Biology

An allergy is a hypersensitive reaction to an antigen by the body. The antibody reacts with the antigen violently. People with allergies are oversensitive to foreign materials like dust, pollen grains, some foods, some drugs and some air pollutants. Allergic reactions lead to production of histamine by the body. Histamine causes swelling and pain. Allergic […]

A vaccine is a biological preparation designed to provide immunity against specific diseases. It contains weakened, inactive, or non-disease-causing forms of a pathogen, or fragments of it, which stimulate the immune system to recognize and respond to the actual pathogen. This process triggers the production of antibodies and the activation of immune cells, preparing the

There are four types of blood groups in human beings: A, B, AB and O. These are based on types of proteins on the cell membrane of red blood cells. There are two types of proteins denoted by the letters A and B which are antigens. In the plasma are antibodies specific to these antigens

Immune response is the production of antibodies in response to antigens. An antigen is any foreign material or organism that is introduced into the body and causes the production of antibodies. Antigens are protein in nature. An antibody is a protein whose structure is complementary to the antigen. This means that a specific antibody deals

Composition of Blood The mammalian blood is made up of fluid medium called plasma with substances dissolved in it. Cellular components suspended in plasma include; Erythrocytes (red blood cells), Leucocytes (white blood cells) Thrombocytes (platelets) Blood proteins. Plasma This is a pale yellow fluid consisting of 90% water. There are dissolved substances which include; Glucose,

Transpiration is the process by which plants lose water in the form of water vapour into the atmosphere. Water is lost through stomata, cuticle and lenticels. Stomatal transpiration: This accounts for 80-90% of the total transpiration in plants. Stomata are found on the leaves. Cuticular transpiration: The cuticle is found on the leaves, and a

Transport is the movement of substances within an organism. All living cells require oxygen and food for various metabolic processes. These substances must be transported to the cells. Metabolic processes in the cells produce excretory products which should be eliminated before they accumulate. The excretory products should be transported to sites of excretion. Organisms like

rgans that are involved with feeding in humans constitute the digestive system Digestive System and Associated Glands Human digestive system starts at the mouth and ends at the anus. This is the alimentary canal. Digestion takes place inside the lumen of the alimentary canal. The epithelial wall that faces the lumen has mucus glands (goblet cells).