The 'Hormone Prolactin' is secreted by the anterior pituitary gland. Its primary physiological role is to:
A. Stimulate the development of mammary glands and the production of milk (lactogenesis)
B. Trigger ovulation
C. Maintain the corpus luteum
D. Stimulate uterine contractions
Answer: Option A
Solution (By JKExamLibrary)
Prolactin (PRL) is a peptide hormone secreted by the lactotroph cells of the anterior pituitary gland. Its primary and namesake function is to stimulate the development of the mammary glands during pregnancy and to initiate and maintain the production of milk (lactogenesis) after childbirth. While prolactin levels rise significantly during pregnancy, the high levels of estrogen and progesterone inhibit actual milk secretion until after delivery. Suckling by the infant is the primary stimulus for continued prolactin release.
Explanation:
Lactase hydrolyzes lactose (milk sugar) into glucose and galactose. Lactose intolerance is due to lactase deficiency. Sucrase acts on sucrose, maltase on maltose.
Explanation:
Vitamin B₆ exists in three forms: pyridoxine, pyridoxal, and pyridoxamine. Its active form, pyridoxal phosphate (PLP), is a coenzyme in amino acid metabolism and neurotransmitter synthesis. Deficiency can cause peripheral neuropathy and anemia.
Explanation:
Prokaryotic cells contain 70S ribosomes, which are composed of a 50S large subunit and a 30S small subunit. The 'S' stands for Svedberg units, a measure of sedimentation rate. Eukaryotic cytoplasm contains 80S ribosomes, though their mitochondria and chloroplasts contain 70S ribosomes.
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