The 'Hormone Insulin' is a peptide hormone composed of two polypeptide chains, A and B, linked by:
A. Hydrogen bonds
B. Ionic bonds
C. Disulfide bridges
D. Peptide bonds
Answer: Option C
Solution (By JKSSB Mock Tests)
Insulin is a peptide hormone produced by the beta cells of the Islets of Langerhans in the pancreas. It is initially synthesized as a single, inactive polypeptide precursor called proinsulin. During processing, a connecting peptide (C-peptide) is removed, leaving two polypeptide chains: the A chain (21 amino acids) and the B chain (30 amino acids). These two chains are held together by two interchain disulfide bridges (covalent bonds between sulfur atoms of cysteine residues), and there is also one intrachain disulfide bridge within the A chain.
Explanation:
Oleic acid is a monounsaturated fatty acid (one double bond), found in olive oil. Stearic acid is saturated, linoleic acid is polyunsaturated (two double bonds), linolenic acid is polyunsaturated (three double bonds). Unsaturated fats are generally liquid at room temperature and healthier for the heart. Oleic acid is an omega-9 fatty acid.
Explanation:
Autotrophs produce organic compounds from inorganic CO₂ and water using light energy (photosynthesis). This exactly defines green plants. So both are true, and R explains A.
Explanation:
Bacteria lack a true nucleus; their circular chromosome is concentrated in a region called the nucleoid. Plasmids are extra-chromosomal DNA but the main genome is in the nucleoid. Eukaryotes have a membrane-bound nucleus.
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