DNA mismatch repair is a mechanism of repairing DNA by the removal of mismatched nucleotides via MMR proteins. The role of mismatch repair proteins in the prokaryotic DNA helped to study the mismatch repair system in the eukaryotic DNA as well. The mismatch repair system is essential, as it maintains the genome’s stability at the time …
The electron transport system refers to the “Electron transport chain” or “ETS” (in abbreviated form) that is present in the inner mitochondrial membrane. ETS involves electron transfer through a series of protein complexes from higher (NADH+) to lower energy state (O2) by releasing protons into the cytosol. A movement of proton or H+ from a …
The bilayer cell membrane is a membranous structure, which consists of two phospholipid layers. Thus, a cell membrane also refers to a phospholipid bilayer membrane composed of many phospholipid molecules. A structure of a phospholipid molecule consists of a hydrophilic head, a phosphate molecule, a glycerol molecule and two hydrophobic fatty acid tail. The phospholipid …
Clostridium botulinum is a clinically significant bacteria, which causes a sporadic but severe disease called “Botulism”. It produces a particular type of exotoxin that affects the nervous system by inhibiting the neuromuscular junction’s activity. Therefore, the botulinum toxin behaves as a neurotoxin, which blocks the release of a neurotransmitter (acetylcholine). Acetylcholine is a chemical compound …
Botulism disease is caused by a bacterial agent, Clostridium botulinum, that produces an exotoxin. Clostridium botulinum causes bacterial food poisoning or intoxication as it releases exotoxin. Exotoxin acts as a neurotoxin, which disables the normal functioning of the nervous system. Thus, an exotoxin produced by Clostridium botulinum is called botulinum neurotoxin, which blocks the synthesis of the …
Acid-fast staining was originally pioneered by a scientist named Paul Ehrlich in the year 1882. Later, it was modified by Ziehl and Neelson in 1883. Thus, acid-fast staining is also called Ziehl Neelson staining. It is a type of differential staining method used to distinguish between the acid-fast and non-acid fast bacteria. Mycobacterium is an …
Photoreactivation repair is the DNA repair system, which corrects the damage (caused by UV-C and UV-B radiations) with the aid of photolyase enzyme under the exposure of visible light. The first evidence for the photoreactivation was given by the two scientists, namely Hausser and Von Oehmcke, in 1933. Hausser and Von Oehmcke reversed the darkened …
Excision repair is one of the types of DNA repair systems. It is an enzymatic process, which follows a cut, copy and paste mechanism. A cutting mechanism involves removing a damaged part or unusual bases by specific enzymes like glycosylases and helicases. Then, a copying mechanism uses DNA polymerase. DNAP-I uses the template DNA to …
Gynoecium, carpel or pistil primarily comprises three structures, namely stigma, style and ovary. It accounts for the flower’s female reproductive part that carries the female gametes or ovules within an ovary. Towards the gynoecium base, the pedicle or thalamus provides support to the female reproductive part and the other parts as well. An ovary is …
DNA generally exists in three common types (represented as B, A and Z forms). Besides B, A and Z forms, DNA may rarely exist as A, C and E forms. Therefore, DNA possesses six different forms that are either in a left or right-handed fashion, under appropriate physiological conditions. Inspite of the above six forms, DNA …