Question

Some library clones may not code for a full-length protein because (check all that apply):

Option 1: They are non-coding DNA regions.
Option 2: They contain introns.
Option 3: They are derived from prokaryotes.
Option 4: They lack promoter regions.

Answer 1

Library clones may not produce a full-length protein if they contain non-coding DNA regions, include introns, or lack promoter regions necessary for gene expression.

Step-by-step explanation:

Some library clones may not code for a full-length protein for several reasons. Among the options provided, the correct ones are:

• They are non-coding DNA regions: These regions do not encode proteins or stable RNA products and include areas such as introns and sequences upstream of coding sequences.
• They contain introns: Introns are sequences found in eukaryotic genes that are transcribed into mRNA but are removed during processing and thus do not encode functional proteins.
• They lack promoter regions: Without the necessary promoter regions, the gene may not be properly expressed, and thus a full-length protein may not be synthesized.

Option 3, stating that library clones derived from prokaryotes may not code for a full-length protein, is not correct because prokaryotic genes typically do not contain introns and are usually able to code for their proteins without the splicing processes required in eukaryotes.