1. Ribosomes A JOURNEY INTO A CELL. BY: AARON LOGAN MANCUSO

2. 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.

4. 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.

5. 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.

6. 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.

8. 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.