• 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…

  • Biology

    Phylum Cnidaria/Coelenterata

    Kingdom: Animalia Habitat: aquatic, mostly marine. Habit: solitary or colonial. Each individual is known as zooid. Symmetry: radially symmetrical Grade of organization: tissue grade of organization. Germ layer: diploblastic, outer ectoderm and inner endoderm. Mesogloea separates these two layers. The body has a single opening called hypostome surrounded by sensory tentacles. Coelom: gastrovascular cavity or coelenteron. Nematocyst: organ for capturing and paralyzing pray, present in tentacles Nutrition: holozoic Digestion is both intracellular and extracellular. Respiration and excretion are accomplished by simple diffusion. Circulatory system: absent Nervous system: poorly develop Many forms exhibit polymorphism ie. Polyp and medusa Polyps are sessile, asexual stage Medusa are free swimming, sexual stage Metagenesis: asexual…

  • Biochemistry

    Phylum Porifera

    Kingdom: Animalia Habitat: Aquatic, mostly marine, few are terrestrial Habit: They are solitary or colonial. Grade of organization: cellular grade of body Shape: Body shape is variable, mostly cylinder shaped Symmetry: Asymmetrical or radially symmetrical. Germ layer: Diploblastic animals. The adult body wall contains two layers, outer dermal layer and inner gastral layer. In between these two layers, there is a gelatinous and non-cellular mesoglea containing numerous free amoeboid cells. Coelom: Absent; acoelomate but spongocoel is present Surface of the body has numerous perforation called ostia (for the entry of water) and a large pore at the apex called osculum (for the exit of water). Water canal system present Endoskeleton:…

  • 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…

  • Human anatomy

    Human Eye: Anatomy, parts and structure

    The eye is the photo-receptor organ. Size and shape: Human eye is spherical about 2.5 cm in diameter. Location: it is situated on an orbit of skull and is supplied by optic nerve. There are 6 sets of muscles attached to outer surface of eyeball which helps to rotate it in different direction. Four sets of these muscles are straight muscles; superior, inferior, medial and lateral rectal muscle and two sets are oblique muscles; superior and inferior oblique muscles. Structurally two eyes are separated but some of their activities are coordinated so that they function as a pair. Anatomical structure of Eye Eye ball consists of three layers Outer fibrous…

  • Biology

    EVOLUTION

    Theory of Special Creation: According to this theory, life originated on this earth from supernatural powers like the god.  He created all plants and animals, which appeared on earth in the form they exist today. Theory of Spontaneous generation or Abiogenesis: According to this theory, life originated on earth from non-living objects spontaneously by a process called Abiogenesis (origin of life from non-living matter).  It was believed that fishes and frogs originated from mud, maggots arouse from decaying meat and insects from plant juices and microorganisms from air & water.  But later Louis Pasteur disproved this theory and stated that life originates from pre-existing life. Conditions of Primitive earth/ Origin of life: It is…

  • Biology,  Botony

    KINGDOM FUNGI

    Position of Fungi During warm humid days slices of bread, chapati, leather belts or shoes, etc. develop powdery layer on them. In lawns and flower beds, mushrooms come out. These are all fungi. Fungi were earlier classified as plants without chlorophyll and without differentiation of parts into root, stem and leaves. They are now included, in a separate Kingdom Fungi. Characteristics of Fungi Fungi are multicellular eukaryotes Fungi exist as the slender thread-like filaments called hyphae. Hypha has many nuclei. Yeast, however, is single-celled. The cell walls are made of chitin A hypha may be divided into cells by partitions called septa. Septa have pores through which cytoplasm streams freely.…

  • Zoology

    KINGDOM PROTOCTISTA (UNICELLULAR EUKARYOTES)

    Protoctista is unicellular eukaryotes. Protozoa and diatoms and algae are included in it. They have membrane-bound organelles such as nucleus with chromosomes enclosed in the nuclear membrane, mitochondria, chloroplast (in photosynthetic protoctists only), Golgi bodies and endoplasmic reticulum. Mitochondria are the respiratory organelles. Protoctists are either photosynthetic, parasitic or saprotrophic. For locomotion, protoctists may have cilia or flagella (Fig.) having 9 + 2 microtubules unlike those of bacteria, which have the 9 + 1 arrangement of microtubules. They reproduce both asexually and sexually. Some protoctists are beneficial to humans while others are harmful. Classification of Protoctista The kingdom Protoctista includes – 1. Phylum Protozoa which has the following four classes…