• Biochemistry,  Q & A

    Q & A ON WATER AND MINERAL SALT

    Q1.  What is the approximate percentage (in mass) of water in the human body? Is this percentage expected to be larger in the adult or in the old individual?  Ans: Approximately 65% of the human individual mass is water. The brain, for example, has around 90% of water in mass, the muscles, 85%, and the bones have between 25% and 40% of water. Younger adult individuals have proportionally more water in mass than older individuals. Q2.  What are the main biological functions of water? Ans: Water is the fundamental solvent for chemical reactions of living beings; it is the main means of substance transportation in the cell and between cells…

  • Biochemistry,  Cell biology,  Genetics

    WHAT IS DNA?

    Deoxyribonucleic acid (DNA) is a molecule that carries most of the genetic instructions used in the development, functioning, and reproduction of all known living organisms and many viruses. DNA is a nucleic acid; alongside proteins and carbohydrates, nucleic acids compose the three major macromolecules essential for all known forms of life. DNA  stores instructions for making other large molecules, called proteins. These instructions are stored inside each of your cells, distributed among 46 long structures called chromosomes. These chromosomes are made up of thousands of shorter segments of DNA, called genes. Each gene stores the directions for making protein fragments, whole proteins, or multiple specific proteins. DNA is well-suited to…

  • Biochemistry,  Cell biology

    OXIDATIVE PHOSPHORYLATION, ELECTRON TRANSPORT CHAIN

    OXIDATIVE PHOSPHORYLATION It is the main source of energy of our cell. Takes place in Mitochondria. Movement of protons through inner mitochondrial membrane leads to ATP production DEFINITION Oxidative phosphorylation includes the coupling of the oxidation of NADH or FADH2 by the respiratory chain with the synthesis of ATP via gradient of protons across the inner mitochondrial membrane. ELECTRON TRANSPORT CHAIN An electron transport chain consists of a properly arranged & oriented set of electron carriers transporting electrons in a specific sequence from a reduced nicotinamide coenzyme (NADH) or a reduced flavin prosthetic group (FADH2) to molecular O2. The inner mitochondrial membrane carries an electron transport chain called the mitochondrial respiratory chain,…

  • Biology

    COENZYMES

    Enzymes may be simple proteins or complex enzymes. A complex enzyme contains a non-protein part, called a prosthetic group (co-enzymes). Coenzymes are heat stable low molecular weight organic compound. The combined form of protein and the co-enzyme are called as holo-enzyme. The heat labile or unstable part of the holo-enzyme is called as apo-enzyme. The apo-enzyme gives necessary three-dimensional structures required for the enzymatic chemical reaction. Co-enzymes are very essential for the biological activities of the enzyme. Co-enzymes combine loosely with apo-enzyme and are released easily by dialysis. Most of the co-enzymes are derivatives of vitamin B complex group of substance. One molecule of the co-enzyme with its enzyme is sufficient…

  • Biochemistry

    Krebs (Citric Acid) Cycle

    It is also known as TriCarboxylic Acid (TCA) cycle.  In prokaryotic cells, the citric acid cycle occurs in the cytoplasm; in eukaryotic cells, the citric acid cycle takes place in the matrix of the mitochondria. The cycle was first elucidated by scientist “Sir Hans Adolf Krebs” (1900 to 1981). He shared the Nobel Prize for physiology and Medicine in 1953 with Fritz Albert Lipmann, the father of ATP cycle. The process oxidises glucose derivatives, fatty acids and amino acids to carbon dioxide (CO2) through a series of enzyme controlled steps. The purpose of the Krebs Cycle is to collect (eight) high-energy electrons from these fuels by oxidising them, which are transported…

  • Biochemistry

    Glycolysis

    Carbohydrates are the first cellular constituents formed by photosynthetic organisms and result from the fixation of CO2 on the absorption of light. The carbohydrates are metabolized to yield a vast array of other organic compounds, many of which are subsequently utilized as dietary constituents by animals.The animals ingest great quantities of carbohydrates that can be either stored, or oxidized to obtain energy as ATP, or converted to lipids for more efficient energy storage or used for the synthesis of many cellular constituents. The major function of carbohydrates in metabolism is as a fuel to be oxidized and provide energy for other metabolic processes. The carbohydrate is utilized by cells mainly…