NYSTCE 160 – Biology Practice Exam

The choice highlighting mitochondria and chloroplasts is correct because both of these organelles have their own distinct DNA, which is separate from the nuclear DNA found in the nucleus of the cell. This characteristic is referred to as "endosymbiotic theory," which suggests that mitochondria and chloroplasts are descendants of ancient prokaryotic cells that were engulfed by ancestral eukaryotic cells.

Both organelles replicate independently of the cell's nuclear DNA during the cell cycle, allowing them to reproduce and contribute to their respective roles in energy production and photosynthesis. Mitochondria are crucial for cellular respiration, while chloroplasts are essential for photosynthesis in plants. This self-replicating DNA enables these organelles to produce the proteins and other components necessary for their functions.

In contrast, the other choices consist of organelles that do not have this capability. For instance, the nucleus houses the cell's primary DNA, but it does not independently replicate outside of the cell cycle. Organelles like ribosomes, the endoplasmic reticulum, lysosomes, and peroxisomes are involved in processes such as protein synthesis, lipid synthesis, and detoxification, but they lack their own DNA and rely solely on the genetic