The 'Urey-Miller experiment' synthesized which organic molecules?
A. Lipids
B. DNA
C. Proteins
D. Amino acids
Answer: Option D
Solution (By JKExamLibrary)
Stanley Miller and Harold Urey simulated early Earth conditions and obtained amino acids (like glycine and alanine) by applying electric discharge to a mixture of gases.
Explanation:
Metabolism is the sum of all chemical reactions occurring in a living body. It is the only feature present in all living organisms without exception. While growth and reproduction are common, they are not universal (e.g., sterile mules). Non-living things can also exhibit growth by accumulation or movement, making metabolism the true defining property.
The hormone aldosterone, which acts on the distal convoluted tubule and collecting duct to increase sodium reabsorption and potassium excretion, is secreted by the:
Explanation:
Aldosterone is a mineralocorticoid hormone secreted by the zona glomerulosa, the outermost layer of the adrenal cortex. Its primary function is to regulate electrolyte balance by promoting the active reabsorption of sodium (Na+) and the excretion of potassium (K+) and hydrogen ions (H+) in the distal tubules and collecting ducts of the kidneys. The zona fasciculata secretes glucocorticoids (cortisol).
Explanation:
Energy pyramids are always upright because energy decreases at higher trophic levels. Pyramids of numbers and biomass can be inverted (e.g., tree ecosystem, aquatic).
No comments yet. Be the first to start the discussion!