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AS and A Level: Molecules & Cells

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  1. Peer reviewed

    Why do they put mint in toothpaste? Would garlic be better?

    3 star(s)

    Equipment Agar plates seeded with bacteria Plant material (garlic cloves and mint leaves) Pestle and mortar 10cm3 industrial methylated spirits Pipette (sterile) Paper discs (e.g. Whatman antibiotic assay paper discs) Sterile Petri dish Sterile forceps Tape Marker pen Incubator set at 25�C Method 1. The agar plates had already been seeded and left to set for an hour before our practical by the school science technician. 2. We crushed 3g of a garlic glove using the pestle and mortar and 3g of mint leaves using a clean pestle and mortar.

    • Word count: 899
  2. Peer reviewed

    Testing the tensile strength of celery

    3 star(s)

    Apparatus * Celery * Knife * Clamp stand and clamp * Sticky tape * Weights and Weight holder. Method First of all, we were unable to do a control experiment with the celery because we did not have the apparatus. However, if we did, one possible method would be to damage the fibres by heating them, perhaps by placing them in boiling water for a few minutes. We would then use the following method. Initially, we cut the stem with a knife and gently peeled away fibres with the help of a mounted needle.

    • Word count: 530
  3. Peer reviewed

    Coronary Heart Disease

    3 star(s)

    There are also many different types of lipoproteins, but the main two are low density lipoproteins (LDL) and high density lipoproteins (HDL). LDL cholesterol builds up in the coronary arteries, which can then cause CHD as mentioned previously. Whereas HDL cholesterol does the opposite and takes the cholesterol away from the cells and back to the liver, thus this is often referred as the good cholesterol. A good total blood cholesterol level is 5 or lower, as if you allow your LDL level to get too high the HDL will not be to remove the cholesterol sufficiently.

    • Word count: 858

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