RibosomesA JOURNEY INTO A CELL.

BY: AARON LOGAN MANCUSO

What is a Ribosome?

Ribosomes are cell organelles that consist of RNA and proteins.

They make proteins by joining amino acids together.

Depending on the protein production level of a particular cell, ribosomes may number in the millions.

The purpose of the ribosome is to translate messenger RNA (mRNA) into proteins with the aid of tRNA.

Distinguishing Characteristics:

Ribosomes are typically composed of two subunits:

a. A large subunit.

b. A small subunit.

Ribosomal subunits are synthesized by the nucleolus.

These two subunits join together when the ribosome attaches to messenger RNA (mRNA) during protein synthesis.

Ribosomes along with another RNA molecule, transfer RNA (tRNA), help to translate the protein-coding genes in mRNA into proteins.

Location in the Cell: There are two places that ribosomes usually exist

in the cell:

a. Suspended in the cytosol.

b. Bound to the endoplasmic reticulum.

These ribosomes are called free ribosomes and bound ribosomes respectively.

Free ribosomes usually make proteins that will function in the cytosol.

While bound ribosomes usually make proteins that are exported from the cell or included in the cell's membranes.

Free ribosomes and bound ribosomes are interchangeable and the cell can change their numbers according to metabolic needs.

Protein Assembly: Protein synthesis occurs by the processes of transcription

and translation.

In transcription, the genetic code contained within DNA is transcribed into an RNA version of the code known as messenger RNA (mRNA).

Ribosomal RNA helps to link amino acids together to produce the polypeptide chain.

The polypeptide chain undergoes several modifications before becoming a fully functioning protein.

Proteins are very important biological polymers in our cells as they are involved in virtually all cell functions.

Ribosomes and the disease’s associated with them:

Anything that disrupts the function of ribosomes (their ability to make proteins) has potentially serious and sometimes fatal consequences

Alzheimer's disease - A type of dementia that causes problems with memory, thinking and behavior.

Diamond-Blackfan anaemia - A condition where individuals have a very low red blood cell count.

Cartilage Hair Hypoplasia - A hereditary disease that causes thin light-colored hair, short limbs and a short stature.