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Last updated date: 30th Nov 2023
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MVSAT Dec 2023

Ribosomes are made up of RNA and
A. Sugar
B. Protein
D. Cholesterol

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Hint: Ribosomes are also called ribonucleoprotein and it has important roles in various processes undertaken inside the cell.

Complete Answer:
- Ribosomes were discovered in 1955, by George E. Palade. Ribosomes are particles present in large numbers in all living cells. They are the site of protein synthesis.
- They occur both as free particles, in eukaryotes and prokaryotes, and as particles attached to the membranes of the endoplasmic reticulum in eukaryotic cells. The free ribosomes move anywhere in the cytosol, except in the cell nucleus and other organelles. Bound ribosomes generally produce proteins, use within the plasma membrane, or are expelled from the cell by exocytosis.
- Each ribosome consists of two subunits, a larger one and a smaller one. The subunits are mentioned as their sedimentation rate, which is measured in Svedberg units (S), in a centrifugal field. In eukaryotes, the small and large subunits are termed as the 40S and 60S, while prokaryotes contain a small 30S subunit and a large 50S subunit.
- Ribosomes are the sites where information carried in the genetic code is converted into protein molecules. The messenger RNA (mRNA) decides the order of transfer RNA (tRNA) molecules that are bound to the codons (nucleotide triplet).
- The order of tRNA molecules determines the amino acid sequence of a protein. The newly formed proteins, then, detach themselves from the ribosomal site and migrate to different parts of the cell for other use.
- The ribosomes are made up of proteins and RNA (rRNA). Usually, three to four rRNA molecules and about forty to eighty different ribosomal proteins are present in the ribosomes. Proteins perform many cellular functions like repairing damage or directing chemical processes.

Hence the correct option is B, ‘Protein’.

Note: Ribosomes carry out one of the major processes in the cell, known as, translation. Translation is the process by which a protein is synthesized from the information contained in a molecule of messenger RNA (mRNA)