Final answer:
rRNA is produced in the nucleolus and plays a crucial role in protein synthesis on the ribosomes, which are often found on the rough endoplasmic reticulum. rRNA works with mRNA and tRNA during translation to produce proteins.
Step-by-step explanation:
The substance that is produced in the nucleolus, attaches to the endoplasmic reticulum on the inside, and manufactures new proteins is ribosomal RNA, more commonly known as rRNA. The nucleolus is the organelle where rRNA is synthesized, which is essential for the assembly of ribosomes. Ribosomes are attached to the surface of the rough endoplasmic reticulum (ER) and are responsible for protein synthesis. As part of the ribosome, rRNA helps to align the mRNA (messenger RNA) and tRNA (transfer RNA) during protein synthesis, ensuring that amino acids are added in the correct order to form the protein.
To answer the initial question: The RNA components of ribosomes are synthesized in the d. nucleolus. This rRNA, along with proteins, composes the ribosome's structure. The ribosomes, many of which are associated with the rough ER, carry out the synthesis of proteins. When mRNA is ready to be translated, the ribosome subunits attach to it, providing the necessary platform for protein assembly.