• Human anatomy

    An Overview On Pineal Gland

    The pineal gland is a small, pea-shaped gland in the brain. Its function isn’t fully understood. Researchers do know that it produces and regulates some hormones, including melatonin. It is ectodermal in origin. It is unpaired (Single) and is attached to epithalamus of the diencephalon. It is, therefore, also known as Epiphysis cerebri (Pituitary, attached to the hypothalamus, is called Hypophysis cerebri) It is considered to be the ‘seat of soul’. In a human, it starts degenerating at the age of 7-8 years. The calcium and magnesium salts are deposited in this gland at later stages and the structure is then known as ‘brain sand’. This gland produces single hormone…

  • Biochemistry

    What is Prion?

    Prion, an abnormal form of a normally harmless protein found in the brain that is responsible for a variety of fatal neurodegenerative diseases of animals, including humans, called transmissible spongiform encephalopathies. In the early 1980s American neurologist, Stanley B. Prusiner and colleagues identified the “proteinaceous infectious particle,” a name that was shortened to “prion” (pronounced “pree-on”). Prions can enter the brain through infection, or they can arise from mutations in the gene that encodes the protein. Once present in the brain prions multiplies by inducing benign proteins to refold into the abnormal shape. This mechanism is not fully understood, but another protein normally found in the body may also be…

  • Microbiology

    Morphology of Bacteria

    Size The unit of measurement used in bacteriology is the micron (micrometre) 1 micron (μ) or micrometre (μm) – one-thousandth of a millimetre 1 millimicron (mμ) or nanometer (nm) – one-thousandth of a micron or one-millionth of a millimetre 1 Angstrom unit (Å) – one-tenth of a nanometer The limit of resolution with the unaided eye is about 200 microns. Bacteria aresmaller which can be visualized only under magnification. Bacteria come in a great many sizes and several shapes. Most bacteria range from 0.2 to 2.0 μm in diameter and from 2 to 8 μm in length. (anoverall average size of 1 to 10 μm.) Shape Depending on their shape,…

  • Human alimentary tract
    Biology,  Human anatomy

    Human Digestive Enzymes

    Human digestive enzymes are mainly synthesized in the salivary glands and in the pancreas As we’ve discussed, enzymes are made up of amino acids found in proteins so a ready supply of these building blocks is required to ensure there are optimal levels of digestive enzymes at all times. Digestive enzymes are mixed in the saliva and pancreatic juices and are released into the mouth and small intestines, respectively, to support digestion of proteins, fats, and carbohydrates. Their synthesis and release occur via carefully orchestrated and tightly controlled hormone systems that are activated not just when food hits our taste buds but also by the sight, smell and sound of…

  • Q & A

    Q & A on Cell Structure

    Q: What is cell theory? Cell theory asserts that the cell is the constituent unit of living beings. Before the discovery of the cell, it was not recognized that living beings were made of building blocks like cells. The cell theory is one of the basic theories of Biology. Q:  Are there living beings without cells? Viruses are considered the only living beings that do not have cells. Viruses are constituted by genetic material (DNA or RNA) enwrapped by a protein capsule. They do not have membranes and cell organelles nor do they have self-metabolism. Q:  In 1665 Robert Hooke, an English scientist, published his book Micrographia, in which he…

  • A level biology

    What is the function of Golgi body?

    The Golgi body is actually a pile or stack of membranous structures called cisternae. The numbers of cisternae in a single stack vary between 6-8. In some protists, however, the number could extend up to 60. The Golgi bodies are found in both plant & animal cells. The cisternae of Golgi body have four structural components i.e., cis-Golgi, endo-Golgi, medial-Golgi and trans-Golgi. The vesicles extending from endoplasmic reticulum fuse with the network. These vesicles then enter the stacks of Golgi body and finally reach the trans-Golgi. The different regions of Golgi apparatus contain different types of enzymes. These enzymes have certain specific tasks assigned to them. Vesicles leave the Golgi…

  • A level biology,  Biology,  Cell biology

    Animal Cell

    All animal cells are multicellular. They are eukaryotic cells. Animal cells are surrounded by a plasma membrane and it contains the nucleus and organelles that are membrane-bound. Unlike the eukaryotic cells of plants and fungi, animal cells do not have a cell wall. This feature was lost in the distant past by the single-celled organisms that gave rise to the kingdom Animalia. Animal cells are of various sizes and have irregular shapes. Most of the cells size range between 1 and 100 micrometers and are visible only with the microscope. Trillions of cells are found in the human body. There are many different types of cells, approximately 210 distinct cell types…

  • A level biology,  Biology

    Microscopy

    Of all the techniques used in biology, microscopy is probably the most important. The vast majority of living organisms are too small to be seen in any detail with the human eye and cells and their organelles can only be seen with the aid of a microscope.  Cells were first seen in 1665 by Robert Hooke (who named them after monks’ cells in a monastery) and were studied in more detail by Leeuwenhoek using a primitive microscope. Units of measurement: Metre  (m) = 1 m Millimetre  mm = 10-3 m Micrometre   µm = 10-6 m Nanometre    nm = 10-9 m Magnification and Resolution By using more lenses microscopes can achieve…

  • Biology

    FIVE KINGDOM SYSTEM

    In this lesson, we discussing five kingdom classification. Five kingdom classification is proposed by R.H.Whittaker in 1969. the kingdom defined by him were named Monera, Protista, Fungi, Plantae, and Animalia. In this lesson, we show a brief introduction to these kingdoms for more information on kingdom please visit a particular lesson on that kingdom. Main Criteria used for this classification are cell structure, thallus organization, mode of nutrients, reproduction and phylogenetic relationship. Besides these major characteristics, he has also given importance to characters of ecological role-played and mode of reproduction. Major criteria on which five-kingdom classification is based Criterion Kingdom Monera Protista Plantae Fungi Animalia Cell type Prokaryotic Eukaryotic Eukaryotic Eukaryotic Eukaryotic…

  • Biology,  Genetics,  Q & A

    What is the Biological function of DNA

    DNA polymers direct the production of other polymers called proteins A protein is one or more polymers of monomers called amino acids. Proteins are the workhorse molecules in your cells. They act as enzymes, structural support, hormones, and a whole host of other functional molecules. All traits derive from the interactions of proteins with each other and the surrounding environments. A chromosome consists of smaller segments called genes Chromosomes are very long structures consisting of two DNA polymers, joined together by hydrogen bonds connecting complementary base pairs. A chromosome is divided into segments of double-stranded DNA called genes. Image showing how a chromosome is made up of DNA which contains genes.…

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