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407 questions in this collection · Page 20 of 41
Chemical Coordination And Integration
Chemical Coordination And Integration
| Column-I | Column-II |
|---|---|
| (A)Pituitary gland | (I)Grave's disease |
| (B)Thyroid gland | (II)Diabetes mellitus |
| (C)Adrenal gland | (III)Diabetes insipidus |
| (D)Pancreas | (IV)Addison's disease |
AI-generated explanation. Check against your textbook.
Match: Pituitary gland – Diabetes insipidus (III) due to ADH deficiency; Thyroid gland – Grave's disease (I) as a common hyperthyroidism; Adrenal gland – Addison's disease (IV) from adrenal insufficiency; Pancreas – Diabetes mellitus (II) due to insulin deficiency or action. Therefore the correct pairing is (A)-(III), (B)-(I), (C)-(IV), (D)-(II).
NCERT explains that pituitary hormones regulate water balance, thyroid hormones regulate metabolism, adrenal cortex hormones regulate stress and metabolism, and pancreatic insulin regulates blood glucose.
Pituitary—diabetes insipidus; Thyroid—Grave’s disease; Adrenal—Addison’s disease; Pancreas—diabetes mellitus.
Chemical Coordination And Integration
Reproduction In Organisms
AI-generated explanation. Check against your textbook.
In Agave, the vegetative propagule is called a bulbil. A bulbil is a small bulb-like shoot that forms on the plant and can develop into a new plant when separated. This concept is described in NCERT under vegetative propagation, where bulbil formation is noted for certain plants like Agave. The other options are different structures: a rhizome is an underground stem; an offset is a small plant produced at the base of the parent (common in some aquatic or succulent plants); an eye is a bud or a part of a stem that can give rise to a new shoot. Thus bulbil is the correct term for Agave’s vegetative propagule.
Some plants produce plantlets or bulbils that can detach and grow elsewhere, aiding rapid propagation without seeds.
Bulbil is a type of vegetative propagule mentioned in NCERT to describe a bulb-like shoot that forms on the plant.
Reproduction In Organisms
Human Reproduction
| Column-I | Column-II |
|---|---|
| (A)Placenta | (I)Androgens |
| (B)Zona pellucida | (II)Human Chorionic Gonadotropin (hCG) |
| (C)Bulbo-urethral glands | (III)Layer of the ovum |
| (D)Leydig cells | (IV)Lubrication of the Penis |
Human Reproduction
AI-generated explanation. Check against your textbook.
Ovulation is triggered by a surge in luteinising hormone (LH) from the anterior pituitary, which is caused by a high level of estrogen released by the graphsian (mature) follicle as the follicular phase peaks. Thus, a high concentration of estrogen induces the LH surge leading to ovulation. The other options are incorrect: progesterone rises after ovulation, not before; low LH or low FSH does not trigger ovulation.
In the menstrual cycle, estrogen rises during the follicular phase and peaks just before ovulation, causing the LH surge that releases the egg.
Estrogen-induced LH surge leads to ovulation.
Human Reproduction
AI-generated explanation. Check against your textbook.
The secondary oocyte is arrested in metaphase II and completes meiosis II only after fertilization. When a sperm fuses with the ovum, the oocyte finishes meiosis II, forming the mature ovum and a second polar body. Hence, the meiotic division is completed at the time of fusion of a sperm with an ovum (option 4).
Fertilization triggers the last meiotic division, ensuring the haploid number is restored in the zygote.
The secondary oocyte completes meiosis II only upon fertilization, forming the mature ovum.
Human Reproduction
AI-generated explanation. Check against your textbook.
In meiosis, cells become haploid (n) after the first division or as gametes. Secondary spermatocyte is haploid (produced after meiosis I in spermatogenesis). The first polar body is also a haploid product of meiosis I. The ovum (egg) is a haploid gamete after meiosis. Thus all three in option 2 are haploid. Other options mix diploid and haploid cells (e.g., primary oocyte and spermatogonia are diploid; spermatid is haploid but not with the others in that group). Therefore option 2 is correct according to NCERT concepts of haploid cells in human gametogenesis.
During oogenesis, the first polar body divides or may not; in humans, the secondary oocyte completes meiosis II only after fertilization, producing the ovum and a second polar body.
Haploid cells contain a single set of chromosomes (n). In human gametogenesis, meiosis I and II produce haploid products such as secondary spermatocytes, polar bodies, and ova.
Human Reproduction
| Column-I | Column-II |
|---|---|
| (A)Ovary | (I)Human chorionic Gonadotropin |
| (B)Placenta | (II)Estrogen & Progesterone |
| (C)Corpus luteum | (III)Androgens |
| (D)Leydig cells | (IV)Progesterone only |