NEET Biology Human Reproduction MCQs Set 19

Answer: (a) The fertilized egg is placed in the womb of the mother where the gastrula period is completed

Explanation:
1. To produce test tube baby, the egg fertilized outside the human body, is placed in the womb of the mother, where the gastrula period is completed.

Answer: (b) Zona pellucida

Explanation:
1. The mature ovum or female gamete is spherical in shape. The human ovum is almost free of yolk and said to be alecithal. Its cytoplasm is called ooplasm containing large nucleus. The cytoplasm is enveloped by plasma membrane. Very small cortical granules are present under the plasma membrane.
2. A narrow perivitelline space is present outside the plasma membrane. Just outer to perivitelline space, there is thick non-cellular zona pellucida, secreted by follicular cells. Outer to the zona pellucida there is very thick cellular corona radiate.
3. The latter is formed of radially elongated follicular cells. The side of ovum which extrudes polar bodies is termed animal pole. The opposite side is called vegetal pole. Human ouvm loses its ability to be fertilized about 24 hours after ovulation. In human beings ovum is released from ovary as secondary oocyte

Answer: (b) Mature RBCs

Explanation:
1. The chromatin material inside the nucleus is composed of DNA, some proteins and RNA. Thus, in an enucleated ovum, DNA will be present in mitochondria.
2. The mature RBCs, lack nucleus and membrane bound cell organelles, i.e., lack DNA in nucleus and mitochondria.

Answer: (c) Neck and centriole

Explanation:
1. In the neck of human sperm there are pair of centriole. They also eter with nucleus in the ovum. Rest of sperm left behind. The first division in zygote takes place due to that centrioles. They form spindle fibre for first cell division

Answer: (d) All of the above

Explanation:
1. Sperm lysins contains hyaluronidase, corona penetrating enzyme, acrosin etc.
2. There are many enzymes in the acrosome like fertilisin, hyaluronidase, pectin corona penetrating enzyme, acrosin etc., together they are called sperm lysins

Answer: (a) Ampulla

Explanation:
1. It is very necessary to reach the sperm at the ampullary region because, it is the site where ova waits for sperm for two days after ovulation. That’s way all intercourse does not lead to fertilization

Answer: (a) Bartholin’s gland

Explanation:
1. Bartholin’s gland in female is the counterpart of Cowper’s gland in male. The secretion of this gland is thick, viscid and alaline for lubrication during copulation and counteracting urinary acidity.

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

Explanation:
1. Karyogamy and amphimixis are the same terms. Mixing up of chromosomes of male and female nucleus is called karyogamy or amphimixis

Answer: (a) Secretory phase

Explanation:
1. Luteal phase is also called secretory phase.
2. Generally, menstrual cycle have four phases
3. (i) Menstrual phase (a) The soft tissue of endometrial lining of the uterus disintegrates causing bleeding.
4. (b) The unfertilized egg and soft tissue are discharged.
5. (c) It lasts 3-5 days.
6. (ii) Follicular Phase/Proliferative Phase (a) The primary follicles in the ovary grow and become a fully mature Graafian follicle.
7. (b) The endometrium of the uterus is regenerated due to the secretion of LH and FSH from anterior pituitary and ovarian hormone, estrogen.
8. (c) It least for about 10-14 days.
9. (iii) Ovulatory Phase (a) Rapid secretion of LH (LH surge) induces rupture of Graafian follicle, thereby leading to ovulation (release of ovum).
10. (b) It lasts for only about 48 hr.
11. (iv) Luteal Phase/Secretor Phase (a) In this phase the ruptured follicle changes into corpus luteum in the ovary and it begins to secrete the hormone progesterone.
12. (b) The endometrium thickens further and their glands secrete a fluid into the uterus.
13. c) If ovum is not fertilized, the corpus luteum undergoes degeneration and this causes disintegration of the endometrium leading to menstruation

Answer: (b) Allantois

Explanation:
1. Allantois is an extra embryonic membrane developed as an outgrowth from hindgut. In the eggs of reptiles and birds, it functions as a urinary bladder and stores the waste excretory products. It also provides oxygen (in reptiles, birds and mammals) and food (in mammals) to the embryo.

Answer: (b) In the second cleavage division, one of the two blastomeres usually divides a little sooner than the second

Explanation:
1. During embryonic development of human, in the second cleavage division, one of the two blastomeres usually divides a little sooner then the second. Cleavage is series of mitotic cell divisions that increase the number of cells but does not change the size of the original mass.

Answer: (b) A-ectoderm, B-mesoderm, C-endoderm

Explanation:
1. A-Ectoderm, B-Mesoderm, C-Endoderm

Answer: (d) 6th month

Explanation:
1. 6th month.
2. Summary of important development changes in the human embryo

Answer: (b) The menstrual fluid can easily clot

Explanation:
1. During normal menstruation approximately 40 mL of blood and an additional 35 mL of serous fluid are lost. The menstrual fluid is normally non-clotting because a fibrinolysin is releasted alongwith necrotic endometrial material.

Answer: (b) Holoblastic and unequal

Explanation:
1. In mesolecithal eggs, moderate amount of yolk is present. Cleavage found in mesolecithal eggs are holoblastic and unequal, e.g., frog, Petromyzon, etc.

Answer: (a) Organs

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

Answer: (b) Trophoblast

Explanation:
1. After one week of fertilization, implantation begins to starts. During implantation, the trophoectoderm (trophoblast) comes in contact with the endometrium of the uterus and sinks into a pit formed in the endometrium and gets completely burried in the endometrium.

Answer: (b) Prostate

Explanation:
1. The male reproductive system, prostate gland is a single, large gland. It is situated around the first part of the urethra. It secretes a thin, milky fluid that contains calcium, citrate ion, phosphate ion, a clotting enzyme and a profibrinolysin.

Answer: (a) Inter digital space

Explanation:
1. Region outside the seminiferous tubules is called interdigital space, which is lined by interstitial cells also called Leydig cells. Leydig cells secretes testosterone and also called endocrine part of the testis

Answer: (a) Parturition

Explanation:
1. The process of giving birth to a baby or delivery of foetus is called parturition. It starts with rise in oestrogen/progesterone ratio, increase in the level of oxytocin secretion by both mother and foetus.

Answer: (c) Spermatogonium

Explanation:
1. The cuboidal cells in germinal epithelium undergo mitosis to produce spermatogonia which grows into primary spermatocytes. These in turn undergoes meiosis producing haploid cells, firstly secondary spermatocytes and then spermatids. The latter get converted into spermatozoa (sperms). Sertoli cells provides nutrition to the developing sperms

Answer: (c) Secondary oocyte

Explanation:
1. Ovulation (release of egg or ovum from ovary into body cavity) involves the extrusion of a secondary oocyte from the ovary. Actually by 10-14 days after the first day of menstruation, only one follicle has contained its growth to become a fully mature Graafian follicle, while other follicles regress through a process called follicle atresia. Under proper hormonal stimulation, Graafian follicle rupture and extrude its oocyte into the uterine tube in the process of ovulation.

Answer: (a) Sweat gland

Explanation:
1. Mammary glands are modified sweat glands that lie over the pectoral muscle. They occur in all female mammals and in a rudimentary from in all male mammals. In the human female, the mammary glands start to increase in size at puberty because of fat accumulation and reach their maximum development in approximately the twentieth year. These undergo additional development during pregnancy essential function of mammary gland is milk production which has nutritive and immunologic properties.

Answer: (a) Glandular

Explanation:
1. The glandular tissue comprises about 15-20 lobes in each breast. Each lobe is made up of number of lobules.
2. Each lobule is composed of grape like cluster of milk secreting glands termed as alveoli. When milk is produced, it passes from alveoli into mammary lobules and into the mammary ducts

Answer: (d) All of the above

Explanation:
1. In the ovulatory phase, both LH and FSH attain a peak level in middle of cycle (about 14 day). Rapid secretion of LH induces rupturing of Graafian follicle and thereby releasing the ovum in human beings (secondary oocyte is released). This is called ovulation. Infact increase level of LH causes ovulation