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

Where are lysosomes synthesized?

1. Smooth endoplasmic reticulum

2. Rough endoplasmic reticulum

3. Golgi apparatus

4. Nucleus

The correct answer is: Rough endoplasmic reticulum

Lysosomes are synthesized primarily in the rough endoplasmic reticulum (RER). The rough endoplasmic reticulum is studded with ribosomes, which are the sites of protein synthesis. Ribosomes translate mRNA into polypeptide chains, which are then processed within the RER. During this process, enzymes and other proteins that are necessary for lysosome function are produced. Once the proteins are synthesized in the RER, they are transported to the Golgi apparatus for further processing, modification, and packaging. The Golgi then sorts and targets the enzymes to lysosomes. While the Golgi apparatus plays a crucial role in the final stages of lysosome formation and function, the initial synthesis of lysosomal proteins occurs in the rough endoplasmic reticulum. The other options refer to different organelles involved in various cellular processes but are not the primary sites for the synthesis of lysosomal components. The smooth endoplasmic reticulum is primarily involved in lipid synthesis and detoxification, the Golgi apparatus is responsible for modifying and shipping proteins (including those for lysosomes), and the nucleus houses the genetic material but does not directly synthesize lysosomal enzymes.