Exams › NEET › Biology › Human Reproduction
129 questions with worked solutions.
Answer: ectoderm
The eye lens develops from surface ectoderm, specifically the lens placode. Mesoderm mainly contributes to supportive tissues, while endoderm does not form the lens.
Q2. What is true for cleavage?
Answer: Size of cells decrease
During cleavage, the zygote undergoes rapid mitotic divisions with little or no overall growth. As a result, the embryo stays about the same size while individual cells become smaller.
Q3. Meiotic division of the secondary oocyte is completed
Answer: At the time of fusion of a sperm with an ovum
The secondary oocyte is arrested in metaphase II and only completes the second meiotic division when a sperm fuses with it. This fertilization-triggered completion produces the mature ovum and allows formation of the zygote afterward.
Q4. Which part of ovary in mammals acts as an endocrine gland after ovulation?
Answer: Graafian follicle
The Graafian follicle transforms after ovulation into the corpus luteum, which functions as an endocrine gland. It secretes hormones, especially progesterone, to support the uterine lining.
Q5. Mainly which type of hormones control the menstrual cycle in human beings?
Answer: FSH, LH, estrogen
The menstrual cycle is controlled by a hormonal feedback loop involving pituitary hormones and ovarian hormones. FSH and LH regulate follicle development and ovulation, while estrogen helps drive cycle changes in the uterus and feedback control.
Q6. Which of the following hormones is not a secretion product of human placenta?
Answer: Prolactin
The human placenta secretes hCG, estrogens, and progesterone to support pregnancy. Prolactin is primarily secreted by the anterior pituitary, so it is not a placental secretion product.
Q7. The mammalian corpus luteum produces
Answer: progesterone
The corpus luteum forms from the ruptured follicle after ovulation and its primary endocrine role is to secrete progesterone. Progesterone prepares and maintains the endometrium for possible implantation and pregnancy.
Q8. Ovulation is stimulated by
Answer: LH
Ovulation is triggered by the mid-cycle surge of luteinizing hormone (LH). This surge causes the mature follicle to rupture and release the egg.
Q9. Ovulation occurs under the influence of
Answer: LH
Ovulation is triggered by the LH surge from the anterior pituitary. FSH mainly supports follicle growth, while estrogen and progesterone regulate the cycle but do not directly cause ovulation.
Q10. Testosterone is produced by
Answer: leydig’s cells
Leydig cells in the testes produce testosterone in response to luteinizing hormone (LH). Sertoli cells mainly support spermatogenesis, while oxyntic cells and the pituitary gland are not the primary source of testosterone.
Q11. Male hormone is produced in the testis by cells of
Answer: leydig
Leydig cells are the interstitial cells of the testis that synthesize and secrete testosterone, the main male hormone. Sertoli cells mainly support and nourish developing sperm cells.
Q12. Occurrence of Leydig’s cells and their secretion is
Answer: testes and testosterone
Leydig cells are located in the testes, where they synthesize and secrete testosterone. This hormone is the primary androgen responsible for male secondary sexual characteristics and supports sperm production.
Q13. In an egg, the type of cleavage is determined by
Answer: amount and distribution of yolk
Cleavage in eggs depends on how much yolk is present and where it is concentrated, because yolk interferes with cell division. Eggs with little yolk divide more completely, while yolk-rich eggs show partial or uneven cleavage.
Q14. Study of formation, growth and development of new individual from an egg is
Answer: Embryology
Embryology is the branch of biology that deals with the formation, growth, and development of an organism from the egg stage. The other options refer to different concepts: apomixis is asexual seed formation, cytology is the study of cells, and embryogeny is the process of embryo formation rather than the study itself.
Q15. The shared terminal duct of the reproductive and urinary system in the human male is:
Answer: Urethra
The urethra is the shared terminal duct in males because it carries urine from the bladder and also semen during ejaculation. The ureter only carries urine from kidney to bladder, while vas deferens and vasa efferentia are sperm transport ducts only.
Answer: Female reproductive tract
Capacitation is the functional maturation of sperm that occurs in the female reproductive tract, where they become capable of undergoing the acrosome reaction and fertilizing the ovum. It does not occur in the male ducts like the epididymis, vas deferens, or rete testis.
Answer: Testes to epididymis
The vasa efferentia are the ducts that transport sperm from the testes into the epididymis. If they are blocked, sperm cannot move from the testes to the epididymis, so that is the interrupted route.
Q18. Vasa efferentia are the ductules leading from
Answer: rete testis to vas deferens
Vasa efferentia are the small ductules that transport sperm from the rete testis toward the epididymis, ultimately joining the pathway to the vas deferens. That makes the correct choice the route from rete testis to vas deferens.
Q19. Seminal plasma in human males is rich in :
Answer: fructose and calcium
Seminal plasma contains fructose, which provides energy for sperm motility, and calcium, which is commonly present in reproductive secretions and supports sperm function. The other options include molecules not typically rich in seminal plasma.
Answer: Maintaining the scrotal temperature lower than the internal body temperature
Spermatogenesis works best at a temperature slightly lower than normal internal body temperature. The scrotum keeps the testes cooler, which is essential for healthy sperm formation.