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AS and A Level: Molecules & Cells

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  1. Food Test. Aim: To conduct tests for reducing and non-reducing sugars, starch, lipids and proteins

    Also, in this experiment, the observations during each food test would be recorded and the colour changes would be observed to identify whether each food contain any of the macromolecules which are being tested. Materials/Apparatus: * Glucose solution * Sucrose solution * Starch solution * Iodine/ Potassium Iodide solution * Copper Sulphate solution * Sodium Hydrogen Carbonate solution * Ethanol (90%) * Potassium Hydroxide * Cold water * Vegetable oil * Egg albumen * Bread crumbs * Crushed potato * Test tubes * Test tube holders * Test tube rack * Measuring cylinder * Water bath * Pasteur pipette (dropper)

    • Word count: 1336
  2. The effect of alcohol on the stability of cell membranes-plan for an experiment.

    If and when for any reason the tonoplast is damaged, the various parts of the vacuole will leak out into the surrounding environment. The sharpness of the red color within the environment must be similar to the amount of cellular damage of which the beetroot has gained. This experiment enables me to test the effect of three very different alcohols (methanol, ethanol, as well as 1-propanol) on cell membranes. These alcohols are found within alcoholic beverages of which are taken in social environment.

    • Word count: 2587
  3. The lymphatic system during ill health

    * Lymph leaks out of the blood vessels * Accumulates in the spaces between the cells of body tissues. * Microorganisms are neutralised * Destroyed in the lymph nodes by white blood cells. * The lymph nodes are not swollen like how they do be whilst the body is fighting an infection * All sinuses are clear, however in the nose there is still mucus lining it to trap foreign particles from the air.

    • Word count: 414
  4. Classifying Microorganisms by Experiment

    On the other hand, due to the fact that gram negative bacteria have a strong outer membrane the crystal violet is not absorbed. Usually a counter stain - generally Safranin- is added to the slides after the crystal violet, all gram negative bacteria have a red or pink colour due to the Safranin. Also, according to the gram staining results along with the shape combination, the bacteria species could be identified. In this case, the observation we made was purple and long rod in appearance.

    • Word count: 981
  5. Report comparing different growth media, aseptic techniques and laboratory safety with own experiences

    Contact with broken glassware is prohibited and decontamination of sharp material before disposal is strictly required. Therefore, category 2 laboratories are required to provide special safety facilities and equipment such as the laminar flow cabinet which provides a sterile - particle-free- working environment with the help of air projecting through a system of filtration and carrying it across a working surface in a laminar air stream. There are three classes in biosafety cabinets, class I & II can be used in group 1,2 & 3 Microbiology Laboratories; whereas a class III cabinet will be used in a group 4 Microbiology Laboratory.

    • Word count: 1055
  6. Protein Synthesis and Chemotaxis in Bacteria

    Here, the amino acid sequence is read and the guidelines are translated to form polypeptide chain (protein). Some modifications could occur in the Rough Endoplasmic Reticulum; these could be the addition of carbohydrates on to certain amino acids in protein. A few sugar groups could be attached to the chain of protein. This helps the folding process of protein to occur correctly and helps to stabilize the structure of it.

    • Word count: 543
  7. Organelles in animal cells and bacteria cells

    The layer of peptidoglycan in the cell wall differs from gram-positive bacteria (thick- multi layered) to gram-negative bacteria (thin- single layered). Capsule: Not all bacteria cells possess a capsule. It is an additional layer and surrounds the cell wall. Its functions are; shielding and protecting the cell when engulfed by another organism, aiding in the maintenance of the moisture of the cell, and helping the cell to bind to surfaces and nutrients. Mesosome: These structures are formed by the infolding?s of the plasma membrane in prokaryotic cells which perform aerobic cellular respiration and they are distinctive structures from eukaryotic cells. The enzymes linked with respiration are placed within these folding?s and they perform cellular respiration.

    • Word count: 953

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