The 'Hormone Leptin' acts on the hypothalamus to regulate energy balance. It does this primarily by binding to receptors in the: MCQ with Answer and Explanation
The 'Hormone Leptin' acts on the hypothalamus to regulate energy balance. It does this primarily by binding to receptors in the:
A. Suprachiasmatic nucleus
B. Arcuate nucleus
C. Ventromedial hypothalamus
D. Lateral hypothalamus
Answer: Option B
Solution (By JKExamLibrary)
Leptin is a hormone secreted by adipose tissue that signals the status of body fat stores to the brain. It acts primarily on the arcuate nucleus (ARC) of the hypothalamus. The ARC contains two key populations of neurons: one that co-expresses Neuropeptide Y (NPY) and Agouti-related peptide (AgRP), which stimulate appetite, and another that expresses Pro-opiomelanocortin (POMC) and Cocaine- and amphetamine-regulated transcript (CART), which suppress appetite. Leptin binds to receptors on these neurons, inhibiting the NPY/AgRP neurons and stimulating the POMC/CART neurons, thereby reducing appetite and increasing energy expenditure.
Explanation:
Autotrophs (self-feeders) include photoautotrophs (plants, algae, cyanobacteria) and chemoautotrophs (some bacteria). They produce organic matter from CO₂. Heterotrophs depend on others, saprotrophs decompose dead matter, parasites live on hosts.
Explanation:
Glyoxysomes are specialized peroxisomes found in the fat-storing cotyledons of germinating seeds. They contain enzymes for the beta-oxidation of fatty acids and the glyoxylate cycle, which converts stored lipids into carbohydrates (gluconeogenesis) to nourish the growing seedling. This metabolic pathway is absent in animal cells. Exam tip: Glyoxysomes eventually transform into chloroplasts as the plant matures.
Explanation:
Thyroid-stimulating hormone (TSH) from the anterior pituitary binds to receptors on thyroid follicular cells, stimulating synthesis and release of thyroid hormones (T₃ and T₄). ACTH targets adrenal cortex.
No comments yet. Be the first to start the discussion!