NEET Biology Human Reproduction MCQs Set 07

Answer: (b) Capitation

Explanation:
1. Capacitation of Sperm The sperms in the female is genital tract are made capable of fertilizing the egg by the secretion of female genital tract. These secretions of the female genital tract removes the coating substances deposited on the surface of the sperms, particularly those on acrosome. Thus, the receptor sites on the acrosome are exposed and sperm become active to penetrate the egg. This phenomenon of sperm activation in mammals is called capacitation. It takes about 5-6 hr for capacitation of sperm

Answer: (d) Ovulation-LH and FSH attain last peak and sharp full in secretion of progesterone

Explanation:
1. In the ovulatory phase, production of FSH decreases, while that of LH increases it causes ovulation. The ovum is drawn into Fallopian tube

Answer: (d) A-FSH; B-oestrogen

Explanation:
1. A-FSH; B-Oestrogen

Answer: (a) Old man

Explanation:
1. Biological process of ageing is higher in human males than in females. Thus, dead space is highest in old men.

Answer: (c) A-depolarisaton; B-monospermy

Explanation:
1. Due to changing of the membrane potential, there is depolarization and due to depolarization the entry of other sperms is blocked. This leads to the monospermy

Answer: (b) A-seminal vesicles; B-urethra

Explanation:
1. A-seminal vesicles; B-urethra

Answer: (b) Vegetative propagation

Explanation:
1. Binary fission is a mode of vegetative reproduction, in which simple cell division takes place. The unicelled forms like diatoms, desmids, yeast, slime moulds, etc, multiply by this process.

Answer: (b) Haploid parthenogenesis

Explanation:
1. Parthenogenesis (Apomixis)
2. It is the development of a new individual from a single gamete (generally the egg/ovum) without involving fertilisation. On the basis of chromosomes sets, parthenogenesis is of two types(i) Arrhenotoky (haploid) parthenogenesis). Haploid eggs grow to form haploid males \(e.g.,\) arachnids, some insects. (ii) Thelytoky (diploid parthenogenesis). Diploid eggs grow without fertilisation into diploid individuals, generally females \(e.g.,\)Gall fly. Parthenogenesis can be natural or artificial. Natural parthenogenesis may be obligatory or cyclic.
3. Obligatory/Complete Parthenogenesis Males are absent. Females develop parthenogenesis, \(e.g.,\) rotifers, Typhlina brahmina (small lizard, 15 cm long),Lacerta saxicola armeniaca (caucasian rock lizard), Cnemidophorus (whiptail lizards of America).
4. Cyclic/IncompleteParthenogenesis Both sexual and parthenogenetic individuals occur. In aphids several generations of parthenogenetic females develop followed by formation of both male and females to perform sexual reproduction. In Turkey, 40% of the males develop parthenogenetically. In honeybee, male of drone develops parthenogenetically (no meiosis at the time of spermatogenesis) while queen and workers develop from fertilized eggs. Also in wasps and ants. In gall fly, larvae may lay eggs that develop parthenogenetically (paedogenesis)

Answer: (b) Archenteron is formed

Explanation:
1. Gastrulation is the formation of gastrula from blastula. It is that phase of embryonic development during which the cells of blastula move in small mass to attain the final location. Such movement of cells is called morphogenetic movement.

Answer: (a) High level of hormone in blood

Explanation:
1. Menstrual cycle do not takes place regularly because of high levels of hormones in the blood

Answer: (c) 16

Explanation:
1. In spermatogenesis, primary spermatocyte undergoes meiosis-I and as a result of which two haploid secondary spermatocytes formed. Thus, for the given case secondary spermatocyte possesses 8 chromosomes, i.e.,\(n\)=8 and 16 chromatids because each chromosome divides along its length into two chromatids.

Answer: (b) rete testes to vas deferens

Explanation:
1. Rete testis is connected to caput epididymis by 12-20 fine tubules called vasa efferentia or ductuli efference. These collect sperms from inside the testis and transfer them to the epididymis. Vas deferens arises from cauda epididymis, conducts, sperms from epididymis to urethra.

Answer: (b) Ovary

Explanation:
1. Corpus luteum is a yelloow glandular mass in the ovary formed by the cells of ovarian follicle that has matured and discharged its ovum.

Answer: (a) A-trophoblastic cell, B-corpus luteum, C-progesterone, D-endometrium, E-menstruation

Explanation:
1. A-Trophoblastic cell, B-Corpus luteum, C-Progesterone, D-Endometrium, E-Menstruation

Answer: (d) Spermatozoa

Explanation:
1. Spermatozoa contains a proteinaceous substances known as anti-fertillizin. It is a protein, which is composed of acidic amino acid.

Answer: (a) Animal pole

Explanation:
1. Ovum receives the sperm in the region of animal pole. The sperm fuses with ovum to form diploid zygote. The pole of ovum opposite to animal pole is coiled vegetal pole.

Answer: (c) After fusion of sperm and ova

Explanation:
1. Second meiotic division takes place in ova after sperm and ova fusion. Proximal convulated tubules and distal convulated tubules at the neck region in sperm helps to complete the 2nd meiotic division

Answer: (c) Sertoli’s cells, seminiferous tubules, Leydig’s cells,

Explanation:
1. Sertoli’s cells, seminiferous tubules and Leydig’s cells, all are present in testes, while Graafian follicles are present in ovary of mammals.

Answer: (c) Characterized by a yellow colour

Explanation:
1. Corpus luteum is the yellow endocrine body formed in the ovary at the site of a ruptured Graafian follicle, while macula lutea is a yellow spot on the retina. The common feature between the two is that both (corpus luteum and macula lutea) are characterized by yellow colour.

Answer: (c) Error and damages theories

Explanation:
1. Somatic mutation theory is a part of damage or error theories regarding the cause of ageing. It advocates that genetic mutations occur and accumulate with increasing age, causing cell to deteriorate and malfunction.

Answer: (a) Oxytocin

Explanation:
1. Among prostaglandin, oestrogen and oxytocin, it is oxytocin contract the uterine wall strongly.
2. Parturition
3. (i) The average duration of human pregnancy is about 9 months which is called the gestation period
4. (ii) The act of expelling the full term foetus from the mother’s uterus at the end of gestation period is called parturition
5. (iii) It is induced by a complex neuroendocrine mechanism
6. (iv) Parturition signals originates from the fully developed foetus and the palcenta, which induce mild uterine contractions called foetus ejection reflex
7. (v) This triggers the release of oxytocin from the maternal pituitary
8. (vi) Oxytocin induces stronger uterine muscle contractions
9. (vii) Relaxin increases the flexibility of the pubic symphysis and ligaments that helps to dilate the uterine cervix during labour pain
10. (viii) This leads to the expulsion of baby

Answer: (c) Nervous system

Explanation:
1. Nervous system consists of highly specialized cells called the neurons. The neurons defect and receive information from different sensory organs and integrate them to determine the mode of response of the body. Nervous system is ectodermal in origin.

Answer: (d) Inhibin

Explanation:
1. Inhibin is a glycoprotein hormone secreted from the Sertoli’s cells. It is involved in the negative feedback control of sperm production.

Answer: (c) IUDs (intra uterine devices)

Explanation:
1. At present, the most widely accepted method of contraception in India is IUDs (Intra Uterine Devices). These devices are effective and popuar. These devices are inserted by doctors and expert nurses in the uterus through vagina.

Answer: (c) Gynogenesis

Explanation:
1. Gynogenesis leads to non-participation of male pronucleus in fertilization.