A level biology

Cambridge International AS and A Level Biology build on the skills acquired at Cambridge IGCSE (or equivalent) level.

  • 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…

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