Strongyloides stercoralis is a parasitic roundworm that causes strongyloidiasis. It is commonly called a threadworm in the US. It is the smallest nematode known to cause infection in humans. They are unique among nematode because it has both parasitic and free-living form. Image Source: The Australian Society for Parasitology and CDC. … Read more
Fasciola hepatica is also known as a common liver fluke or sheep liver fluke. It causes hepatic fibrosis in ruminants and humans known as Fascioliasis. History and distribution of Fasciola hepatica Fasciola hepatica was the first fluke or trematode that was discovered more than 600 years ago in 1379 by … Read more
Ammonia is a toxic product to the body of animals, thus ammonia is continuously excreted from the body of the animals, in various from depending upon the external environment and physiology of animals. Types of animal-based on excretion of nitrogenous waste There are different types of nitrogenous waste products in … Read more
What is Mucormycosis? Mucormycosis is an infection caused by several species of filamentous molds belonging to the order Mucorales. The infections usually occur in immunocompromised individuals with one or more underlying conditions. The fungi responsible for these infections are found in different environmental niches like soil, decaying vegetables, bread, and … Read more
For examination in June and November 2022, 2023, and 2024. Image Credit: Cambridge Assessment International Education. Candidates for Cambridge International AS Level Biology study the following topics: 1. Cell structure 1.1 The microscope in cell studies 1.2 Cells as the basic units of living organisms cell surface membrane nucleus, nuclear … Read more
Benedict’s test for reducing sugars Definition Benedict’s test is a biochemical test performed to distinguish reducing sugars (monosaccharides and some disaccharides) from non-reducing sugars. Objectives To detect the presence of simple carbohydrates in a solution. To distinguish between reducing and non-reducing sugars. Principle The carbohydrates having a free or potentially … Read more
Water Definition Water is an inorganic liquid chemical that is colorless, odorless, tasteless that makes up most of the Earth’s hydrosphere and the fluids in the body of all living beings. Water is an extremely important component for the existence of life as it is vital for all biological processes. … Read more
Carbohydrates Definition Carbohydrates are a large group of organic compounds consisting of carbon, hydrogen, and oxygen which can be typically broken down into monomers to release energy in living beings. These are the most abundant biomolecules in the living body in terms of mass. Carbohydrates are also known as saccharides … Read more
Amino acids and their structure Proteins are macromolecules made up of monomers called amino acids. Amino acids are the building block of all proteins. An amino acid is a simple organic compound consisting of a basic group (-NH2), an acidic group (-COOH), and an organic R group that is unique … Read more
What are Lipids? Lipids are a group of diverse macromolecules consisting of fatty acids and their derivatives that are insoluble in water but soluble in organic solvents. Lipids consist of fats, oils, hormones, and certain components of membranes that are grouped together because of their hydrophobic interactions. The lipids are essential constituents … Read more
Enzymes Definition An enzyme is a protein biomolecule that acts as a biocatalyst by regulating the rate of various metabolic reactions without itself being altered in the process. The name ‘enzyme’ literally means ‘in yeast’, and this was referred to denote one of the most important reactions involved in the … Read more
Factors that affect enzyme action Enzymes are biological catalysts that accelerate the rate of chemical reactions in the biological system of living beings. Like catalysts, enzymes are also affected by a number of factors that regulate enzyme action. These factors are related to the chemical nature of enzymes as enzymes … Read more
What are Enzyme Inhibitors? Inhibitors are compounds that convert the enzymes into inactive substances and thus adversely affect the rate of enzymatically-catalyzed reaction is called an enzyme inhibitor, and the process involved is termed enzyme inhibition. Some enzyme inhibitors are normal body metabolites that inhibit a particular enzyme while other … Read more
Here are some of the best A Level Biology Books that we can study which are useful for examination from 2022. Book Cover page sources: Respective Books Website. Disclaimer: Books cover page, information, and table of contents are only used for educational purposes. If there are any copyright issues regarding the images, … Read more
What is Nucleus? Nucleus Properties The Nucleus is an important cell organelle that is present in the eukaryotic cell. It is derived from the Latin word, ‘nucleus’ or ‘ nuculeus’. It means kernel or seed. It is first described by Robert Brown as the cell organelle. It was named chromatin … Read more
Cell membrane (Plasma membrane) The outer thin membrane or the layer of the living cell is known as the cell membrane. It is also known as the plasma membrane in animal cells. In the plant cells, it is known as plasmalemma. The term cell membrane was given by Nageli and … Read more
Mitochondria Properties Mitochondria is the cell organelle which is filamentous and granular structure. It is present in higher plants, animals, and some microorganisms. It is absent in bacteria but is found in algae, protozoa, and fungi. To carry out the energy metabolism, mitochondria have got the lipoprotein framework. It consists … Read more
Golgi body Properties Golgi body or complex is an organelle that is bound by a membrane in eukaryotic cells. The Golgi body is also called as Golgi apparatus, Golgi complex, lipochondrion, Barker’s body, Dalton Complex, and Apparato Reticulare. Golgi complex may have distinct subunits called Golgiosomes, idiosomes, or dictyosomes. It … Read more
Endoplasmic Reticulum (ER) In 1897, Garnier observed the Endoplasmic Reticulum (ER) with a light microscope. Ergastoplasm was the term coined by him. In 1945 Porter first reported the Endoplasmic Reticulum. It was discovered independently by Porter and Thompson. It is a continuous membrane system. At one end, it connects the … Read more