Bbbcvbvc

Molecular

Dr Kourash

DNA

What is molecular biology?

Molecular biology is a branch of science concerning biological activity at the molecular level.

The field of molecular biology overlaps with biology and chemistry and in particular, genetics and biochemistry. A key area of molecular biology concerns understanding how various cellular systems interact in terms of the way DNA, RNA and protein synthesis function. Genetics is concerned with the effects of genes on living organisms, which are often examined through “knock-out” studies, where animal models are designed so that they lack one or more genes compared to a “wild type” or regular phenotype.

Molecular biology looks at the molecular mechanisms behind processes such as replication, transcription, translation and cell function. One way to describe the basis of molecular biology is to say it concerns understanding how genes are transcribed into RNA and how RNA is then translated into protein. However, this simplified picture is currently be reconsidered and revised due to new discoveries concerning the roles of RNA.

The specific techniques used in molecular biology are native to the field but may also be combined with methods and concepts concerning genetics and biochemistry, so there is no big distinction made between these disciplines.

What Are the Initial Steps in Accessing Genetic Information?

Transcription is the first step in decoding a cell's genetic information. During transcription, enzymes called RNA polymerases build RNA molecules that are complementary to a portion of one strand of the DNA double helix.

Three general classes of RNA molecules are involved in expressing the genes encoded within a cell's DNA. Messenger RNA (mRNA) molecules carry the coding sequences for protein synthesis and are called transcripts; ribosomal RNA (rRNA) molecules form the core of a cell's ribosomes (the structures in which protein synthesis takes place); and transfer RNA (tRNA) molecules carry amino acids to the...