AP BIOLOGY

Detailed explanation-1: -The endoplasmic reticulum can either be smooth or rough, and in general its function is to produce proteins for the rest of the cell to function. The rough endoplasmic reticulum has on it ribosomes, which are small, round organelles whose function it is to make those proteins.

Detailed explanation-2: -Ribosomes. Ribosomes are the protein factories of the cell. Composed of two subunits, they can be found floating freely in the cell’s cytoplasm or embedded within the endoplasmic reticulum.

Detailed explanation-3: -To build proteins, the two ribosomal subunits, small and large, assemble together to form the complete ribosome. It has binding sites for mRNA and transfer RNA (tRNA) molecules. The large subunit sits on top of the small subunit, with the mRNA template sandwiched in between the two.

Detailed explanation-4: -The nucleolus: an organelle formed by the act of building a ribosome.

Detailed explanation-5: -All living cells contain ribosomes, tiny organelles composed of approximately 60 percent ribosomal RNA (rRNA) and 40 percent protein. However, though they are generally described as organelles, it is important to note that ribosomes are not bound by a membrane and are much smaller than other organelles.