An organelle that causes the cytoplasm to show increased basophilia is the

• A. Golgi apparatus
• B. RER
• C. Lysosome
• D. Mitochondrion

Answer: (B)

Basophilia of the cytoplasm occurs when RNA-rich ribosomes are abundant, highlighting active protein synthesis. The rough endoplasmic reticulum has ribosomes studding its surface, so cells with lots of protein production show a distinctly basophilic (blue-staining) cytoplasm. This makes the rough ER the organelle most responsible for increased basophilia. The Golgi apparatus isn’t laden with ribosomes and is less basophilic because its role is processing and packaging proteins. Lysosomes contain enzymes and their contents don’t create the same basophilic effect, and mitochondria, while essential for energy production, don’t drive cytoplasmic basophilia to the same extent as ribosome-rich rough ER.