NEET Biology Human Reproduction MCQs Set 42

Answer: (c) mesoderm

Explanation:
1. The gonads (testes and ovaries) develop from the intermediate mesoderm of the embryo.

Teacher's Note:
1. Mesoderm forms muscle, bone and gonads.
2. Ectoderm forms the nervous system.

Answer: (c) 2

Explanation:
1. A secondary spermatocyte divides by meiosis II to form two spermatids, which become two sperms.
2. A primary spermatocyte gives four.

Teacher's Note:
1. One primary spermatocyte gives four sperms.
2. One secondary spermatocyte gives two.

Answer: (c) testis — testosterone

Explanation:
1. Leydig cells (interstitial cells) lie between the seminiferous tubules of the testis.
2. They secrete testosterone under the influence of LH.

Teacher's Note:
1. Leydig cells are the male hormone factories.
2. Sertoli cells nourish the sperms.

Answer: (a) LH

Explanation:
1. The mid-cycle surge of luteinising hormone (LH) triggers ovulation.
2. FSH only helps the follicle to grow.

Teacher's Note:
1. LH surge causes ovulation.
2. It also forms the corpus luteum.

Answer: (c) 14 day

Explanation:
1. In a 28 day menstrual cycle, ovulation takes place on about the 14th day.
2. The follicular phase precedes it and the luteal phase follows.

Teacher's Note:
1. Counting starts with the first day of menstruation.
2. The corpus luteum forms after ovulation.

Answer: (c) FSH, LH, estrogen

Explanation:
1. The menstrual cycle is controlled by FSH, LH and the ovarian hormones estrogen and progesterone.
2. No single hormone controls it, so the best answer includes FSH, LH and estrogen.

Teacher's Note:
1. Hypothalamus, pituitary and ovary work together.
2. Estrogen peaks before ovulation.

Answer: (b) Rete testis to epididymis

Explanation:
1. The vasa efferentia are fine ductules that carry sperms from the rete testis to the epididymis.
2. The epididymis then leads to the vas deferens.

Teacher's Note:
1. Sperm path: seminiferous tubules, rete testis, vasa efferentia, epididymis, vas deferens.
2. Learn the order.

Answer: (a) Meiocyte

Explanation:
1. Meiosis occurs in a meiocyte (a cell that undergoes meiosis), e.g. spore mother cell or primary spermatocyte.
2. Conidia and gemmules are formed by mitosis.

Teacher's Note:
1. Meiocytes are diploid cells.
2. They form haploid gametes or spores.

Answer: (d) Spermatogonia, spermatocyte, spermatid, spermatozoa

Explanation:
1. Sperm formation (spermatogenesis) is: spermatogonia, primary spermatocyte, secondary spermatocyte, spermatid and spermatozoa.

Teacher's Note:
1. Spermiogenesis converts spermatids into sperms.
2. Meiosis occurs at the spermatocyte stage.

Answer: (b) partial/parietal

Explanation:
1. Meroblastic cleavage is a partial (incomplete) cleavage that occurs in yolk-rich eggs, as in birds.
2. Holoblastic cleavage is total.

Teacher's Note:
1. Meroblastic means partial.
2. It occurs in eggs with much yolk.

Answer: (a) ectoderm

Explanation:
1. The lens of the eye develops from the surface ectoderm.
2. Retina and the optic nerve come from the brain (neural ectoderm).

Teacher's Note:
1. Lens is an ectodermal derivative.
2. Cornea epithelium is also ectodermal.

Answer: (b) unequal holoblastic HUMAN REPRODUCTION : HUMAN EMBRYOLOGY

Explanation:
1. Mammalian eggs have little yolk and divide completely but unequally, giving a few large and many small cells (unequal holoblastic).

Teacher's Note:
1. Holoblastic means complete division.
2. Unequal cells form the blastocyst.