Question

Choose the correct statements among the following: A) Transcriptase catalyzes the polymerization in 5' $\rightarrow$ 3' direction only and the 3' $\rightarrow$ 5' strand is referred to as template. B) The chemical method of Khorana was instrumental in the synthesis of homopolymers of RNA. C) tRNA amino acid acceptor end has bases complementary to the code. D) 23s r-RNA in bacteria is a ribozyme.

• A. A, B, C
• B. B, C, D
• C. A, C, D
• D. A, B, D

Hint:

Ribozymes are RNAs that catalyze reactions; 23S rRNA is the "heart" of the ribosome!

Answer 1

The Correct Option is D

Step 1: Read the four statements.
The statements cover the direction of transcription, Khorana's RNA synthesis, the tRNA acceptor end, and a bacterial ribozyme. We judge each one.

Step 2: Check statement A.
A says the enzyme makes RNA in the 5' to 3' direction while reading the 3' to 5' template strand. This is correct, since RNA polymerase always builds in the 5' to 3' direction. A is true.

Step 3: Check statement B.
B says Khorana's chemical method helped make RNA homopolymers. This is true. His synthetic RNA chains were vital for cracking the genetic code. B is correct.

Step 4: Check statement C.
C says the tRNA amino acid acceptor end has bases complementary to the codon. This is wrong. The acceptor end (the CCA-OH end) holds the amino acid, while the anticodon loop is the part that pairs with the codon. C is false.

Step 5: Check statement D.
D says the 23S rRNA of bacteria is a ribozyme. This is true, since this rRNA helps form peptide bonds and acts as an enzyme. D is correct.

Step 6: Pick the correct set.
The correct statements are A, B and D.
\[ \boxed{\text{A, B, D}} \]