CHAPTER 2 BASICS OF MOLECULAR BIOLOGY

PROTEINS SYNTHESIS

Proteins synthesis is a process that takes place in the cells of all living things: PRODUCTION OF PROTEINS. This process actually consists of two processes — transcription and translation. In eukaryotic cells, transcription takes place in the nucleus. During transcription, DNA[1] is used as a template to make a molecule of messenger RNA[2] (mRNA). The molecule of mRNA then leaves the nucleus and goes to a ribosome in the cytoplasm, where translation occurs. During translation, the genetic code in mRNA is read and used to make a protein. These two processes are summed up by the central dogma[3] of molecular biology: DNA → RNA → Protein.

TRANSCRIPTION

Transcription

Transcription is the process of making an RNA[2] copy of a Gene[4] sequence. This copy, called a messenger RNA (mRNA) molecule, leaves the cell nucleus and enters the cytoplasm, where it directs the synthesis of the protein, which it encodes.

TRANSLATION

Translation

Translation is the process of translating the sequence of a messenger RNA (mRNA) molecule to a sequence of amino acids during protein synthesis. The genetic code describes the relationship between the sequence of base pairs in a Gene[4] and the corresponding amino acid sequence that it encodes. In the cell cytoplasm, the ribosome reads the sequence of the mRNA in groups of three bases to assemble the protein.

  1. DNA : Deoxyribonucleic Acid

  2. RNA : Ribonucleic Acid

  3. Central Dogma

    The central dogma of molecular biology is an explanation of the flow of genetic information within a biological system. It is often stated as "DNA makes RNA, and RNA makes protein", although this is not its original meaning. It was first stated by Francis Crick in 1957, then published in 1958.

  4. Gene

    A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. However, many genes do not code for proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases.

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