NEET Biology Human Reproduction MCQs Set 16

Answer: (a) Make uterus unsuitable for implantation

Explanation:
1. Intra Uterine Device (IUD) is a small device made up of copper, plastic or stainless steel. It is inserted into uterus by a doctor and left in place. It prevents implantation and may cause bleeding and discomfort.

Answer: (a) Attachment of blastocyst to uterine wall

Explanation:
1. Implantation is the attachment of blastocytes to the uterine wall.
2. Gametes. The major reproductive events in human beings are as follows
3. (i) Gametogenesis It is the formation of gametes. It includes spermatogenesis (formation of sperms) and oogenesis (formation of ova/eggs)
4. (ii) Insemination It is the transfer of sperms by the male into the genital tract of the female
5. (iii) Fertilization Fusion of male and female gametes to form zygote is called fertilization
6. (iv) Cleavage It is rapid mitotic divisions of the zygote which convert the single celled zygote into a multicellular structure called blastocyst (blastula)
7. (v) Implantation It is the attachment of blastocyst to the uterine wall
8. (vi) Placentation It involves the formation of placenta which is the intimate connection between the foetus and uterine wall of the mother to exchange the materials
9. (vii) Gastrulation It is the process by which blastocyst is changed into gastrula with three primary germ layers
10. (viii) Organogenesis It is the formation of specific tissue, organs and organ systems from three primary germ layers
11. (ix) Parturition (child birth) it involves expelling of the baby from the mother’s womb (uterus)

Answer: (d) Insects

Explanation:
1. The amount of yolk determines the type of cleavage in the egg. In superficial meroblastic cleavage, the cleavage remains restricted to the peripheral portion of the egg. This type of cleavage occurs in arthropods especially insects.
2. i.e., centrolecithal eggs.

Answer: (d) Menarch

Explanation:
1. Menarche.
2. Menstrual Cycle
3. (i) The rhythmic series of changes that occurs in the reproductive organs of female primates (monkeys, apes and human beings) is called menstrual cycle.
4. (ii) It is repeated at an average interval of about 28/29 days.
5. The first appearance of menstruation at puberty is called menarche

Answer: (a) A-primary sex organs; B-secondary sex organs

Explanation:
1. A-Primary sex organs; B-Secondary sex organs

Answer: (a) 4-5 cm and 2-3 cm

Explanation:
1. Each human testis is oval in shape with a length of about 4 to 5 cm and a width of about 2 to 3 cm

Answer: (a) Golgi bodies

Explanation:
1. The anterior portion of sperm head is covered by a cap-like structure, called acrosome. Acrosome is formed from the Golgi complex. It contains digestive enzyme hyaluronidase and proteinase. Acrosome plays an important role in penetration of ovum by sperm during fertilization.

Answer: (c) A-primary; B-ovarian hormones

Explanation:
1. A-primary; B-ovarian hormones

Answer: (b) Development of corpus luteum

Explanation:
1. Development of corpus luteum is done by progesterone and LH not by FSH. Progesterone and LH are secreted by anterior lobe of pituitary

Answer: (d) Seminiferous tubules

Explanation:
1. Each lobule of testis contains two to three seminiferous tubules, blood vessels, nerves and connective tissue. Wall of each seminiferous tubule is formed of a single layered germinal epithelium. Majority of cells in this epithelium are cubical, however at certain places, there are present large pyramidal Sertoli or nurse cells. Sertoli cells nourish the developing sperms.

Answer: (c) Development of corpus luteum – Secretory phase and increased secretion of progesterone

Explanation:
1. In secretory phase during ovulation, the follicle breaks and collapse under the continuous influence of Luteinizing Hormone (LH). It begins to enlarge and forms a yellowish structure, called the corpus luteum. The corpus luteum plays an important role in the preparation of the endometrium for the implantation of the fertilized egg by secreting estrogens and progesterone.

Answer: (b) Help in collection of the ovum after ovulation

Explanation:
1. The part of the Fallopian tubes (oviducts) closer to the ovary is the funnel-shaped infundibulum. The edges of the infundibulum possess finger-like projections called fimbriae, which help in collection of the ovum after ovulation

Answer: (c) A-vas deferens; B-urinary bladder

Explanation:
1. A-vas deferens; B-urinary bladder

Answer: (d) All of the above

Explanation:
1. All of the above.
2. Placenta release oestrogens, progesterone, \(\mathrm{hCG}\) and relaxin. That’s why it can be considered as endocrine gland

Answer: (a) Graafian follicle

Explanation:
1. After ovulation, frog Graafian follicle acts as an endocrine gland because it secretes progesterone hormone for the maintenance of pregnancy.

Answer: (a) Testes

Explanation:
1. Testes.
2. Differences between primary and secondary sex organs

Answer: (c) Both (a) and (b)

Explanation:
1. In parturation there is strong uterine contraction leads to the expulsion of baby called child birth

Answer: (c) Seminiferous tubules and provide nutrition to germ cells

Explanation:
1. The epithelium of seminiferous tubule is made up of two types of cells- Sertoli’s cells and spermatogenic cells. Sertoli’s cells nourish spermatozoa, act as nurse cells for differentiating spermatozoa phagocytize defective sperm and secrete protein hormone inhibin (which inhibits FSH secretion).

Answer: (a) Acrosome

Explanation:
1. In the given options only acrosome belong to the male reproductive system. Rest of the options (corpus luteum, endometrium, Graafian follicle) belongs to the female reproductive system

Answer: (d) Telohase-I

Explanation:
1. Ovary is internally differentiated into four parts, i.e., outer germinal epithelium of cubical cells, a delicate sheath of connective tissue or tunica albuginea, a cortex of dense connective tissue with reticular fibres, spindle-shaped cells, ovarian follicles and a few blood vessels while the central part of medulla is made of less dense connective tissue with elastic fibres, smooth muscles, a number of blood vessels and a few nerves.
2. Maturation of secondary oocyte is completed in mother’s oviduct after the sperm entry into it for fertilization. \(2°\) oocyte stops advancing further after the completion of metaphase-II. Sperm entry restart the cell cycle by breaking down MPF (Maturation Promoting Factor) and truning on APF (Anaphase Promoting Factor)

Answer: (c) Interstitial cells

Explanation:
1. The target of Interstitial Cell Stimulating Hormone (ICSH) is the interstitial cell. Interstitial cells produces testosterone which is responsible for the development of secondary sexual characters

Answer: (a) A-Chorion; B-Placenta

Explanation:
1. A-Chorion; B-Placenta

Answer: (a) Fertilization

Explanation:
1. The fusion of a haploid male gamete (sperm) and a haploid female gamete (ovum) to form zygote is called fertilization. Fertilization takes places in fallopian tube of human.

Answer: (c) Ampullary isthmic junction

Explanation:
1. Fertilization takes place in ampulla of oviduct or ampullary isthmic junction

Answer: (c) 1:4

Explanation:
1. One ovum is produced from one germ cell of female gonad, whereas four sperms are produced from one germ cell of male gonad. Thus, the ratio of ova and sperms will be 1 : 4.