Microbiology Demystified by Tom Betsy & James Edward Keogh

Author:Tom Betsy & James Edward Keogh [Betsy, Tom & Keogh, James Edward]
Language: eng
Format: epub
Tags: Life Sciences, Science, Medical, Biology, General, Medical Microbiology, Bacteriology, Microbiology
ISBN: 9780071446501
Google: yZva9QFY_cQC
Publisher: McGraw-Hill Prof Med/Tech
Published: 2005-05-25T06:00:00+00:00

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CHAPTER 7

Microbial Genetics

Once the transcription process is completed, information of the mRNA is turned into protein in the translation process. The translation process is one in which genetic information encoded in mRNA is translated into a specific sequence of amino acids that produce proteins.

Appropriate amino acids are brought to the translation site in the ribosomes and are assembled into a growing chain. It is here that tRNA recognizes specific codons. Each tRNA molecule has an anticodon, which is a sequence of three bases that is complementary to the bases on the codon. These bases are then paired, and amino acids are brought to the chain.

This process continues until a polypeptide is produced. The polypeptide is removed from the ribosome for further processing. The polypeptide may be stored in the Golgi body of a eukaryotic organism. The mRNA molecule degenerates and the nucleotides are returned to the nucleus. The tRNA molecule is returned to the cytoplasm and combines with new molecules of amino acids.

GENOTYPE AND PHENOTYPE: REALIZING

YOUR POTENTIAL

The genetic makeup of an organism is called a genotype and represents that organism’s potential properties. Some properties may not have developed. Those that do develop are called an organism’s phenotype. The phenotype represents expressed properties, such as blue eyes and curly hair.

A genotype is the organism’s DNA (a collection of genes). The phenotype is a collection of proteins. The majority of the cell’s properties comes from the structures and functional properties of these proteins.

Controlling Genes: You’re Under My Spell

The process of making proteins (remember, polypeptides become proteins either after they are combined with other polypeptides or when they become biologically functional) begins with the copying of the genetic information found in DNA, into a complimentary strand of RNA. This copying is called transcription.

Messenger RNA (mRNA) will carry the coded information or instructions for assembling the polypeptides from DNA to the ribosomes of the cell’s endoplasmic reticulum where the polypeptides will be made.

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