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.
What is a Glucose Tolerance Test? Glucose Tolerance Test (GTT) is a medical test which is used to measure how effectively the body processes the glucose (sugar) from blood into the tissues. It is most commonly performed as Oral Glucose Tolerance Test (OGTT). It is mainly used for diagnosis of metabolic conditions like prediabetes type … Read more
What is Cell Cycle? Cell cycle is the ordered sequence of events by which a cell grows and divides to form two genetically identical daughter cells. It is the process that ensures continuity of life by producing new cells from pre existing cells. The cell cycle is a carefully regulated process and it occurs in … Read more
What is Checkpoint? A checkpoint is a control point in cell cycle. It is a internal surveillance mechanism present in eukaryotic cell. It ensures that cell division occurs in proper manner. It act like a quality control step where progression is checked before moving to next phase. It is the process where cell checks cell … Read more
Membrane filtration method is a laboratory method which is used for estimation of microbial load (bioburden) in liquid sample like drinking water environmental water and pharmaceutical solution. It is a quantitative method and the bacteria are concentrated on a membrane filter and then counted as colony forming unit (CFU). Principle of this method is based … Read more
What is Heat and Acetic Acid Test? Heat and acetic acid test (heat coagulation test) is a simple qualitative and semi quantitative test which is used for detection of excess protein in urine sample. Mainly albumin is detected but globulin may be present also. It is done as a screening test for proteinuria. Principle of … Read more
Sulfosalicylic acid (SSA) test is a simple screening test which is used to detect excessive proteins in urine. It is a rapid and low cost method and it is mainly used for checking proteinuria which indicates kidney impairment. The test is done on clear urine sample after centrifugation so that turbidity is observed clearly. It … Read more
What is Pauly’s Test? Pauly’s test is a biochemical colour test which is used for detection of tyrosine and histidine amino acid in proteins. It is a specific colourimetric assay. It was given by Hermann Pauly (German chemist) in 1904. It is based on azo-coupling reaction. In this process sulfanilic acid is diazotized in cold … Read more
PYR test (Pyrrolidonyl Arylamidase test) is a rapid colorimetric biochemical test used in clinical microbiology. It is done for detection of enzyme pyrrolidonyl arylamidase (pyrrolidonyl aminopeptidase) in bacteria. In this test the bacteria is exposed to a synthetic substrate L-pyrrolidonyl-β-naphthylamide. If the enzyme is present the substrate is hydrolyzed and β-naphthylamine is released which is … Read more
Urease test is a biochemical assay used in microbiology to detect whether microorganism produces urease enzyme or not. It is the process in which urea is broken down into ammonia and carbon dioxide by urease enzyme. When urease producing organism is inoculated in urease broth or agar the ammonia is rapidly accumulated and pH is … Read more
Nitrite Reduction Test is a biochemical test, which is used to determine that bacteria can reduce nitrite (NO2−) into other nitrogenous compounds. The nitrite is further reduced to nitric oxide (NO), nitrous oxide (N2O), nitrogen gas (N2) or ammonia (NH3). This test mainly indicates the ability of organism to remove nitrite from medium. In this … Read more