Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

What cellular structure is responsible for protein assembly based on genetic instructions?

1. Mitochondria

2. Nucleus

3. Ribosomes

4. Endoplasmic Reticulum

The correct answer is: Ribosomes

Ribosomes are the cellular structures primarily responsible for protein assembly according to genetic instructions. They function as the site where messenger RNA (mRNA), which carries information from DNA, is translated into proteins. Ribosomes read the sequence of mRNA and facilitate the binding of transfer RNA (tRNA) that carries the corresponding amino acids. This process, known as translation, allows the ribosomes to string together amino acids in the correct order, ultimately forming polypeptides that fold into functional proteins. Other structures within the cell, like the mitochondria, nucleus, and endoplasmic reticulum, play different roles. The mitochondria are mainly involved in energy production, while the nucleus houses the genetic material and is responsible for the transcription of DNA to mRNA. The endoplasmic reticulum is involved in the processing and transport of proteins after they have been initially assembled by the ribosomes. Thus, the ribosome's unique function of translating genetic information into protein structure clearly identifies it as the correct answer.