Urea synthesis takes place in
Mitochondria and endoplasmic reticulum
Mitochondria and vacuole
Lysosomes and endoplasmic reticulum
Mitochondria and cytosol
Urea synthesis is a process known as the urea cycle that occurs in the mitochondria and cytosol of cells. The initial steps of the urea cycle take place in the mitochondria, where ammonia and carbon dioxide combine to form carbamoyl phosphate. The subsequent steps occurs in the cytosol, where carbamoyl phosphate is converted into urea through a series of enzymatic reactions. Therefore, option 4 is the correct answer.