sex organs khate hai.
  • Sperms ka utpad testis se hota hai aur ovum Ka utpad ovaries se hota hai.

Gametogenesis class 12 ncert has two parts male gametogenesis and female gametogenesis

Male(Gametogenesis )

In testis, the immature male germ cells (spermatogonia) produce sperms through the process of spermatogenesis that begins at puberty.
The spermatogonia (singular. spermatogonium) present on the inside wall of seminiferous tubules multiply through mitotic division or reduction division and increase in numbers.

Explain above paragraph

In English

  • Immature male germ cell called Spermatogonia
  • Spermatogonia produced sperms by the processes of spermatogenesis
  • Spermatogenesis begins at puberty(about 10-14 ages old)
  • spermatogonia present seminiferous tubules’s walls
  • By mitotic division seminiferous tubules increase in numbers

In Hindi

  • Immature( apripakat) male germ cells Jise Spermatogonia Kahate Hain
  • spermatogenesis prakriya se spermatogonia sperm produce karta hai
  • Spermatogenesis Bal avastha se shuru Hota Hai(10-14 ages old)
  • Spermatogonia Seminiferous tubules wall mai present rahta hai
  • mitotic division se seminiferous tubules apne Number Ko banata hai

Each spermatogonium is diploid and contains 46 chromosomes. Some of the spermatogonia called primary spermatocytes periodically undergo meiosis. 

Explain above paragraph

In English

  • Spermatogonia are diploid
  • It has 46chromosomes
  • Some spermatogonia is called primary spermatocytes and undergoes meiosis division

In Hindi

  • Spermatogonia haploid hote hai
  • Esme 46 Chromosomes hote hai
  • Kuch spermatogonia ko primary spermatocytes kahte hai aur eska meiosis division hota hai

 A primary spermatocyte completes the first meiotic division (reduction division) leading to formation of two equal, haploid cells called secondary spermatocytes, which have only 23 chromosomes each, 

Explain above paragraph

In English

  • A primary spermatocyte complete the first mitotic division
  • Secondary Spermatocytes have haploid,equal(both cells),23chromosomes each

In Hindi

  • Primary spermatocytes first mitotic division complete karta hai
  • Secondary spermatocyte ke haploid cell Hote Hain aur 23 chromosomes partek cells Mein Hota Hai

The secondary spermatocytes undergo the second meiotic division to produce four equal, haploid spérmatids
The spermatids are transformed into spermatozoa (sperms) by the process called spermiogenesis

Explain above paragraph

In English

The secondary spermatocytes undergo the second meitotic division

The secondary spermatocytes have four equal haploid spermatids

Then the spermatids are transformed into sperms(spermatozoa)

Spermiogenesis is a process by witch sperms are formed.

In Hindi

Secondary spermatocyte secondary mitotic division Mein enter Hota Hai

Secondary spermatocyte ke 4 barabar equal haploid spermatids cells hota hai

Uske bad spermatids sperms(spermatozoa)mein transfer Hota Hai

Spermiogenesis ak parkirya hai jisse sperms formation hota hai.

Note: Gametogenesis class 12 ncert (human reproduction) not only very important and interesting topic also more and more frequently ask question from this chapter.


After spermiogenesis, sperm heads become embedded in the Sertoli cells, and are finally released from the sèminiférous tubules by the process called spermiation.  

Explain above paragraph

In English

just after spermiogenesis sperm’s head embedded in the sertoli cells

Then sperms are released from the seminiferous tubules

Spermiation is a process by which sperms released from seminiferous tubules

In Hindi

Spermatogenesis ke bad sperms ka head sertoli cells mein ghar Jaate Hain

Tab sperms seminiferous tubules Se Bahar Aata Hai

Spermiation oh process Hai Jisse sperms ka seminiferous tubules se bahar nikal aata hai

Spermatogenesis starts at the age of puberty due to significant increased in the  secretion of gonadotropin releasing hormone(GnRH). This, if you recall  is a hypothalamic hormones hormone 

  The increased levels of GnRH then acts at the anterior  pituitary glands and stimulates secretion of two gonadotropins— luteinising hormone (LH) and folliclel stimulating hormone (FSH). LH acts at the Leydig cells and stimulates synthesis and secretion of androgens. 

Explain above paragraph

In English

At the age of puberty the secretion of gonadotropin releasing hormone (GnRH) significant increased as a result Spermatogenesis starts at puberty.

GnRH are hypothalamic hormones

LH acts at the Leading cells and stimulates synthesis and secretion of androgens.

In Hindi

Puberty kay time gonadotropin releasing hormone ka secretion bhut jaida Hota Hai parinaam Swaroop spermatogenesis start Hota Hai

GnRH ak hypothalamic hormone hai

LH leading cells per act karta hai Aur androgen Ka secretion Aur synthesise bhi karta hai

Androgens, in turn, stimulate the process of spermatogenesis. FSH acts on the Sertoli cells and stimulates secretion of some factors which help in the process of spermatogenesis.

Explain above paragraph

In English

  • Androgen stimulates the method of spermatogenesis
  • FSH act on the sertoli’s cell

Sperm Parts



Middle piece


In Hindi

  • Androgen spermatogenesis process ko stimulate karta hai
  • FSH hormone sertoli cell per act karta hai

Iet us examine the structure of a sperm. It is a microscopic structure composed of a head, neck, a middle piece and a tail (Figure A.2). A plasma membrane envelops the entire body of sperm. The sperm head contains an elongated haploid nucleus, the anterior portion of which covered by a cap-like structure, acrosome.  

Explain above paragraph

In English

  • Sperm is microscopic stracture
  • It is composed of a head, neck,a middle piece and a tail
  • Plasma membrane covered the whole body of sperm
  • It’s head contains an elongated haploid nucleus
  • It has a cap like stracture called acrosome

In Hindi

  • Sperm ak microscopic stracture hai
  • Yeh head,neck,middle piece and tail se milke bana hai
  • Sperm ki puri body plasma membrane se covered hoti hai
  • Eska ak lambasa haploid nucleus hota hai
  • Eska ak cup like stracture hota hai jese acrosome khate hai

The acrosome is full of with enzymes that help fertilisation of the ovum. The center piece (middle piece) possesses numerous mitochondria, which produce energy for the movement of tail that facilitate sperm motility essential for fertilisation. 

Explain above paragraph

In English

  • Acrosome has enzymes
  • The enzymes helps in fertilization of the ovum
  • The middle piece possesses many mitochondria
  • Mitochondria produced energy for the movement of tail
  • The tail facilitate sperm motility that essential for fertilization

In Hindi

  • Acrosome mai enzyme bhare hote hai
  • Aur oh enzymes ovum ke sath fertilization mai help krta hai
  • Sperm ka middle part mai bhut sare mitochondria hote hai
  • Aur ah mitochondria energy pardan karta hai jisse sperm ka tail ka movements hota hai
  • Aur ah tail sperm motility ko suwidha layek banata hai jo fertilization ke lie jroori hota hai

The human male ejaculates about 200 to 300 million sperms during a coitus of which, for normal fertility, a minimum of 6o percent sperms ” must have normal shape and size and a minimum of  40 percent of them must show vigorous motility.Sperms released from the seminiferous tubules, are transported by the accessory ducts

Explain above paragraph

In English In Hindi

  • In normal human male 200-300 million sperms ejaculates during a coitus
  • At least 60% percent sperms normal shape and size and 40% show vigorous motility
  • Sperms released from the seminiferous tubules
  • It transported by the accessory ducts
  • Ek normal purush mai sexual activity ke time 200-300 million sperms nikalta hai
  • Lagbhag 60% sperms ka shape aur size normal hota hai aur 40% vigorous(furtila) motility hoti hai
  • Sperms seminiferous tubules se nikalta hai
  • Ah accessory ducts se transported hota hai

Secretions of epididymis,vas deferens,seminal vesicle and prostate are essential for maturation and motility of sperms.The seminal plasma together with the sperms constitute the semen ” male sex accessory ducts and glands are maintained by-the testiculari hormones (androgens)  

Explain above paragraph

In English In Hindi

  • Epididymis,vas deferens,seminal vesicle and prostate are secretes which are necessary for maturation and motility of sperms
  • Semen is fluid composed of seminal plasma with sperms
  • Male sex accessory ducts and glands are maintained by the testicular hormones(androgen)
  • Epididymis,Vas deferens,seminal vesicle aur prostate ka secretion hota hai jo Maturation(pripakt) and motility of sperms ke liye bhut jroori hota hai
  • Semen ak fluid hai jo seminal plasma aur sperms ka apas mai milne se banta aai
  • Testicular hormones(androgen ) male sex accessory ducts aur galand ko maintained krta hai

Gametogenesis class 12 ncert: Oogenesis spermatogenesis in human reproduction,CBSE
Diagrammatic view of entire process of Spermatogenesis Fig A.1

Gametogenesis class 12 ncert part 1 male gametogenesis has completed above,now turn to 2nd part

Female (gametogenesis)

The process of formation of a mature female gamete is called  oogenesisi  which is marked by different from spermatogenesis.

Oogenesis is initiated during the embryonic developmept stage when couple of millon gamete mother cells (oogonia) are formed with in each fetal ovary, no more oogonia are formed and added after birth. 

Explain above paragraph

In English In Hindi

  • Oogenesis is a process by which a mature female gamets are formed
  • It’s process is different from spermatogenesis
  • Oogenesis begins during the embryonic development stage
  • During this stage million gamete mother cells(oogonia) are formed
  • No more oogonia are formed and added after birth
  • Oogenesis ek parkirya hai jo mature egg ka nirman karta hai
  • Oogenesis ki process spermatogenesis ki process se different hota hai
  • Oogenesis ki surwat embryonic development stage ke duran hi start ho jata hai
  • Embryonic development stage ke duran lakho gamete mother cells (oogonia )ka nirman hota hai
  • Birth ke baad kisi trah ki oogonia na banta hai aur nahi jorta hai

Do you know pregnancy and embryonic development ?

These cells start division and enter into prophase-I of the meiotic division and get temporarily arrested at that stage called primary oocytes.  

Explain above paragraph

In English

  • Oogonia starts division and enter into prophase -I of meiotic division
  • It get temporarily arrested at that stage called primary oocytes

In Hindi

Oogonia cells division krna start krne lagta hai phir meiotic division ke prophase-I mai enter ho jata hai

Aur ah temporarily es stage mai arrested ho jata hai jise primary oocytes kha jata hai

Each primary oocyte then gets surrounded by a layer of granulosa cells and is called the primary follicle (Figure A.3).A large number of these follicles degenerate during the phase from birth to puberty. Therefore, at puberty only 60.000-80.000 primary follicles are left in each ovary. 

Explain above paragraph

In English

  • Each primary oocyte surrounded by a layer of granulosa cells which is called primary follicle
  • Large number of these follicles degenerate during the phase from birth to puberty.
  • At the puberty only 60,000-80,000 primary follicles are left in each ovary.

In Hindi

  • Partek primary oocyte granulosa cells se ghere rahta hai aur ese primary follicle kha jata hai
  • Birth se puberty stage tak bari tadat mai ah follicles degenerate ho jata hai
  • Puberty stage mai each ovary mai 60,000-80,000 tak primary follicles hota hai

The primary follicles get surrounded by more layers of granulosa cells and a new theca andare called secondary follicles.” The secondary follicle soon transforms into a tertiary follicle which is characterised by a fluid filled cavity called antrum.

Explain above paragraph

In English

  • The primary follicles get surrounded by more layers of granulosa cells and a new theca which are called secondary follicles
  • The secondary follicles soon transfer into a tertiary follicles
  • The tertiary follicles have a fluid cavity called antrum

In Hindi

  • Primary follicles bhut sare granulosa cells player se ghere hote hai aur ak new theca banta hai jise secondary follicles kaha jata hai
  • Secondary follicles bhut jald tertiary follicles mai transfer ho jata hai
  • Tertiary follicles mai fluid cavity hote hai jise antrum kha jata hai

The theca layer is organised into an inner theca interna and an outer theca-externa. It is important to draw your attention that it is at this stage that the primary oocyte within the tertiary follicle grows in size and completes its first meiotic division. 

Explain above paragraph

In English

  • The theca layer has two parts inner one interna and outer one externa
  • At this stage the primary oocyte within the tertiary follicle grows in size and completed its first meiotic division

In Hindi

  • Theca layer ke two parts banjate hai ander wale part ko interna aur bahar wale ko externa kahte hai
  • Es stage mai primary oocyte tertiary follicle ke sath hi enke size barne lagta hai aur first meiotic division ko pura karta hai

 It is an unequal division leading to the formation of a big or( large) haploid secondary oocyte and a small first polar body (figureA.1 a). secondary oocyte retains bulk of nutrient rich cytoplasm of the primary (first )oocyte.

At present we aren’t very certain about this. The tertiary follicle further changes into the mature follicle or Graafian follicle (Figure A.3)

Explain above paragraph

In English

  • It(meiotic division) is an unequal division leading to the formation of a oversize haploid secondary occyte and little first polar body
  • Secondary Oocyte arrest bulk of nutrient rich cytoplasm of primary oocyte
  • The tertiary follicle further become turn the mature follicle or Graafian follicle

In Hindi

  • Ah ek unequal division hai jiske falsorop large haploid secondary oocyte aur first polar body ka nirman hota hai
  • Secondary oocyte mai primary oocyte ka nutrients wali cytoplasm ka bulk(gudda) bani rahti hai

Tertiary follicle, mature follicle ya Graafian follicle mai change ho jata hai

The secondary oocyte forms a  new membrane named zona pellucida surrounding it.  The Graafian follicle now ruptures to release the secondary oocyte( ovum) from the ovary by the method of ovulation

Explain above paragraph

Gametogenesis class 12ncert, oogenesis,spermatogenesis
Diagrammatic view of Oogenesis Fig A.2

In English

  • The secondary oocyte forms a new membrane called zona pellucida surrounding it
  • The graafian follicle now ruptures to release the secondary oocyte(ovum)from the ovary by process of ovulation

In Hindi

  • Secondary oocyte ak new membrane ka nirman karta hai jise zona pellucida kahte hai aur secondary oocyte ke charo traf gheere rahte hai
  • Ab Graafian follicles tutene lagte hai taki secondary oocyte(ovum) ovary se release ho sake aur ah puri process ko ovulation kaha jata hai

Gametogenesis class 12 ncert MCQ

1 Capacitation refers to the change in the

(a) ovum before fertilization

(c) sperm after fertilization

(b) ovum after fertilization

(d) sperm before fertilization

2 The process of releasing the ripe female gamete (ovum) from the ovary is called

(a) Parturition

(c) Fertilization

(b) Ovulation

(d) Implantation

3 In which phase of cell division is oogonia arrested

(a) Anaphase II

(c) Interphase

(b) Prophase I

(d) Both prophase I and IIA

4 Germ cells in mammalian gonads are produced by

(a) only mitosis

(c) Mitosis and meiosis both

(b) Only meiosis

(d) Without cell division

5 The breakage of the membrane surrounding the acrosome in a mammalian sperm is

(a) Activation

(b) Agglutination

(b) Cavitation

(d) Capacitation

6 How many secondary spermatocytes will be requird to form 400 spermatozoans

(a) 100

(c) 40

(b) 200

(d) 400

7 2n=16 in a primary spermatocyte whic is in metaphase of firs meitotic division. What shall be the total number of chromatids in each of the secondary spermatocyte

(a) 32

(c) 16

(b) 8

(d) 24

8 1st polar body is formed at which stage of oogenesis

(a) 1st meiosis

(c) 1st mitosis

(b) 2nd mitosis

(d) Differentiation

9 In oogenesis haploid egg is fertilized by sperm at which stage

(a) Primary oocyte

(c) Oogonium

(b) Secondary oocyte

(d) Ovum

10 Spermatide are transformed into spermatozoa by

(a) Spermiation

(c) Meiosis

(e) Spermiogenesis

(b) Spermatogenesis

(d) spermatosis

11 In frog chromosome no. is reduced to half

(a) When 2nd polar body is separated

(c) When 2nd polar body is divided

(b) When 3rd polar body is separated

(d) When 1st polar body is separated

12 Nebenkern is a part of

(a) Foetus

(c) Human ovum

(b) Graafian folicle

(d) Human sperm

13 In mammalian sperm , spirally arranged mitochondria are present in

(a) Head portion

(c) End piece of the tail

(b) Middle piece

(d) Principal piece of tail

14 Acrosome of sperm is formed from

(a) Nucleus of spermatid

(c) Golgi complex of spermatid

(b) Mitochondria of spermatid

(d) Controsome of spermatid

15 Sperm’s acrosome has

(a) Hyaluronic acid and proacrosine

(c) Hyaluronic acid and fertilizin

(b) Hyaluronidase and proacrosin

(d) Fertilizin and proacrosin

16 A cross section at the midpoint of the middle piece of a human sperm will show

(a) centriole, mitochondria and 9+2 arrangement of microtubules

(c) Mitochondria and 9+2 arrangem

(b) Centriole and mitochondria

(d) 9+2 arrangement of microtubles only

17 Which of the following cells during gametogenesis is normally diploid

(a) Spermatid

(c) Secondary polar body

(b) Spermatogonia

(d) Primary polar body

18 Sperms fromed from 4 primary spermatocytes are

(a) 4

(c) 16

(b) 1

(d) 32

19 Hormone responsible for metamorphosis in tadpole is

(a) Adrenaline

(c) Aldasterone

(b) thyroxine

(d) Vasopressin

20 What do you mean by the term spermateleosis

(a) Conversion of spermatids to sperm

(c) Conversion of spermatid to spermogonium

(b) conversion of spermogonium to spermatid

(d) Conversion of primary spermatocyte to secondary

21 Spermatogonia formed after whic cell division

(a) Meiosis I

(c) Mitosis

(b) Meiosis II

(d) Amitosis

22 Match the following with correct combination


(b)Corpus luteum

(c) Gastrulation

(d) Capactiation

(e) Colostrum

(1) Acrosomal reaction

(2) Morphagenetic movements

(3) Progesterone

(4) Mammary gland

(5) Sperm activation

(A) (a)-(5) , (b)-(2) , (c)-(4) , (d)-(1) , (e)-(3)

(B) (a)-(1) , (b)-(3) , (c)-(2) , (d)-(5) , (e)-(4)

(C) (a)-(1) , (b)-(2) , (c)-(3) , (d)-(4) , (e)-(5)

(D) (a)-(4) , (b)-(2) , (c)-(v) , (d)-(3) , (e)-(1)

Answer sheet Gametogenesis class 12 ncert

1-d 2-b 3-b 4-c 5-d 6-b 7-c 8-a 9-b 10-e 11-d 12-d 13-b 14-c 15-c 16-c 17-b 18-c 19-b 20-a 21-c 22-b

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Pregnancy and embryonic development ncert class 12

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