Molecular Biology

Step 1: Understanding the functions of RNAs.
- snRNA is involved in RNA splicing (P-2).

- piRNA is involved in germline protection from transposable elements (Q-4).

- snoRNA is involved in rRNA processing (R-1).

- siRNA is involved in selected mRNA degradation (S-3).

Step 2: Analyzing the options.
(A) P-4, Q-3, R-1, S-2: Incorrect — Some pairings are incorrect.
(B) P-4, Q-1, R-3, S-2: Correct — Some pairings are incorrect. This pairing correctly matches the RNA types with their functions.
(C) P-3, Q-2, R-1, S-4: Incorrect — Some pairings are incorrect.
(D) P-2, Q-4, R-1, S-3: Incorrect — This pairing correctly matches the RNA types with their functions.

Step 3: Conclusion.
The correct answer is (D) P-2, Q-4, R-1, S-3

Epinephrine, also known as adrenaline, is synthesized from the amino acid tyrosine. Other options like estradiol, progesterone, and testosterone are steroid hormones derived from cholesterol.

Ribozymes are RNA molecules with catalytic activity, capable of cleaving RNA and participating in RNA splicing. They are distinct from proteins with enzymatic activity

RNA is composed of ribonucleotides, each containing a ribose sugar, a phosphate group, and a nitrogenous base (adenine, uracil, cytosine, or guanine). This structure forms the backbone of RNA, enabling its various functions in cells, including protein synthesis.

Ribosomal RNA (rRNA) constitutes about 80% of the total RNA in a cell. It is a key component of ribosomes, where protein synthesis occurs. In contrast, messenger RNA (mRNA) and transfer RNA (tRNA) make up smaller proportions and serve as intermediaries in protein synthesis.

Okazaki fragments are short DNA segments synthesized on the lagging strand during replication. DNA ligase plays a critical role by sealing nicks between these fragments to form a continuous DNA strand. Other enzymes like helicase and primase have distinct roles, such as unwinding DNA and synthesizing primers, respectively