Online Biology Notes for students
VIVA Alert: Basic Microbiology with mnemonics Name one cluster shaped (grape-like) cocci? Staphylococcus aureus Name one chain shaped cocci? Streptococcus spp. What is the difference between Staphylococcus aureus and Streptococcus? S. aureus is cluster shaped and Streptococcus is chain shaped. S. aureus is catalase-positive and Streptococcus is catalase negative. Name any five …
Biofertilizer- Types and Uses Biofertilizer is a substance which contains living microorganisms which, when applied to seeds, plant surfaces, or soil and promotes growth by increasing the supply or availability of primary nutrients to the host plant. Biofertilizers add nutrients through the natural processes of nitrogen fixation, solubilizing phosphorus, and stimulating plant growth through …
Edible Vaccines WHAT IS VACCINE? The vaccine is a biological preparation that improves immunity against a particular disease. It contains an agent that resembles a disease-causing microorganism and is often made from a weakened or killed form of microbe, its toxins or one of its surface proteins. The agent stimulates the body’s …
Human Immunodeficiency Virus (HIV) What is HIV? HIV stands for ‘human immunodeficiency virus’. It weakens a person’s immune system by destroying important cells that fight against disease and infection. HIV is a member of the genus Lentivirus, part of the family Retroviridae. It is the causative agent of AIDS. AIDS is a …
Cell inclusion Bodies Bacterial cell inclusion bodies are otherwise known as granules. Electron microscopic observation reported the presence of both organic and inorganic granules inside the bacterial cell. These granules function as energy storage and these are also involved in reducing osmotic pressure. Some of these granules are found freely moving in …
Immunological Techniques Most of the immunological techniques are based upon the antigen-antibody reactions. Precipitation reactions are one of the important reactions that occur when antigen and antibody come to contact. When a soluble antigen reacts with its antibody in the presence of NaCl at optimal temperature and pH, the antigen-antibody complex forms …
Terminology used in Basic Microbiology Aerobe = organisms that grow in the presence of atmospheric oxygen Anaerobe = grows in absence of free oxygen aerotolerant anaerobes = microbes that grow equally well whether or not oxygen is present facultative anaerobes = microbes that don’t require oxygen for growth but do grow better …
The Bacterial Cell Wall The cell wall is the outer most rigid structure which provides the structure to the bacterial cell. Moreover, it helps the cell by providing protection to the cell from osmotic lysis, toxic chemicals, and other pathogens. The chemical structure of the bacterial cell wall is similar in different …
Culture media used in microbiology Image Source: Sigma-Aldrich Nutrient agar(1% to 2%) –> Basal media in microbiology, Supports the growth of all non-fastidious organisms MacConkey Agar—> Differential media for Enterobacteriaceae ( i.e. Lactose fermenting and non-lactose fermenting) Mannitol Salt Agar–> Selective and indicator media for S. aureus Triple Sugar Iron(TSI) medium–> Differentiation …
Properties of Staphylococcus aureus Ability to grow aerobically and anaerobically, over a wide range of temperatures, and in the presence of a high concentration of salt; the latter is important because these bacteria are a common cause of food poisoning. Polysaccharide capsule that protects the bacteria from phagocytosis. Cell surface proteins (protein …