Ribosomes are small but important parts of our cells. They help make proteins, which are essential for all life. The way ribosomes are built is closely connected to how they work, especially in turning messenger RNA (mRNA) into proteins.

Structure of Ribosomes

1. What They're Made Of:

   • Ribosomal RNA (rRNA): This makes up about 60% of a ribosome. It helps keep the ribosome strong and plays a key role in its activity.
   • Proteins: About 40% of a ribosome is made up of proteins. These proteins help keep the ribosome’s shape and stability.

2. Parts of Ribosomes:

   • Large Subunit: In simple cells (prokaryotes), it’s called 50S. In more complex cells (eukaryotes), it’s called 60S. This part helps join amino acids together to form proteins.
   • Small Subunit: In prokaryotes, it’s 30S; in eukaryotes, it’s 40S. This part reads the mRNA and ensures that tRNA (which carries amino acids) is in the right position.

3. Size: Ribosomes are usually about 20-30 nanometers wide. For instance, eukaryotic ribosomes (80S) are larger than prokaryotic ribosomes (70S). The "S" stands for Svedberg unit, which tells us about how they settle in a solution.

Function of Ribosomes

1. Making Proteins: Ribosomes are often called the "workbench" for making proteins. They take the genetic instructions from mRNA and turn them into amino acids, which can help produce many proteins every minute.

2. How Translation Works:

   • Starting (Initiation): The small subunit grabs onto the mRNA.
   • Building (Elongation): tRNA brings in amino acids, and the large subunit links them together to form a chain.
   • Finishing (Termination): This process continues until the ribosome reaches a stop signal, releasing the new protein chain.

3. Speed: A single ribosome can assemble a chain of up to 1000 amino acids in just a few minutes. In eukaryotic cells, ribosomes can float freely in the cell juice (cytoplasm) or attach to the endoplasmic reticulum, helping produce proteins for the cell's outer membrane or for release outside the cell.

Conclusion

Understanding the connection between the structure and function of ribosomes is crucial for how our cells operate. The way rRNA and proteins are arranged in ribosomes allows them to make proteins accurately and efficiently. This process is key for many aspects of life at the molecular level, showing just how important ribosomes are for maintaining life.