The hormone that stimulates the release of growth hormone from the pituitary is:
A. Growth hormone-releasing hormone (GHRH)
B. Cortisol
C. Dopamine
D. Somatostatin
Answer: Option A
Solution (By JKSSB Mock Tests)
GHRH, from the hypothalamus, stimulates the anterior pituitary to secrete growth hormone. Somatostatin inhibits GH release. Dopamine inhibits prolactin.
Explanation:
Sucrose (table sugar) is a disaccharide composed of glucose and fructose. Glucose and fructose are monosaccharides, glycogen is a polysaccharide. Other disaccharides include maltose and lactose.
Explanation:
Abscisic acid (ABA) is a stress hormone that induces stomatal closure by causing efflux of K⁺ ions from guard cells, leading to loss of turgor, thereby reducing water loss during drought. Auxin and cytokinin promote growth, gibberellin stimulates stem elongation and seed germination. ABA also promotes seed dormancy and leaf senescence.
Explanation:
The lac repressor protein (product of lacI gene) binds to the operator sequence, preventing RNA polymerase from transcribing the structural genes. When lactose is present, allolactose (inducer) binds the repressor, causing it to release the operator, allowing transcription. This is negative regulation.
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