The 'Hormone Luteinizing Hormone' (LH) is secreted by the anterior pituitary. In females, the mid-cycle surge of LH directly triggers: MCQ with Answer and Explanation
The 'Hormone Luteinizing Hormone' (LH) is secreted by the anterior pituitary. In females, the mid-cycle surge of LH directly triggers:
A. The thickening of the uterine lining
B. The growth of ovarian follicles
C. Menstruation
D. Ovulation and the formation of the corpus luteum
Answer: Option D
Solution (By JKExamLibrary)
Luteinizing Hormone (LH) is a gonadotropin secreted by the gonadotroph cells of the anterior pituitary. In females, during the late follicular phase, rising estrogen levels exert positive feedback on the pituitary, causing a massive, sudden surge of LH (the LH surge). This surge directly triggers ovulation (the rupture of the mature Graafian follicle and release of the secondary oocyte) and subsequently stimulates the remaining follicular cells to transform into the corpus luteum, which secretes progesterone.
Explanation:
Cloning produces genetically identical copies of a DNA fragment (molecular cloning) or an entire organism (reproductive cloning). Hybridization is crossing different varieties, mutation is change in DNA, transformation is DNA uptake.
Explanation:
The pineal gland secretes melatonin in a daily rhythm, peaking at night, thus regulating the sleep-wake cycle and seasonal biological rhythms. The pituitary controls other glands, thyroid metabolism, adrenals stress response. Light signals from the retina influence pineal activity.
Consider statements about animal husbandry: 1. Silkworms feed on mulberry leaves. 2. Honeybees communicate through the waggle dance. 3. Fish farming is called sericulture. Which are correct?
Explanation:
The domesticated silkworm, Bombyx mori, is a monophagous insect that feeds exclusively on the leaves of the mulberry plant (Morus alba). Honeybees perform a 'waggle dance' on the honeycomb to communicate the direction and distance of food sources to other worker bees. Fish farming is called pisciculture or aquaculture; sericulture specifically refers to the rearing of silkworms for silk production. Thus, statements 1 and 2 are correct.
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