Viroids are sub-viral infectious entities that infect plants. They are acellular infectious agents like the prions that lack the essential features of a virus; and which are capable of directing their own replication since they have small naked RNA as their genome. Unlike the prions which lack nucleic acids (inclusive of DNA and RNA), viroids […]
Prions are sub-viral infectious entities that consist mainly of proteins. They are unique infectious particles that lack nucleic acids inclusive of DNA and RNA. Prions are infectious proteins that generally lack DNA and RNA; and they cause series of diseases in man and animals. They differ from the normal virion in so many ways. Prions
Fredrick Griffith showed in 1928 that deoxyribonucleic acid (DNA) is the genetic material of the cell. His work was unique because it was the first evidence that showed that DNA is the genetic material of the cell. Other scientists that also carried out experiments to establish that DNA is the genetic material include Oswald Avery,
Bacterial Transformation (The Transforming Principle) Read More »
Biotechnology, Molecular Microbiology
An understanding of the nucleic acid molecules which include deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) important for us to understand the molecular and/or genetic basis of life. Nucleic acid molecules are found in all living organisms as the carriers of genetic materials from parent organisms to their offspring’s. With the exception of viruses (which
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Biotechnology, Molecular Microbiology
Proteins are a group of polypeptides that form a molecule of specific biological function; and they comprises mainly of amino acid sequences that are held together by a special type of covalent bonds known as peptide bonds. They are macromolecules that consist of long chains of amino acids held together in structural forms known as
PROTEIN STRUCTURE – types and function Read More »
Biotechnology, Molecular Microbiology
Purines are heterocyclic aromatic organic compound that consist of a pyrimidine ring fused to an imidazole ring. Purines are the larger of the two types of bases found in DNA. Adenine (A) and guanine (G) are purines. Adenine is always paired with thymine, and guanine is always paired with cytosine. Purines unlike pyrimidines (which have
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Biotechnology, Molecular Microbiology
Nucleotides are nucleosides with one or more phosphate groups covalently attached to the 3′ or 5′-hydroxyl group(s) (OH–) of a pentose sugar. A nucleoside is one of the four (4) DNA bases (i.e. adenine, guanine, cytosine and thymine) covalently attached to the carbon-one (C1) position of a sugar molecule such as the pentose sugar. Deoxyribose
Microbial cells employ a variety of mechanisms to uptake nutrients (including macromolecules, inorganic ions, water and other small molecules) from their natural environment or from artificially prepared cultured media which are precisely designed to provide all the essential nutritional requirements and growth factors necessary for microbial or bacterial growth. The cell wall or outer covering
Mechanisms for uptake of nutrients by microorganisms – diffusion & active transport Read More »
Microbial Physiology & Metabolism, General Microbiology
Living organisms vary in terms of their mode of nutrition i.e. how they feed or obtain their food. Some organisms are known as autotrophs because they can manufacture their own food; and examples include green plants and green algae. Autotrophs use carbondioxide (CO2) as their sole source of carbon for growth. Plants contain chlorophyll which
NUTRITIONAL GROUPS OF MICROORGANISMS Read More »
General Microbiology, Microbial Physiology & Metabolism
Bacterial Nutritionis importantfor the optimum growth of the organism because it is the only means by which the organism can acquire all necessary materials required for its cellular biosynthetic activities as well as for the generation of energy (i.e. adenosine triphosphate, ATP). Nutrients are substances required for energy production and other biosynthetic activity necessary for
Microbial (Bacterial) Nutrition Read More »
Microbial Physiology & Metabolism, General Microbiology