2018 · Q6
Which one of the following statements about proteins in mammalian cells is correct?
general-sciencebiology-human-body
- AProteins in mammalian cells are synthesized in cell membrane.
- BProteins in mammalian cells are not synthesized in cell membrane but directly absorbed from food.
- CProteins in mammalian cells are synthesized in rough endoplasmic reticulum.
- DProteins in mammalian cells are synthesized in Golgi apparatus.
Explanation
In mammalian cells proteins are synthesized by ribosomes, and the ribosomes studding the endoplasmic reticulum give it its 'rough' appearance — the rough ER is the site of protein synthesis (for secretory and membrane proteins). The cell membrane is not a protein factory, and intact proteins are not directly absorbed from food. The Golgi apparatus modifies, sorts and packages proteins but does not synthesize them. Hence proteins are synthesized in the rough endoplasmic reticulum.