Blood Groups CompatibilityBlood Groups Landsteiner discovered four blood groups in human beings based on the mutual compatibility of the antigens and antibodies. They are A, B, AB and O.A person having O blood group can give blood to all the groups and …

What is a Chloroplast and what is its FunctionPlastids : Plastids are organelles enclosed by a double membrane found in all plants.Historical Account : E.Heckel (1865) gave the term plastid. Plastids are largest cell organelles. Ultrastructure : Plastids…

Explain the Process of Excretion in PlantsExcretion in Plants Plants do not produce nitrogeneous wastes like urea and uric acid because extra amino acids and nucleotides are not formed. They produce other types of waste products, called secondary metabol…

What are the Organelles in a CellCell organelles : Small membrane bound structures, which perform a lot of chemical activities to support the function & structure of a cell, called cell organelles – Some important cell organelles are following –Endop…

Which Chromosome Determines Gender in HumansSex Determination It is a process by which the sex of a person is determined. Genetics is involved in the determination of the sex of a person, which is explained as follows :A male has one X chromosome and on…

What is the Meaning of Depletion of Ozone LayerOzone Depletion The amount of ozone in ozonosphere began to drop in 1980s. A spring time ozone hole (area of extreme thinness of ozone) was discovered over Antarctica in 1985 by Farman et al. Its area has b…

What is the Structure and Function of MitochondriaMitochondria : A single mitochondrion is present in unicellular green alga, Microsterias. Number of mitochondria varies from 50­–50,000 per cell. Mitochondria of a cell are collectively known as chondrio…

Explain the Mechanism of Urine FormationMechanism of Urine Formation It has four steps – ultra filtration, selective reabsorption,  secretion and concentration. (i)   Ultra Filtration. Blood flows inside glomerulus under pressure due to narrowness of ef…

Structure and Function of the NephronStructure of NephronEach nephron consists of a round malpighian body formed by Bowman’s capsule filled with capillary net work afferent and efferent arterioles. Afferent means incoming, Efferent means outgoing called…

What is the Meaning of Evolution in BiologyEvolution or organic evolution (Spencer, 1852) is the unfolding of nature wherein newer types of organisms develop from the pre-existing ones through modification.Acquired Traits : Acquired traits are those vari…