Fertilization in human being - class-X

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. 

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.

• 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. 

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.

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.

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).

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 

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

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.

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.

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 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 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'

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.

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.

• 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.

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'.

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.

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.

• 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. 

• 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.

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.

The uterus does not receive the fetus from the oviduct; the oviduct (fallopian tube) transports the fertilized egg (zygote/embryo) to the uterus for implantation.

During fertilization, the haploid nuclei of the sperm and egg fuse to form a single diploid nucleus (the zygote nucleus), not two different nuclei.

The first step of fertilization is the penetration of the sperm into the egg, followed by the fusion of nuclei. The development of the zygote occurs after fertilization is complete.

Fertilization results in the formation of a single-celled zygote. The embryo is the developmental stage that follows subsequent cell divisions.

Fertilization typically takes place in the ampulla of the fallopian tube (oviduct), not in the uterus.

• 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'.

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.

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.

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.

• 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.

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.

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 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.

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 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.

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.

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.

• 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. 

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 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.

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.

• 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.

• 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 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.

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.

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'.

• 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.

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

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.

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.