In the context of cellular and molecular life sciences, which of the following best describes the role of the ribosome in a cell?
A. Ribosomes are responsible for synthesizing lipids and steroids within the cell.
B. Ribosomes are involved in the process of protein synthesis by translating mRNA into amino acid sequences.
C. Ribosomes function as the primary site for cellular respiration, generating ATP for energy.
D. Ribosomes are key in the replication of DNA, ensuring accurate duplication during cell division.

Explanation: Ribosomes are spherical organelles made up of both RNA and protein. A cell usually has many ribosomes floating around within its cytoplasm. The primary function of these ribosomes is to translate mRNA molecules into proteins by synthesizing amino acids together to create polypeptide chain. Thus, choice B is the best answer. The other answer choices showcase functions of other organelles.

Choice A is incorrect because the function mentioned in that answer choice is handled by the smooth endoplasmic reticulum. (or smooth ER,) The smooth ER is responsible for synthesizing lipids, cleansing the cell of toxins, and storing calcium.

Choice C is incorrect because ribosomes do not conduct cellular respiration. Rather, it is the mitochondria that is responsible for generating ATP through cellular respiration.

Choice D is incorrect because ribosomes play no role in DNA replication. DNA replication is instead handled by many other enzymes, such as helicase, DNA polymerase, and ligase.