Question

Shura listed the steps for protein production in cells.

1. A strand of RNA is made.
2. RNA leaves the nucleus.
3. RNA moves to the ribosome.
4. A protein is made.

Which step is missing?
A. DNA unzips after step 1.
B. DNA unzips before step 1.
C. DNA is replicated after step 3.
D. DNA is replicated before step 3.

Answer 1

B. DNA unzips before step 1.

Step-by-step explanation:

This question is describing the process of gene expression, which is made up of two major stages namely; transcription and translation. Transcription is the process by which mRNA is synthesized from a DNA template while translation is the process where protein (amino acid sequence) is produced using the mRNA transcript.

This stages of gene expression has been summarized in the steps listed by Shura. However, prior to the formation of an mRNA molecule in step 1, the double stranded DNA has to unwind i.e. separate into single strands as initiated by the enzyme RNA polymerase. Therefore, the list should read as follows:

- DNA unzips

- A strand of RNA is made.

- RNA leaves the nucleus.

- RNA moves to the ribosome.

- A protein is made.