Sourav Pan is the founder and sole author of Biology Notes Online. He holds a Bachelor of Science (B.Sc.) degree and an M.Sc. in Microbiology from the University of Calcutta. He creates educational resources covering microbiology, immunology, biotechnology, genetics, cell biology, botany, zoology, and other life-science subjects.
His goal is to make complex biological concepts easier to understand through well-structured, student-friendly articles based on academic textbooks, peer-reviewed research, and authoritative scientific sources. In addition to writing new content, he regularly reviews and updates articles to improve their accuracy, clarity, and educational value.
Pipette is a precision laboratory instrument used for measuring, transferring and dispensing small amount of liquid. The word pipette is taken from French word, which means little pipe. It is commonly used in chemistry, biology and medical research work. Pipette is used for measuring liquid in millilitre or microlitre range. It helps to take accurate … Read more
Inoculating loops and needles are hand held laboratory instruments used in microbiology. These are used to pick and transfer small amount of microorganisms from one culture medium to another. The small amount of microorganism which is transferred is called inoculum. These instruments are also called smear loops, inoculation wands or microstreakers. They have a handle, … Read more
Colorimeter is a light sensitive analytical instrument used to measure absorbance and transmittance of light. It measures selected wavelength of light when it passes through a coloured solution. It is mainly used for finding the concentration of coloured solution. The working of colorimeter is based on Beer-Lambert law. According to this law, the amount of … Read more
Hot air oven is a specialized laboratory and industrial equipment used for dry heat sterilization, drying and thermal processing. It is an electrical device having thermostatically controlled insulated chamber, where hot air is circulated. The normal temperature range is about 50°C to 300°C. It is mainly used for sterilization of materials which are heat-resistant but … Read more
Gel electrophoresis system is a laboratory setup used for separation of charged biological molecules. It is used for DNA, RNA and proteins. It contains a gel box, gel matrix, running buffer and power supply. The gel matrix may be agarose or polyacrylamide. The buffer conducts electric current and keeps the molecules moving properly. When electric … Read more
Alcohol burner is a small laboratory heating instrument used for gentle heating and sterilization. It is also called spirit lamp. It is made up of glass, brass, aluminium or stainless steel. It has a fuel reservoir and a cap with cotton wick. Some burners may also have wickless copper tube. The fuel used in alcohol … Read more
Bunsen burner is a laboratory instrument used for heating, sterilization and burning of substances. It gives an open flame. The flame can be controlled by changing the air supply. It uses gas like natural gas, propane or butane. The gas enters into the burner tube and mixes with air. Then the mixture burns at the … Read more
Colony counter is an instrument used in microbiology laboratory for counting microbial colonies grown on agar plate. It is used for bacteria, yeast, fungi and other microorganisms. It counts the number of Colony Forming Units (CFU) present on the plate. Each colony is considered as formed from one viable microbial cell or group of cells. … Read more
Two pan analytical balance is a classical weighing instrument used for measuring mass of an object. It is also called equal arm analytical balance because both arms of the beam are equal in length. It works on the principle of first class lever. The beam is supported at the centre on a sharp knife-edge. This … Read more
Single pan mechanical balance is a precise weighing instrument used for measuring mass of a sample. It is also called unequal arm mechanical balance because the two arms of the beam are not equal in length. It works on the law of moments or lever principle. The balance has a horizontal beam which rests on … Read more