• Biochemistry

    Q & A on Cell Structure

    Q1: Which one of the following cell structures can be seen with a light microscope? (Mark 1) A. mitochondrion B. ribosome C. rough ER D. smooth ER Ans: (A) Mitochondrion Q2: The use of electrons as a source of radiation in the electron microscope allows high resolution to be achieved because electrons: (Mark 1) A. are negatively charged. B. can be focused using electromagnets. C have a very short wavelength. D travel at the speed of light. Ans: (C) have a very short wavelength. Q3: Which one of the following structures is found in animal cells, but not in plant cells? (Mark 1) A. cell surface membrane B. centriole C.…

  • 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…

  • Biochemistry,  Q & A

    Q & A ON CELL RESPIRATION

    1. How do cells obtain the energy they need to function? Cells obtain energy for their metabolic reactions from breaking down organic molecules with a high energy content. This energy is mostly stored as ATP molecules. The process of obtaining energy in order to produce ATP molecules is called cellular respiration. 2. What compound is phosphorylated for ATP formation? What is the resulting compound when ATP releases energy? ATP, or adenosine triphosphate, is formed after the binding of one phosphate molecule (phosphorylation) to one ADP (adenosine diphosphate) molecule. This is a process that stores energy in the produced ATP molecule. When ATP provides energy to the cellular metabolism, it releases…

  • 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…

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