• Botony

    NITROGEN METABOLISM

    All the living organisms are basically composed of carbon, hydrogen, oxygen, nitrogen and many other forms of chemical elements. These elements contribute to finally organize various biomolecules present in a cell. Nitrogen is next to carbon in importance in living organisms. In a living cell, nitrogen is an important constituent of amino acids, proteins, enzymes, vitamins, alkaloids and some growth hormones. Therefore, study of nitrogen metabolism is absolutely essential because the entire life process is dependent on these nitrogen-containing molecules. MOLECULAR NITROGEN Nitrogen is primarily present in the atmosphere freely as dinitrogen or nitrogen gas. It is present in the combined form as Chile saltpetre or sodium nitrate and Chile…

  • Biochemistry

    BIOTECHNOLOGY

    The word biotechnology has come from two words, bios (meaning biology) and technology (meaning technological application). Thus biotechnology is defined as the industrial application of living organisms and their biological processes such as biochemistry, microbiology, and genetic engineering, in order to make best use of the microorganisms for the benefit of mankind. Biotechnology is applied in many areas to produce foods and medicines, in the development of new diagnostic tools, gene therapy, and DNA finger-printing for forensic purposes. Applications of Biotechnology 1. Health and medicine Fighting infectious diseases: Biotechnology is used extensively in the study of infectious diseases such as SARS (Severe Acute Respiratory Syndrome), and influenza. As a result, more…

  • Biochemistry

    ORIGIN OF LIFE

    The earth was formed about five billion years ago. At that time it was extremely hot. The existence of life in any form at that high temperature was not possible. As such, two questions arise pertaining to life: 1. How did life originate on earth? 2. How did primitive organisms evolve into new forms resulting in the evolution of a variety of organisms on earth? Origin of life means the appearance of simplest primordial life from nonliving matter. Evolution of life means the gradual formation of complex organisms from simpler ones. Chemosynthetic Theory of Origin of Life Several theories have been put forth to explain the origin of life. The…

  • 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,  Zoology

    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 Pathway

    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…

  • 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 the skull and is supplied by the optic nerve. There are 6 sets of muscles attached to the outer surface of the eyeball which helps to rotate it in a 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. The anatomical structure of Eye Eyeball consists…

  • 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…

  • Biology,  Zoology

    KINGDOM MONERA

    Includes the bacteria and cyanobacteria (commonly called blue-green algae). Since only bacteria are prokaryotic (lacking a true nucleus), that is without nuclear membrane), monera is the only prokaryotic kingdom. Bacteria were the first organisms to evolve on planet earth afterlife originated around 3.5 billion years ago and were the only organisms on earth for almost the next two billion years. All bacteria and cyanobacteria are single-celled or unicellular (monere : single) Monerans are also the most numerous of all living organisms. https://youtu.be/uYZXWL6V7OU Structure of a bacterial cell The single-celled bacterium has a cell wall made of compound peptidoglycancovering the cell membrane; a single chromosome. The cell has ribosomes but nomembrane-bound…

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