Question

The ___ consists of two subunits that assemble around messenger RNA.

Short answer

The ribosome consists of two subunits that assemble around mRNA.

Step-by-step solution

Understanding the Context

The exercise asks for a biological structure involved in protein synthesis. This structure is part of the cellular machinery and interacts with messenger RNA during this process.

Identifying the Key Components

In the context of protein synthesis, the key components are the mRNA, ribosomal subunits, and tRNAs. The question specifically mentions components that 'assemble around messenger RNA.'

Recognizing the Main Structure

The structure that consists of two subunits and assembles around the messenger RNA is the ribosome. A ribosome has a large subunit and a small subunit, which join together to translate mRNA into a protein sequence.

Key concepts

Protein Synthesis

Protein synthesis is an essential process in cells where proteins are generated based on the instructions provided by the genetic code. It happens in two main stages: transcription and translation. Transcription occurs in the nucleus and involves copying a segment of DNA into mRNA. Translation occurs in the cytoplasm, where ribosomes read the mRNA sequence to produce a specific protein. The ribosome plays a pivotal role in this process as it synthesizes proteins by translating the mRNA sequences into amino acid chains.

• Initiation: Ribosomal subunits attach to the mRNA molecule to begin the process.
• Elongation: Transfer RNA (tRNA) brings the appropriate amino acids to the ribosome to be added to the growing protein chain.
• Termination: The process stops when a stop codon on the mRNA is reached and the newly synthesized protein is released.

Messenger RNA (mRNA)

Messenger RNA, often abbreviated as mRNA, is a vital type of RNA that serves as a template for protein synthesis. It carries the genetic information transcribed from DNA, detailing the specific sequence of amino acids needed to build a protein. mRNA ensures that the instructions encoded in the DNA are delivered to the ribosome, the site of protein production.

• Structure: mRNA is a single-stranded molecule composed of nucleotides arranged in a sequence that corresponds to the gene being expressed.
• Function: It acts as a messenger that conveys genetic information from the nucleus to the ribosome in the cytoplasm.
• Duration: mRNA molecules are temporary and will degrade after their job of guiding protein synthesis is complete, allowing only necessary proteins to be synthesized.

Ribosomal Subunits

Ribosomal subunits are crucial components of ribosomes, the cellular machines that perform protein synthesis. A ribosome is composed of two distinct subunits, known as the large subunit and the small subunit. These subunits cooperate to build proteins as they move along the mRNA strand.

• Small Subunit: The small subunit binds to the mRNA strand and is responsible for reading the genetic information.
• Large Subunit: The large subunit's main function is to catalyze the formation of peptide bonds between amino acids, creating a growing polypeptide chain.
• Assembly: These subunits join around the mRNA at the beginning of protein synthesis, working together as the mRNA is translated into a protein.