• Biochemistry,  Cell biology

    BLOOD CLOTTING (HAEMOSTASIS)

    The clot or coagulam is a dark -reddish-brown ‘scum’ formed mainly by a network of threads in which dead or damaged blood elements are trapped. It is the property of plasma. Normal blood clotting time is 3−10 min. The clot inside the blood vessels is called a thrombus. A moving thrombus is called embolus. In haemophilia (a sex-linked disease) the blood clotting is delayed. According to Macferlane hypothesis, there are 13−factors responsible for blood clotting (or coagulation). The 4−factors are primary and 9−factors are accessory for this process. Primary factors Fibrinogen Prothrombin Thromboplastin (Thrombokinase) Calcium ions  The first 3−factors are proteinaceous in nature. The Prothrombin (II factor) is synthesized in…

  • Biochemistry,  Biology,  Cell biology

    CARBOHYDRATES

    Micromolecules – Monosaccharides and Oligosaccharides (Including Disaccharides) Macromolecules – Polysaccharides The micromolecules have the molecular weight of < 1000 Daltons whereas the macromolecules have > 1000 Daltons as molecular weight. The average carbohydrate requirement in an adult is ~ 400g per day which provides about 50-70% of total energy. Essential elements in the constitution of carbohydrate – C. H. O General Formula – *Cx (H2O)y (Containing more than one-OH groups). The polyhydroxy aldehydes or ketones can also be called as saccharides 80% of the dry weight of the plant is carbohydrate. There are 3-categories/classes  of carbohydrates: Monosaccharides Oligosaccharides Polysaccharides Monosaccharides They are simplest carbohydrates, with 3 to 7 carbon atoms.…

  • Biochemistry

    MCQs ON PLANT KINGDOM

    1. Sexual reproduction involving the fusion of two cells in Chlamydomonas is (a) isogamy (b) homogamy (c) somatogamy (d) hologamy Answer and Explanation: 1. (d): Isogamy involves the fusion of gametes which are morphologically and physiologically similar. They are called isogametes. In Chlamydomonas, two vegetative cells may fuse to form a zygospore and the phenomenon is called as hologamy. As a result of fusion of two gametes, zygospore is formed. 2. Prothallus (gametophyte) gives rise to fern plant (sporophyte) without fertilization. It is (a) apospory (b) apogamy (c) parthenocarpy (d) parthenogenesis. Answer and Explanation: 2. (b): Prothallus (gametophyte) gives rise to fern plant (sporophyte) without fertilization. This phenomenon is called apogamy. Development…

  • Biochemistry,  Cell biology,  Q & A

    What is the function of the cell membrane?

    The cell membrane is otherwise called a Plasma membrane. It may be defined as the thin, elastic, semipermeable living membrane that serves as a boundary for the Cytoplasm. The Cell membrane is made up of glycoproteins and phospholipids. The Functions of the Cell membrane are as follows: Cell membrane or Plasma membrane is a semipermeable membrane present around the Protoplasm. It acts as a boundary to the cell. It gives a definite shape to the Cell. It gives Mechanical support to the Cell. It protects cell contents. It regulates the exchange of materials into and out of the cell. The Sites for cell recognition are located on the surface of the Plasma…

  • 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. Transport chain called the mitochondrial respiratory chain, which forms the final path for electron…

  • 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,  MCQ

    VARIETY OF LIFE

    Q1)  Any attribute or descriptive phrase, referring to form, structure or behaviour of a specific organism for a particular purpose is: A) Expression B) Specificity C) Character D) Nature E) None of the above Q2) Which one of the following is an example of “Expression of character”? A) Petal length B) Stem thickness C) Corolla colour D) Sepals colour green E) Leaf shape Q3) Living organisms having fundamental similarity in their structure are studied under: A) Biochemistry B) Anatomy C) Homology D) Heterology E) Cytology Q4) From evolutionary point of view, flipper and wing are believed to resemble human: A) Hand B) Foot C) Fingers D) Arm E) Leg Q5)…

  • Biochemistry,  MCQ

    ENZYMES

    Q1) Enzyme is a Greek word which means: A) in virus B) in bacteria C) in fungi D) in yeast E) in humans Q2) Who discovered that certain molecules of ribonucleic acid also function as enzymes? A) Friedrich Wilhem Kuhne only B) Friedrich and Thomas Cech C) Thomas Cech only D) Sidney Altman & Thomas Cech E) Sidney Altman only Q3) Molecule of ribonucleic acid which functions as enzymes are called: A) Increase energy of activation of reaction B) Maintain energy of activation of reaction C) Lower down energy of activation of reaction D) No effect on energy of activation of reaction E) Highly increase energy of activation of reaction…

  • Biochemistry

    HUMAN NERVOUS SYSTEM

    The origin of human nervous system is ectodermal. The whole nervous system is divided into three parts. Central Nervous System It comprises the brain and the spinal cord. Brain Brain accommodate in the skull while spinal cord is enclosed by the vertebral column. To support brain and protect it from external pressures, it is surrounded by a covering of triple membrane of connective tissue called the meninges. The three layers of meninges are duramater, arachnoid and piamater. The innermost layer, piamater is thin, delicate and highly vascular. It is firmly adhere to the brain. The middle layer is arachnoid membrane, which is thin and highly folded structure in front of…

  • 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,…