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Fertilization in human being - class-X

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Passage of ova through female reproductive tract is facilitated by 

  1. Ciliary movement

  2. Amoeboid movement

  3. Flagellar movement

  4. Cyclosis


Correct Option: A
Explanation:

The fallopian cells have cells lined with small hair-like structures called cilia that enable movement of the ovum to the uterus via ciliary movement. 

So, the correct answer is 'Ciliary movement'.

The second maturation division of the mammalian ovum occurs

  1. shortly after mutation before the ovum makes entry into the Fallopian tube

  2. Until after the ovum has been penetrated by a sperm

  3. Until the nucleus of the sperm has fused with that of the ovum

  4. In the Graafian follicle following the first maturation division


Correct Option: B
Explanation:
During oogenesis, primary oocyte grows and completes meiosis I (first maturation division) producing a large secondary oocyte and a small polar body. The secondary oocyte proceeds with meiosis II (second maturation division) but the diyision gets arrested at metaphase stage. It is in this stage of oocyte that the ovum is shed during ovulation. It passes into oviduct, where the cell cycle resumes only after the entry of sperm.
So, the correct answer is 'Until after the ovum has been penetrated by a sperm'.

Level of follicle stimulating hormone (FSH) during infancy and adulthood is the same but spermatogenesis is seen only during adulthood. mRNA levels coding for FSH receptors are also found to be same in testis of both age groups. Which of the following investigations will clarify this paradox a little more?

  1. Culture testcular cells and add to see testosterone production.

  2. Culture testicular cells and add testosterone to see comparative rise in FSH mRNA from both age groups.

  3. Culture testicular cells and FSH to see comparative rise in cAMP production by both age groups.

  4. Add both LH and FSH to testicular cells and evaluate cAMP production.


Correct Option: A
Explanation:

In males, FSH and LH are secreted by hypothalamus. FSH stimulates Sertoli cells of the testes to secrete androgen binding protein (ABP) that concentrates testosterone in seminiferous tubules. LH stimulates interstitial cells (leydig's cells) of the testes to secrete androgens testosterone. Androgens stimulate germinal epithelium to undergo spermatogenesis.

Arrange the following stages of fertilisation and early development into a proper sequence.
I. Sperm entry
II. Acrosomal reaction
III. Karyogamy
IV. Capacitation
V. Cortical reaction

  1. I, III, II, IV, V

  2. III, V, I, IV, II

  3. IV, II, V, I, III

  4. V, I, IV, II, III


Correct Option: A
Explanation:
Fertilization can be described as the following steps:
1. Sperm Capacitation. 
2. Sperm-Zona Pellucida Binding. 
3. The Acrosome Reaction. 
4. Penetration of the Zona Pellucida. 
5. Sperm-Oocyte Binding.
6. Egg Activation and the Cortical Reaction. 
7. The Zona Reaction.
8. Post-fertilization Events.
So, the correct option is 'I, III, II, IV, V'.

Which of the following events occur in the part of human reproductive system? 

  1. Fertilisation

  2. Implantation

  3. Both of them

  4. None of them


Correct Option: C
Explanation:

  • Fertilization is the process of the fusion of the male and the female gamete. This process takes place in the ampullary region of the fallopian tube. 
  • The implantation is the process of attachment of the fetus to the wall of the uterus. Both of these events occur in the parts of the female reproductive system. 
Thus, the correct answer is option C. 

Zygote is formed by the process of

  1. Anisogamy

  2. Isogamy

  3. Oogamy

  4. Syngamy


Correct Option: D
Explanation:

The process of fusion between a haploid male nucleus and an egg nucleus is known as amphimixis. It is also known as syngamy or fertilization which leads to formation of a diploid zygote. It leads to the recombination of character which causes variation. It is a mode of sexual reproduction.

A single sperm fuses with the ova and releases its nuclei and cellular contents in the ovum. The condition when the multiple sperm fuses with a single ovum is known as polyspermy.
So, the correct answer is option D.

Fertilization is the fusion of sperm and ovum.

  1. True

  2. False


Correct Option: A
Explanation:

Fertilization is the fusion of male and female gametes to initiate the development of a new individual by the formation of diploid cell i.e., the zygote.  In mammals including humans, fertilization is internal, takes place inside the human body.
Thus, the correct answer is option A.

Fertilization occurs in human, rabbit and other placental mammals in

  1. Ovary

  2. Uterus

  3. Fallopian tubes

  4. Vagina


Correct Option: C
Explanation:

In most mammals fertilization of the ovum takes place in the fallopian tubes. After fertilization initial process of cell division occurs in the fallopian tube that leads to the formation of the morula and blastula stage. After this Blastula enters the uterine cavity (the inside of the uterus).

When was the first test tube baby born?

  1. 2 January 1981

  2. 25 July 1978

  3. 3 August 1975

  4. 4 February 1982


Correct Option: B
Explanation:
World's First Test Tube Baby Born. On this day in 1978. Louise Joy Brown, the world's first baby to be conceived via in vitro fertilization (IVF) is born at Oldham and District General Hospital in Manchester, England, to parents Lesley and Peter Brown. So, the correct option is "B"25 July 1978.

Fertilization in humans is practically feasible only if

  1. the ovum and sperms are transported simultaneously to ampullary - isthmic junction of the fallopian tube

  2. the ovum and sperms are transported simultaneously to ampullary - isthmic junction of the cervix

  3. the sperms are transported into cervix within $48$ hours of release to ovum in uterus

  4. the sperms are transported into vagina just after the release of ovum in fallopian tube.


Correct Option: A
Explanation:
Ampulla averages 5–8 cm in length. It is within this highly ciliated portion of the oviduct that fertilization and early embryo development occur. The ampulla is most often also the site for ectopic implantation (ectopic pregnancy). The next region, approximately 2–3 cm in length, is the isthmus. Like the ampulla, it too is ciliated yet less densely so. The isthmus is thought to regulate sperm and embryo transport.
So, the correct option is 'the ovum and sperms are transported 'simultaneously to ampullary - isthmic junction of the fallopian tube'

The process of union of male gamete with egg cell is called ________.

  1. Fertilization

  2. Pollution

  3. Double fertilization

  4. Germination


Correct Option: A
Explanation:

The process in which union of male and female gametes (formed by gametogenesis) and fusion of pronuclei of sperm and egg (ovum) takes place is called fertilization. The resultant product of fertilization is called zygote 

Which of the following is a correct sequence of events that occur in human reproduction? 

  1. Gametogenesis $\rightarrow$ Gestation $\rightarrow$  Insemination $\rightarrow$ Fertilisation $\rightarrow$ Implantation $\rightarrow$ parturition

  2. Gametogenesis $\rightarrow$Insemination$\rightarrow$ Fertilisation $\rightarrow$ Implantation $\rightarrow$ Gestation $\rightarrow$ parturition

  3. Gametogenesis $\rightarrow$ Insemination$\rightarrow$ Gestation $\rightarrow$ Fertilisation $\rightarrow$ Implantation $\rightarrow$ parturition

  4. Gestation $\rightarrow$ Gametogenesis $\rightarrow$ Insemination  $\rightarrow$ Implantation $\rightarrow$ Fertilisation $\rightarrow$ parturition


Correct Option: B
Explanation:

The sequence of events occurring in case of Human reproduction are:

Gametogenesis is the process of formation of gametes from germ cells.
Insemination is the deposition of semen containing sperm into the vagina of female.

Fertilisation is the process of fusion of male and female gametes for the formation of zygote.
Implantation is the process of embedding of formed zygote after fertilisation into the endometrium of the uterus.
Gestation is the process of development of the foetus inside the uterus till till it is fully developed to be delivered.
Parturition is the process of delivery of fully formed foetus.
So, the correct answer is 'Gametogenesis $\rightarrow$ Insemination $\rightarrow$ Fertilisation $\rightarrow$ Implantation $\rightarrow$ Gestation $\rightarrow$ Parturition'.

In which one of the following parts of the female reproductive system  fertilization takes place? 

  1. Uterus

  2. Oviduct

  3. Vagina

  4. Ovary

  5. None of these


Correct Option: B
Explanation:

the site of fertilization ( union of male of female gametes) in human beings is in the Fallopian tube/ Oviduct ( specifically the ampullary-isthmic junction) in the female reproductive tract.

So, the correct option is 'Oviduct'.

State true or false

 
(i) A zygote is always formed inside the body.
(ii) Zygote may represent "overwintering stage" in life cycle of an organism

  1. True

  2. False


Correct Option: B
Explanation:
A zygote is formed inside the body if the fertilization is internal and it can also develop outside the body if the fertilization is external. Overwintering stage is the process by which some organisms pass through or wait out the winter season. But zygote does not represent the overwintering stage in the life cycle of the organism.
So the correct answer is 'False'.

All copulations do not lead to fertilization and pregnancy because?

  1. All mating does not result in transport of sperm and ovum simultaneously at ampulla

  2. Survival duration of both sperm and ovum is same

  3. Number of sperms and ovum varies

  4. None of these


Correct Option: A
Explanation:
All copulation does not lead to fertilization and pregnancy because all mating does not result in transport of sperm and ovum simultaneously at ampulla.
The ovum has to be present in the ampulla of fallopian tube, so when the sperm reaches, it fertilizes and causes pregnancy.
It is very important for sperm and ovum to be present at the same time in ampulla, to cause fertilization and pregnancy.
Correct Answer -[A] option.

A human zygote has 

  1. 46 chromosomes

  2. 23 chromosomes

  3. 47 chromosomes

  4. 48 chromosomes


Correct Option: A
Explanation:

Zygote or the fertilized egg cell results from the union of a female gamete (Egg or ovum) with a male gamete (sperm). The number of chromosomes in the gamete is haploid and human gametes contain 23 chromosomes. As zygote is from the fusion of two gametes, the chromosome number is diploid and is double of that in gamete and thus has 46 chromosomes.

The number of nuclei present in a zygote is 

  1. None

  2. One

  3. Two

  4. Four


Correct Option: B
Explanation:

A zygote is a cell formed when two gamete cells are fused by means of sexual reproduction. Here, the sperm nucleus fuses with the egg nucleus to form a single zygote nucleus.
Thus, the correct answer is option B.

A new human individual develops from a cell called as gamete.

  1. True

  2. False


Correct Option: B
Explanation:

A gamete is a haploid cell that fuses with another cell during fertilization in organisms and results in the formation of a diploid zygote. This zygote is the earliest developmental stage of embryo form which the organism develops.
Thus, the correct answer is option B.

A zygote is formed as a result of fertilization.

  1. True

  2. False


Correct Option: A
Explanation:

A zygote is a diploid cell that is formed by the fusion of male and female haploid gamete cells. The process of fusion of gametes is known as fertilisation
So, the correct answer is 'True'

Egg laid after fertilization is diploid.

  1. True

  2. False


Correct Option: A
Explanation:

Fertilisation is the fusion of male and female gametes with the mixing of the 23 male and 23 female chromosomes. The zygote has 46 chromosomes so they are diploid in nature.
Thus, the correct answer is option A.

The process of releasing of sperm by male organism during copulation is called as

  1. Ejaculation

  2. Insemination

  3. Fertilization

  4. Parturition


Correct Option: A
Explanation:

Ejaculation is the discharge of semen, usually carrying sperms from the male reproductive tract during copulation.
Insemination is the introduction of a sperm into a female for fertilization.
Fertilization is the fusion of male and female gametes.
Parturition is the action of giving birth to young ones.
Thus, the correct answer is option A.

An embryo is made up of a single cell.

  1. True

  2. False


Correct Option: B
Explanation:

  • Zygote is a unicellular structure formed from fusion of male and female gametes.
  • Zygote undergoes cell differentiation and cell division (mitosis) to form embryo.
  • Embryo is multicellular structure.
So, the correct option is 'False'.

The embryo is formed by the fusion of

  1. Male gametes

  2. Male and female gametes

  3. Female gametes

  4. Spores and gametes


Correct Option: B
Explanation:

The embryo is an unborn or unhatched offspring in the process of development. It results from sexual reproduction, where there is a fusion of male and female gametes.
Thus, the correct answer is the option (B), 'Male and female gametes'.

The only haploid stage in an animal life cycle is the

  1. Zoospores

  2. Spores

  3. Gametes

  4. None of the above


Correct Option: C
Explanation:

A zoospore is a motile asexual spore that uses a flagellum for locomotion.
Spores are formed by certain fungi and algae, in response to unfavorable growing conditions.
A gamete is a reproductive cells that unite at fertilization to form a new cell (zygote). This gamete is haploid in nature.
Thus, the correct answer is option C.

What is formed immediately after fertilisation?

  1. Placenta

  2. Foetus

  3. Embryo

  4. Zygote


Correct Option: D
Explanation:

Zygote is the fertilized egg, that results from the union of a female gamete (egg or ovum) with a male gamete (sperm) by a process called fertilization.
Placenta is an organ that connects the developing fetus to the uterine wall.
Foetus is the state between the embryonic stage and birth.
The embryo is about five weeks old (or from 7th week of pregnancy).
Thus, the correct answer is option D.

The hormone responsible for inducing spermatogenesis and oogenesis is

  1. FSH

  2. Estrogen

  3. LH

  4. Androgen


Correct Option: A
Explanation:
  • Gonadotrophin regulating hormone (GnRH) secreted by the hypothalamus stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in male. 
  • FSH enters the testes stimulating the Sertoli cells which help to nourish the sperm cells that the testes produce to begin the process of spermatogenesis. Similarly in females, GnRH secreted by the hypothalamus stimulates the release of FSH, which stimulates the growth of egg cells, and LH, which signals for the ovulation of an egg from its follicle. 

The hormone responsible for inducing spermatogenesis and oogenesis is 

  1. FSH

  2. Estrogen

  3. Testosterone

  4. Androgen


Correct Option: A
Explanation:

  • FSH or follicle stimulating hormone is a pituitary hormone.
  • It induces oogenesis in females by inducing development of Graafian follicle from the primordial follicle.
  • In males, it induces spermatogenesis by inducing primary spermatocytes to undergo the first division of meiosis, to form secondary spermatocytes.
So, the correct option is 'FSH'.

Select out the incorrect statement(s).
A. The zygote undergoes a series of meiotic divisions called cleavage.
B. The zygote is implanted in blastocyst stage on to the uterine wall.
C. The rhythmic contractions of muscles in the uterus occur in the presence of progesterone.
D. The stoppage of menstruation is called menopause.

  1. A only

  2. C and D

  3. A and C

  4. B and D


Correct Option: C
Explanation:

The zygote undergoes series of mitotic divisions to form new cells and the process is known as cleavage. The zygote at the blastocyst stage is implanted into the uterine wall. The contractions of muscles in the uterus during parturition occurs in the presence of oxytocin. The period when the menstrual cycle stops is known as menopause.

Thus, the correct answer is option C. 

Uterus receives foetus from oviduct

  1. True

  2. False

  3. Ambiguous

  4. Data insufficient


Correct Option: B

During fertilization the nucler of the sperm and egg form two different nucleus

  1. True

  2. False

  3. Ambiguous

  4. Data insufficient


Correct Option: B

The first step in the process of fertilization is development of zygote 

  1. True

  2. False

  3. Ambiguous

  4. Data insufficient


Correct Option: B

Fertilization result in the formation of embryo 

  1. True

  2. False

  3. Ambiguous

  4. Data insufficient


Correct Option: B

Fertilization takes places in uterus

  1. True

  2. False

  3. Ambigous

  4. Data insufficient


Correct Option: B

In humans, successful fertilization takes place in

  1. Ovary

  2. Fallopian tube

  3. Uterus

  4. Cervix

  5. Vagina


Correct Option: B
Explanation:
  • During copulation (coitus) semen is released by the penis into the vagina (insemination). 
  • The motile sperms swim rapidly, pass through the cervix, enter into the uterus and finally reach the ampullary region of the fallopian tube.
  • The ovum released by the ovary is also transported to the ampullary region of fallopian tube where fertilisation takes place. 
  • So, the correct option is 'Fallopian tube'.

On fertilization of egg nucleus with sperm nucleus 

  1. First maturation is completed

  2. Second maturation is completed

  3. Embryo is formed

  4. First polar body is formed


Correct Option: C
Explanation:

When the egg nucleus and the sperm nucleus unites in the fallopian tube, it results in fertilization. And it results in the production of zygote or fertilized egg. Maturation is completed during the the gametogenesis (before the formation of egg / sperm) and the polar body is also formed during this process.
Thus, the correct answer is option C.

On fertilization of egg nucleus with sperm nucleus

  1. Second maturation is completed

  2. Zygote is formed

  3. First polar body is formed

  4. First maturation is completed


Correct Option: B
Explanation:

Fertilization occurs when the nucleus of both, a sperm and an egg fuse to form a diploid cell, known as a zygote. A zygote is a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum. An organism in the early stages of growth and differentiation, from fertilization to the beginning of the third month of pregnancy (in humans) is called as an embryo, after that, an embryo is called a fetus.

Fertilization of ovum occurs in

  1. Fimbriae of oviduct

  2. Isthmus of oviduct

  3. Ampulla of oviduct

  4. None of the above


Correct Option: C
Explanation:

During copulation, semen is released by the penis into the vagina. The motile sperms swim rapidly, pass through the cervix, enter into the uterus and finally reach the junction of the isthmus and ampulla of the fallopian tube. the ovum released by the ovaries also transported to the ampullary-isthmus junction where fertilization takes place.

So, the correct option is 'Ampulla of oviduct'.

Is the chromosome number of the zygote, embryonal cells, and adult of a particular organism always constant? How is the constancy maintained in these three stages?

  1. Yes, by mitosis

  2. Yes, by meiosis

  3. No, by meiosis

  4. No, by mitosis


Correct Option: A
Explanation:

  • A zygote is the fertilized egg that results from the union of male and female gametes. Once, the zygote is formed, 
  • it undergoes mitotic divisions. Embryonal cells also divide by mitosis to produce more of its kind. The cells in the adult organism also divide by mitosis.
Mitosis is a type of cell division in which the chromosomes in a cell nucleus are separated into two equal sets of chromosomes, each in its own nucleus.

Thus, the correct answer is option A.

What would be the ratio of chromosome number between an egg and its zygote? 

  1. 1 : 2

  2. 2 : 2

  3. 1 : 3

  4. 2 : 1


Correct Option: A
Explanation:

The egg is the female gamete and is haploid in nature containing 'n' number of chromosomes. Zygote is formed by the fusion of male and female gametes and is thus diploid in nature and contains '2n' number of chromosomes.
Thus, the correct answer is option A.

Which of the following lead to pregnancy and development of embryo.
(i) Fertilization of egg
(ii) Maturation of egg
(iii) Release of egg
(iv) Embedding of embryo in thickened uterine wall.
Which of the following options gives the correct order of sequence in which they occur?

  1. (i), (ii), (iii), (iv)

  2. (ii), (i), (iii)(iv)

  3. (i), (iv), (ii), (iii)

  4. None of the above


Correct Option: D
Explanation:

After ovulation only matured eggs can be fertilized in reproduction. After fertilization at blastocyst stage implantation occurs in uterine wall and development of embryo takes place. Thus, the correct answer is option D.

After fertilisation, the resulting cell which gives rise to a new individual is the

  1. Embryo

  2. Ovum

  3. Foetus

  4. Zygote


Correct Option: A
Explanation:

After fertilization, male and female gametes fuse to form a zygote. The zygote undergoes changes to form an embryo having two cells. Then there are successive divisions in embryo and formation of morula and blastula occurs. The embryo gives rise to a new individual. The embryo undergoes organogenesis and forms a new individual.

So, the correct answer is option A.

In human beings, the correct sequence of events during reproduction is

  1. Gamete formation, fertilisation, zygote, embryo

  2. Embryo, zygote, fertilisation, gamete formation

  3. Fertilisation, gamete formation, embryo, zygote

  4. Gamete formation, fertilisation, embryo, zygote


Correct Option: A
Explanation:

Sexual reproduction is the process wherein gametes both from male and female fuse together to give rise to a new progeny.
Steps involved in sexual reproduction :

  • Male gametes are produced in male reproductive organ by the process called spermatogenesis in semeniferous tubules in gonads and female gametes are produced in female reproductive organ by the process called oogenesis in the ovaries. This process is called gametogenesis.
  • The sperm (male gamete) enters the ovum (female gamete) by rupturing the cell wall of ovum and releases its chromosomal material in the ovum. This process is called fertilization. Wherein the egg is fertilized by a sperm.
  • Fertilisation process brings together two sets of chromosome, one from female and one from male. Thereby forming a diploid cell called zygote. Hence called zygote formation.
  • The newly formed zygote undergoes many cycles of cell division passing the stages from morula, blastula and giving rise to a multicellular structure called embryo through the process called embryogenesis.

Zygote is formed by

  1. Fusion of two cells

  2. Fusion of gametes

  3. Fusion of only chloroplast portion of gametes

  4. Fusion of polar cells


Correct Option: B
Explanation:

Zygote or the fertilized egg is the diploid cell that is formed from the fusion of a female gamete (ovum) with a male gamete (sperm). Zygote is the universal diploid cell. The zygote undergoes cleavage to form the embryo. Thus, the correct answer is option B.

Which of the following statements about reproduction in the human being is correct?

  1. Fertilisation takes place in ovary.

  2. Fertilisation takes place in the testes.

  3. During fertilisation egg moves towards the sperm.

  4. Fertilisation takes place in the human female (oviduct).


Correct Option: D
Explanation:

Fertilization that takes place inside the female body is called internal fertilization. In human fertilization takes place in the oviduct. During fertilization motile sperm moves towards egg and fuse to form the zygote. Thus, the correct answer is option D.

How does fertilization take place?

  1. Egg released from the ovary reaches the oviduct.

  2. Sperm encounters egg in the oviduct and fertilization takes place.

  3. Sperm encounters egg in the vagina and fertilization takes place.

  4. Sperm enters through the vaginal passage.


Correct Option: B
Explanation:

Fertilization is the process of fusion of human egg and sperm. Where sperm enters through vagina and encounters the ovum for fusion in fallopian tube During fertilization acrosome reaction takes palce between the zona pallucida membrane and enzyme in acrosome. Thus, the correct answer is option B.

Our government has legalized the age of marriage in boys and girls. Give reasons as to why one should get married after a certain age.

  1. For sexual and mental maturation

  2. For mental maturation

  3. For psychological maturation

  4. For financial maturation


Correct Option: A
Explanation:

  • After a certain age, An individual becomes sexually and mentally mature. After that age an individual becomes adults.
  •  According to the Indian Government marriage should be after maturity of individuals. Prohibition of Child Marriage Act states that a girl in India can't marry before the age of 18, and a boy before 21 yrs. 

Thus, the correct answer is option A.

Which of the following is the correct sequence?

  1. $Gametogenesis \rightarrow Syngamy \rightarrow Embryogenesis \rightarrow Zygote$

  2. $Gametogenesis \rightarrow Syngamy \rightarrow Zygote \rightarrow Embryogenesis$

  3. $Syngamy \rightarrow Gametogenesis \rightarrow Embryogenesis \rightarrow Zygote$

  4. $Zygote \rightarrow Embryogenesis \rightarrow Syngamy \rightarrow Gametogenesis$


Correct Option: B
Explanation:

The male gamete is formed by spermatogenesis. The female gamete is formed by oogenesis. This process of formation of male and female gametes is called gametogenesis. Syngamy is a process in sexual reproduction that is defined as the fusion of the male gamete i.e., sperm with the female gamete i.e., egg resulting in the formation of a diploid zygote. Embryogenesis takes place eight weeks after fertilization. Thus the correct answer is option B.

The presence or absence of hymen is not reliable indicator of virginity or sexual experience.

  1. True

  2. False


Correct Option: B
Explanation:

The opening of the vagina is covered partially by a membrane called hymen. This membrane is often torn during the first coitus (intercourse). However, it can also be broken by a sudden fall or jolt, insertion of a vaginal tampon, active participation in some sports like horseback riding, cycling, etc. Moreover, in some women, the hymen persists even after coitus. Hence, the presence or absence of hymen is not a reliable indicator of virginity or sexual experience.

Fertilization takes place in

  1. Fallopian tube

  2. Follicle

  3. Uterus

  4. Vagina


Correct Option: A
Explanation:

The steps of fertilization in humans always involve the joining of an egg and sperm. In natural conception, the male sperm fertilizes the female egg inside the woman’s body. While many think fertilization occurs in the ovary, it actually takes place in the fallopian tube just outside the ovary. From there, the fertilized egg travels down the fallopian tube. If it successfully implants in the uterus, an embryo can begin to grow.

So the correct option is 'fallopian tube'.

By the fusion of male and female gametes ........... is formed.

  1. Zygote

  2. Embryo

  3. Seed

  4. Ovum


Correct Option: A
Explanation:
  • The fertilization process brings together two sets of chromosomes, one from female and one from the male.
  •  The fusion of male and female gametes leads to the formation of zygote. It has a diploid set of chromosomes. 
  • So, the correct answer is option A.

Sexually transmitted diseases can be prevented by using condoms.

  1. True

  2. False


Correct Option: A
Explanation:
  • Condoms are the barrier method of birth control. Use of condoms block the sperm from entering the uterus. 
  • Sexually transmitted diseases can be prevented by using condoms as they make a physiological barrier between two individuals and prevents the entry of sperm into the female body. 
  • Thus, the correct answer is option A.

Fertilization of egg takes place in uterus.

  1. True

  2. False


Correct Option: B
Explanation:

Fertilization is the fusion of male (sperm) and female gametes (ovum) and it takes place in the Fallopian tube. 
Therefore, the correct answer is option B.

If there is no formation of egg cell during the development of ovule, then after fertilization which of the following structure will not develop?

  1. Embryo

  2. Endosperm

  3. Seed

  4. Fruit


Correct Option: A
Explanation:

After fertilization in plant, ovule develops into the seed.  Fertilized egg get segmented and lined by the cell-membrane which forms plant-embryo. Thus, the correct answer is option A.

What happens during fertilization in humans after many sperms reach close to the ovum?

  1. Secretions of acrosome help one sperm enter cytoplasm of ovum through zona pellucida

  2. all sperms except the one nearest to the ovum lose their tails.

  3. cells of corona radiata trap all the sperms except one

  4. only two sperms nearest the ovum penetrate zona pellucida.


Correct Option: A
Explanation:

During the process of fertilisation of the male and the female gametes (i.e the sperm and the egg) in humans, the sperm cells reach the egg, binds through the corona radiata and reach the zona pellucida layer of the egg. Here a molecule on the sperm binds with a glycoprotein in the zona pellucida layer of the egg. This causes the acrosome to burst, releasing an enzyme that helps the sperm cells to cross the zona pellucida. Now the cortical granules in the secondary oocyte release their content. this causes the zona pellucida to cross-link and harden, thus preventing the fertilisation of the egg by more than one sperm by preventing the entry of the sperm. Therefore, only a single sperm cell penetrates the zona pellucida. So, the correct option is 'Secretions of acrosome help one sperm enter the cytoplasm of ovum through zona pellucida'.

For erection and ejaculation to occur.

  1. There must be sufficient blood hydrostatic pressure leading to erectile tissue

  2. The parasympathetic and sympathetic branches of the nervous system must be properly functioning

  3. The urinary sphincters must be closed

  4. All of the above


Correct Option: B

Which of the following would be the correct path of a sperm on its way to fertilize an egg?
(i) Urethra
(ii) Epididymis
(iii) Vagina
(iv) Oviduct
(v) Vas deferens

  1. (i), (ii), (iii), (v), (iv)

  2. (i), (iii), (iv), (v), (ii)

  3. (ii), (i), (iii), (iv), (v)

  4. (ii), (v), (i), (iii), (iv)


Correct Option: D
Explanation:

  • Sperms are produced in seminiferous tubules.
  • From seminiferous tubules, they pass via seminiferous tubules-------> rete testis------> vasa efferentia--------> epididymis--------> vas deferens----------> urethra.
  • After ejaculation in the vagina, they pass through cervix and uterus to finally reach oviduct.
So, the correct option is '(ii), (v), (i), (iii), (iv)'.

At the time of fertilization

  1. First maturation division is completed

  2. Embryo is formed

  3. Second maturation division is completed

  4. First polar body is formed.


Correct Option: C
Explanation:

When the sperm cell penetrates into the ovum, second maturation division occurs.

So the correct option is 'Second maturation division is completed.'

Fertilization in humans is practically feasible only if

  1. The sperms are transported into cervix within $48$ hours of release of ovum in uterus

  2. The sperms are transported into vagina just after the release of ovum in fallopian tube

  3. The ovum and sperms are transported simultaneously to ampullary-isthmi junction of fallopian tube

  4. The ovum and sperms are transported simulatenously to ampullary-isthmi junction of cervix.


Correct Option: A
Explanation:

Fertilization in humans is practically feasible only if the sperms are transported into the cervix within 48 hours of the release of an ovum in the uterus. This is because the ovum is present in the fallopian tube in this duration and starts degrading after this.

So, the correct answer  is 'The sperms are transported into cervix within 
4848 hours of the release of the ovum in uterus'.

In human beings, after fertilisation, the structure which gets embedded in the wall of uterus is

  1. Ovum

  2. Embryo

  3. Blastocyst

  4. Zygote


Correct Option: C
Explanation:

After fertilization zygote is formed. Zygote start moving towards uterus and initial development takes place. Zygote enters the uterus on 3rd day in morula stage and later develops into blastocyst that implants in uterus wall. Thus, the correct answer is option C.

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