Online Microbiology Notes

Food Spoilage- Types of microorganisms in foods with examples

March 14, 2021 by Sanjogta Thapa Magar

What is Food Spoilage? Food spoilage is a metabolic process that causes foods to be undesirable or unacceptable for human consumption due to changes in sensory characteristics. Spoilage of food is identified by off-colors, off-odors, softening of vegetables, fruits, and slime production. Spoilage may arise from insect damage, physical damage, and indigenous enzyme activity in food or by microorganisms (bacteria, …

Chromosomal Mutation- Definition, Causes, Mechanism, Types, Examples

March 11, 2021 by Anupama Sapkota

What are Chromosomes? Chromosomes are long thread-like structures of DNA that contain part or all of the genetic material of an organism. Chromosomes exist in a complex three-dimensional structure which is essential in transcriptional regulation. Chromosomes exhibit unique compactness as the unraveled form of the chromosome would be metered in length, but the compact form can be easily placed within …

Frameshift Mutation- Definition, Causes, Mechanism, Applications, Examples

March 11, 2021 by Anupama Sapkota

Frameshift mutation definition A frameshift mutation is a type of genetic mutation resulting from the alteration of a number of nucleotides in DNA sequences that are not multiple of three. Frameshift mutation occurs as a result of a change in the reading frame of the sequence. Since the codons for gene expression occur in the form of triplets, the difference …

Silent Mutation- Definition, Causes, Mechanism, Applications, Examples

March 11, 2021 by Anupama Sapkota

What are Silent mutations? Silent mutations are mutations where the changes in the nucleotide sequence of DNA do not produce any observable effect on the organism. The change in nucleotide doesn’t produce a change in the amino acid sequence or the structure and function of the protein. Silent mutations are also termed neutral mutations as these do not cause any …

Nonsense Mutation- Definition, Causes, Mechanism, Applications, Examples

March 11, 2021 by Anupama Sapkota

Nonsense mutation definition A nonsense mutation is a type of mutation where a premature stop codon is added to a sequence which hinders the further translation of the protein-coding gene. The nonsense mutation is classified as a loss-of-function change where the mutation impairs the production of a particular protein. Nonsense mutation, like most other mutations, can have a range of …

Missense Mutation- Definition, Causes, Mechanism, Types, Examples

March 11, 2021March 11, 2021 by Anupama Sapkota

Missense mutation definition A missense mutation is a type of mutation where the alteration of a nucleotide base in a gene sequence results in the translation of different amino acids in the protein. A missense mutation is a type of nonsynonymous substitution in a DNA sequence, indicating that the mutation results in some kind of effect on the resulting sequence. …

Anabolism vs Catabolism- Definition, 13 Key Differences, Examples

March 10, 2021March 9, 2021 by Anupama Sapkota

Anabolism Definition Anabolism is a set of enzyme-catalyzed reactions that synthesize relatively complex molecules from simple structures in living systems. Anabolism is also called biosynthesis as it is involved in the formation of various compounds that are then used as cell components as well as energy. The process of anabolism requires energy; thus, it is an endergonic process, and the …

Point mutation- Definition, Causes, Mechanism, Types, Examples, Applications

March 11, 2021March 7, 2021 by Anupama Sapkota

Point mutation definition Point mutation is a type of genetic mutation where one of the base pairs in the DNA sequence is altered either by insertion or deletion. Point mutation, as the name indicates, occurs at a particular point of the DNA sequence as a result of changes in one particular base pair. Usually, point mutations arise as a result …

Mass Spectrometry (MS)- Principle, Working, Instrumentation, Steps, Applications

March 22, 2021March 4, 2021 by Sagar Aryal

Mass Spectrometry (MS) Definition Mass Spectrometry (MS) is an analytical chemistry technique that helps identify the amount and type of chemicals present in a sample by measuring the mass-to-charge ratio and abundance of gas-phase ions. In this instrumental technique, the sample is converted to rapidly moving positive ions by electron bombardment and charged particles are separated according to their masses. …

Bacillus anthracis- An Overview

February 19, 2021 by Anupama Sapkota

Bacillus anthracis definition Bacillus anthracis is the only obligate pathogenic species of Bacillus and the causative agent of anthrax, which is a common disease of livestock and occasionally occurs in humans. Anthrax is called a zoonotic disease as the disease can transfer between animals and humans via different means. It is a Gram-positive spore-forming bacterium that is commonly found in …