Sourav Pan

Academic Writer, Microbiology Specialist | M.Sc. Microbiology, Calcutta University, Founder of Biologynotesonline.com

Sourav is the founder and sole author of Biology Notes Online. He holds a Master’s degree in Microbiology from Calcutta University and has over 5 years of experience in academic writing, life science content creation. His content reflects hands-on lab expertise, deep subject knowledge, and a strong passion for simplifying biology for students. Whether it’s genetics, microscopy, or metabolic pathways — Sourav explains it in a way that’s accurate, exam-focused, and easy to remember. He regularly updates and fact-checks all the material published on this site, ensuring students get trustworthy and updated biology notes with references to real scientific sources.

Protein Purification Methods

• Published on March 30, 2024 • 16 min readby Sourav Pan

What is Protein Purification? Protein Purification Methods Creating a Crude Protein Extract – Extraction Precipitation and Differential Solubilisation – Concentration of crude extract Ammonium sulfate precipitation Fractional precipitation with acetone Ultracentrifugation Sucrose gradient centrifugation Chromatographic Methods Different chromatographic methods 1. Size Exclusion Chromatography 2. Ion Exchange Chromatography 3. Affinity Chromatography 4. Metal Binding 5. Immunoaffinity … Read more

Thermodynamics – Definition, Types, 1st, 2nd, 3rd Law

• Last Updated April 2, 2024 • 0 revisions • 49 min readby Sourav Pan

The chemical energy stored in molecules can be released as heat in chemical reactions that occur when the fuel methane, coal or cooking gas burns in the air. Chemical energy could also be utilized to carry out mechanical work when fuel is burned in an engine or to generate electric energy via an electrolytic cell … Read more

Pentose Phosphate Pathway – Definition, Steps, Regulation, Importance

• Last Updated April 2, 2024 • 0 revisions • 24 min readby Sourav Pan

What is Pentose Phosphate Pathway? Pentose Phosphate Pathway Definition The Pentose Phosphate Pathway (PPP) is a metabolic pathway parallel to glycolysis that produces NADPH, pentoses (5-carbon sugars), and ribose 5-phosphate, a precursor for nucleotide synthesis. It plays a crucial role in both cellular biosynthesis and the defense against oxidative stress. Location of Pentose Phosphate Pathway … Read more

Entner–Doudoroff pathway – definition, Steps.

• Published on March 30, 2024 • 3 min readby Sourav Pan

Entner–Doudoroff pathway is an alternative pathway of Glycolysis. This pathway is found in Gram-negative bacteria, certain Gram-positive bacteria, and archaea. Entner–Doudoroff pathway Definition Entner–Doudoroff pathway containing Organisms Some example of bacteria those contain Entner–Doudoroff pathway are Pseudomonas, Azotobacter, Rhizobium, Agrobacterium, Escherichia coli, Enterococcus faecalis, Xanthomonas campestris, Zymomonas mobilis, Enterococcus faecalis. This pathway also found in … Read more

The Glyoxylate Cycle – Definition, Steps, Functions.

• Published on March 30, 2024 • 3 min readby Sourav Pan

Glyoxylate cycle Definition Glyoxylate cycle Steps Glyoxylate cycle functions The conversation of dicarboxylic and tricarboxylic acids in germinating seeds occurs in three compartments such as mitochondria, glyoxysomes, and cytosol. During the conversation, the oxaloacetate from the TCA cycle (mitochondria) enters into the glyoxysomes in the form of aspartate. After that, the aspartate converted into oxaloacetate … Read more

Mitochondrial Shuttles and Transporter Proteins.

• Published on March 30, 2024 • 3 min readby Sourav Pan

Mitochondrial transporter The mitochondria contain different types of transporter proteins within the intermembrane. These transporters transfers ADP, Pi, and H atom(Substrate) from Inter membrane space to matrix and ATP (Product) from matrix to inner membrane space. There are presently three transporter protein in the inner mitochondrial membrane such as; Adenine Nucleotide Translocase It is an … Read more

Post-glycolysis processes

• Published on March 29, 2024 • 7 min readby Sourav Pan

Post-glycolysis processes Glycolysis is a process that involves: Glucose + 2 NAD+ + 2 ADP + 2 Pi → 2 pyruvate + 2 NADH + 2 H+ + 2 ATP Glycolysis could not continue indefinitely if all NAD+ was used up and glycolysis would cease. Organisms must be capable of oxidizing NADH back into NAD+ … Read more

Regulation of Glycolysis

• Published on March 29, 2024 • 11 min readby Sourav Pan

Glycolysis is the primary stage in the process of breaking down glucose in order to obtain energy to power the cell’s metabolism. The majority of living organisms perform glycolysis as a part in their metabolic process. This process does not require oxygen, which is why it is considered anaerobic. Glycolysis happens in the cytoplasms of … Read more

Control Group – Definition, Importance, Examples

• Last Updated May 7, 2025 • 0 revisions • 10 min readby Sourav Pan

What is Control Group? Definition of Control Group A control group is a set of subjects in a scientific experiment who do not receive the treatment or intervention being studied, serving as a benchmark for comparison against the treatment group to determine the effect of the variable under investigation. Importance of Control Group The control … Read more

Cell membrane (Plasma Membrane) Structures and Functions

• Last Updated May 7, 2025 • 0 revisions • 29 min readby Sourav Pan

What is Cell membrane or Plasma Membrane? Definition of Cell membrane or Plasma Membrane The cell membrane, also known as the plasma membrane, is a semi-permeable biological barrier that surrounds and protects the cell’s interior from the external environment, regulating the passage of molecules in and out of the cell. Cell Membrane Composition The cell … Read more