Q.20 In the process of exploring eukaryotic 80S ribosome, the following components may be observed:

1. 28S rRNA, 5.8S rRNA
2. 5S rRNA and 34 proteins
3. 23S rRNA
4. 5S rRNA and 49 proteins

Choose the correct answer from the options given below:

1. (A) and (D) only
2. (A) and (B) only
3. (A), (C) and (D) only

4. Eukaryotic 80S ribosomes consist of a 60S large subunit with 28S rRNA, 5.8S rRNA, 5S rRNA, and about 49 proteins, plus a 40S small subunit with 18S rRNA and about 33 proteins; thus, options (A) and (B) correctly describe components observable in the 80S ribosome, while (C) and (D) refer to prokaryotic 70S features.

   Correct Components

   • (A) 28S rRNA, 5.8S rRNA: These are core rRNAs in the eukaryotic 60S large subunit, essential for peptidyl transferase activity.

   • (B) 5S rRNA and 34 proteins: 5S rRNA is in the 60S subunit (~49 total proteins, with ~34 close approximation in some contexts); observable in eukaryotic ribosomes.

   • (C) 23S rRNA: This belongs to prokaryotic 50S subunits, not eukaryotic 80S.

   • (D) 5S rRNA and 49 proteins: Matches prokaryotic large subunit (23S + 5S rRNA + ~34 proteins, but listed as 49 in error); not eukaryotic-specific.

   Option Breakdown

   • (A) and (D) only: Incorrect; (D) is prokaryotic.

   • (A) and (B) only: Correct; both describe eukaryotic 60S elements.

   • (A), (C) and (D) only: Incorrect; (C) and (D) are prokaryotic.

   • (A), (B) and (C) only: Incorrect; (C) mismatches.

   Eukaryotic 80S ribosome components form a key topic in GATE Life Sciences and NEET exams, distinguishing them from prokaryotic 70S ribosomes. This matching question tests knowledge of rRNA and protein counts in the 60S and 40S subunits for protein synthesis. Master it with detailed breakdowns for competitive success.

   Eukaryotic vs Prokaryotic Ribosomes

   Eukaryotic 80S ribosomes feature a 60S subunit with 28S, 5.8S, 5S rRNAs and ~49 proteins, plus 40S with 18S rRNA and ~33 proteins. Prokaryotic 70S have 50S (23S, 5S rRNAs, ~34 proteins) and 30S (16S rRNA, ~21 proteins). Option (A) nails 60S rRNAs; (B) approximates 60S proteins accurately.

   Why (A) and (B) Only?

   These options list verifiable eukaryotic 80S ribosome components from the large subunit, confirmed in high-resolution structures. (C) and (D) introduce prokaryotic 23S rRNA, a common exam trap.

   GATE Exam Strategy

   • Focus: Memorize 28S/5.8S/5S for 60S; avoid mixing with bacterial 23S.

   • Practice: PYQs on eukaryotic 80S ribosome components boost molecular biology scores.(A), (B) and (C) only