Question

The 60S subunit of the eukaryotic ribosome contains

• A. 28S rRNA, 5S rRNA and 8S rRNA
• B. 28S rRNA, 18S rRNA and 8S rRNA
• C. 18S rRNA, 5S rRNA and 8S rRNA
• D. 28S rRNA, 18S rRNA and 5S rRNA

Hint:

The small subunit has only one rRNA molecule (18S).
The large subunit contains all other eukaryotic rRNAs (28S, 8S, and 5S).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Eukaryotic ribosome subunits are composed of specific ribosomal proteins and ribosomal RNA (rRNA) strands.
The distribution of these rRNAs is highly conserved across eukaryotic species.

Step 2: Detailed Explanation:
The intact eukaryotic 80S ribosome contains a total of four distinct rRNA strands.
The small 40S subunit contains a single 18S rRNA molecule alongside approximately 33 proteins.
The large 60S subunit contains three distinct rRNA molecules:
28S rRNA (which provides catalytic peptidyl transferase activity).
8S rRNA (which base-pairs with 28S rRNA).
5S rRNA (which is transcribed independently in the nucleoplasm).
These three rRNAs, combined with about 49 ribosomal proteins, form the functional 60S subunit.

Step 3: Final Answer:
The eukaryotic 60S subunit contains the 28S, 5S, and 8S rRNA molecules.