Question

Describe the types of RNA and how they function. (page 493 )

Short answer

The three primary types of RNA are mRNA (messenger RNA), rRNA (ribosomal RNA), and tRNA (transfer RNA), each with specific functions in protein synthesis. mRNA carries the genetic information from DNA in the nucleus to the ribosome in the cytoplasm, acting as a blueprint for protein construction. rRNA is a component of ribosomes, providing a scaffold and catalytic function in protein synthesis. tRNA serves as a link between the genetic code (carried by mRNA) and amino acids, ensuring correct alignment during protein formation.

Step-by-step solution

Understanding the role of RNA

To understand the types of RNA and their functions, it's essential to know the role of RNA in general. RNA, or ribonucleic acid, is a molecule that plays a critical role in the synthesis of proteins within cells. RNA is made up of nucleotides, which are the building blocks of nucleic acids. In the process of protein synthesis, RNA transcribes the genetic information from DNA found in the nucleus and then translates that information into proteins at the ribosome.

Messenger RNA (mRNA)

mRNA serves as a blueprint for the construction of proteins. The DNA sequence of a gene is transcribed into mRNA in a process called transcription, where the mRNA is a complementary copy of the DNA template. Once created, the mRNA leaves the cell nucleus and moves to the cytoplasm, where it binds to a ribosome.

Ribosomal RNA (rRNA)

rRNA is a component of the ribosomes, which are the cellular structures where proteins are synthesized. The rRNA provides a scaffold for the ribosome and creates a site where the amino acids can be brought together to form a peptide bond and create the protein chain. Moreover, rRNA has a catalytic function, meaning it can help speed up the process of protein synthesis.

Transfer RNA (tRNA)

tRNA molecules work as the link between the genetic code (carried by the mRNA) and the amino acids that make up proteins. Each tRNA molecule contains an anticodon sequence that is complementary to the codon on the mRNA. Meanwhile, tRNAs also carry a specific amino acid at their other end. The tRNA molecules bind to the mRNA at the ribosome, pairing their anticodons with the mRNA's codons. This allows the amino acids on the tRNA to align in the correct order to form the protein. To summarize: 1. mRNA carries the genetic information from the DNA in the nucleus to the ribosome in the cytoplasm. 2. rRNA is part of the ribosome and contributes to its structure and function. 3. tRNA carries specific amino acids to the ribosome, ensuring that the amino acids are correctly added to the growing protein chain.