Biology

Respiration in Plants * Respiration provides oxygen, which is used for the oxidation of food to provide energy. * Plants respire through small openings called the stomata on leaves and lenticels on stems and roots. * Cellular respiration involves breakdown of the C-C bonds of compounds of food. It takes place in the cytoplasm and ... Read more

Photosynthesis * Photosynthesis is a physiochemical process in which light is used to prepare food. * Cornelius Van Niel found that photosynthesis is a light-dependent reaction in which a hydrogen atom reduces carbon dioxide to form carbohydrates. * He also inferred that water is the hydrogen donor which is oxidised O2. * Chloroplast is found ... Read more

Essential Nutrients of Plants * Nutrition is the process of absorption of various minerals ions for growth. * The elements essential for plant growth are further divided into macronutrients and micronutrients. * The elements that are required by a plant in large amounts are called macronutrients. * The elements that are required in minute quantities ... Read more

Means of Transport * Diffusion, facilitated diffusion and active transport are three means of transport in plants. * Diffusion is a passive process; it requires no expenditure of energy. * Diffusion facilitated by proteins without any energy expenditure is referred to as facilitated transport. * Unlike diffusion, active transport requires energy to move molecules against ... Read more

Cell Cycle * All organisms, even the largest, begin life from a single cell. * The series of events by which a cell duplicates its genome, synthesises its constituents and eventually divides to form two daughter cells is known as the cell cycle. * The cell cycle is divided into two basic phases-the interphase and ... Read more

Chemical Composition of Biomolecules * All the carbon compounds derived from living tissues are called biomolecules. * In biology, the functional groups of organic chemistry are present as amino acids, fatty acids and nucleotide bases. * In alpha amino acids, the amino group and carboxylic group are present on the same αcarbon atom of the ... Read more

An Overview of Cell * Cell is the fundamental unit of life in all living organisms. * Modern cell theory states that:    • Living organisms are composed of cells and products of cells.    • Cells arise from pre-existing cells. * The plant cell is surrounded by a cell wall on the outside and ... Read more

Epithelial Tissues * Animal tissues are broadly classified into four types, namely epithelial connective, muscular and neural. * Epithelial cells are compactly arranged with little intercellular matrix. * The epithelium and other tissues have three types of specialised junctions, namely tight, adhering and gap junctions. * Simple epithelium consists of a single layer of cells ... Read more