Pre AP Biology -GEN 3.3 Translation- MCQ Exam Style Questions -New Syllabus
Pre AP Biology -GEN 3.3 Translation- MCQ Exam Style Questions – New Syllabus 2025-2026
Pre AP Biology -GEN 3.3 Translation- MCQ Exam Style Questions – Pre AP Biology – per latest Pre AP Biology Syllabus.
▶️ Answer/Explanation
The correct option is b.
In the human genome, protein-coding genes account for only about $1\%$ to $2\%$ of the total DNA.
The remaining sequences, often historically referred to as “junk DNA,” make up the vast majority of the genome.
Current biological estimates suggest that non-coding regions constitute approximately $98\%$ to $99\%$ of our genetic material.
Therefore, removing all non-coding sequences would result in a genome shorter by roughly $90\%$ or more.
While the term “junk” is now considered a misnomer due to discovered regulatory functions, the physical reduction in size remains accurate.
This massive reduction would drastically alter the structural integrity and regulatory capacity of the cell.
▶️ Answer/Explanation
The process of RNA splicing removes non-coding regions called introns from the pre-mRNA transcript.
During this maturation, the protein-coding regions, known as exons, are joined together.
Because large segments of nucleotides are physically excised, the total length of the strand decreases.
Option (a) is incorrect as codons define the sequence but do not cause physical shrinking.
Option (b) is incorrect because promoters are part of DNA and are not transcribed into mRNA.
Option (c) is a teleological fallacy and not a biological mechanism for mRNA processing.
Therefore, the physical removal of nucleotides via splicing makes the mature mRNA shorter.
▶️ Answer/Explanation
The correct answer is c. hormone response element.
Steroid hormones are lipophilic and diffuse directly across the plasma membrane.
The hormone receptor (a) is synthesized in the cytosol and must cross into the nucleus.
RNA polymerase (b) is a protein synthesized in the cytosol that functions inside the nucleus.
The mRNA (d) is created in the nucleus but must cross the nuclear pore to be translated.
The hormone response element (c) is a specific $DNA$ sequence located within the nucleus.
Because it is part of the genome, it is “created” during $DNA$ replication inside the nucleus.
It performs its function (binding the receptor complex) entirely within the nuclear environment.
Therefore, it is the only component listed that never crosses the nuclear membrane.