Structure, Classification, and Functions of Carbohydrates

Introduction Living organisms require biomolecules for several biological processes like energy storage and regulation of their metabolic cycles. Among all, carbohydrates, nucleic acids, lipids, and proteins are the four major biomolecules (or macromolecules) that are mainly involved in these biological processes. The functions of carbohydrates are essential for life in all organisms, from microorganisms to […]

Active Transport: Definition, Types, and Examples

Introduction The membrane’s ability to control the transport of materials across the membrane is one of the essential life processes in organisms. The membrane determines what solutes shall enter or leave the cell, which involves complex structures functioning in the transfer of molecules across the membrane. And any mutation or malfunction in this transport mechanism […]

Site-Directed Mutagenesis: Methods and Applications

Site-directed mutagenesis is a technique conceived in the 70s used to mutate specific DNA sequences in vitro. It relies on synthetic short single-stranded DNA fragments, or oligonucleotides, that contain designated mutations to act as templates in the presence of DNA polymerase enzyme. In the late 80s, Polymerase Chain Reaction (PCR), another laboratory technique, was incorporated into site-directed mutagenesis workflow. The […]

Classification and Biological Functions of Lipids

Introduction Lipids are one of the major macromolecules present in our body, and others include nucleic acids, carbohydrates, and proteins. But unlike the other macro biomolecules, lipids are not polymers – they aren’t composed of monomers. They are hydrophobic in nature because of the predominance of hydrocarbon chains (–CH2–CH2–CH2–CH2–) in their structures.[1] Lipids have diverse […]

Factors That Affects Enzyme Activity

Enzymes are a group of proteins that catalyze non-spontaneous chemical reactions in any biological system. In an organism, enzymes function as a group of interconnected chemical reactions in a metabolic pathway, fulfilling a specific cellular task. Metabolic pathways are active under normal circumstances and alter their activities in response to internal and external stimuli. Delayed response or failure to answer […]

Types of Nucleic Acids and Their Biological Significance

Introduction and History Nucleic acids are an essential class of macromolecules present in all cells of organisms including viruses.[1] They were first discovered by Friedrich Mischer in 1869. He wanted to study the composition of leukocytes from the pus cells of discarded surgical bandages. During his study, he observed nucleic acids in the form of […]

Allosteric Enzymes: Characteristics, Models, and Examples

Introduction Allosteric enzymes are a group of biocatalysts that possess common characteristics of an enzyme but do not exhibit a typical Michaelis-Menten kinetic behavior. Instead, their kinetics follow a sigmoid curve. The key to allosteric enzyme activity lies in the reversible binding to a specific molecule on a non-catalytic site of the enzyme. The binding […]

Bacteriophage λ DNA Purification from Liquid Cultures

In the past, bacteriophage λ DNA purification was largely achieved through procedures that involved Cesium chloride gradients. However, these methods had a low recovery rate and a high chance of the presence of contaminants. Modern bacteriophage λ DNA purification methods give high yield and provide DNA free from contamination (Pickard, 2009). We can also purify […]

Bacteriophage λ DNA Purification from Plate Lysates

Introduction Genomic DNA or cDNA clones are analyzed in a simple procedure that begins with the restriction digestion of phage DNA mini preparations. The digested DNA is then assessed by agarose gel electrophoresis. For the rapid analysis, one can purify bacteriophage DNA from plate lysates as well as liquid cultures. This method explains the purification […]