Cell organelles are the tiny functional units that exist in cells – examples include the nucleus, the mitochondria, the chloroplasts, the ribosomes and the golgi body and endoplasmic reticulum (rough and smooth). A typical animal cell has a diameter of about 50 micrometers – a micrometer being one thousandth of a millimeter.
Cell organelles all fit inside the cell and are therefore all much smaller than this. The measurements we use to say how big they are include the micrometer but we also tend to use the nanometer, which is one thousandth of a micrometer. This allows us to more easily describe the sizes of the smaller organelles. For example, a cell nucleus can be about 10 micrometers in diameter but a ribosome is about 25 nanometres across. This is easier than saying 0.0025 micrometers.
A cell and the major, larger organelles can be seen with a light microscope but the smaller ones need to be viewed with an electron microscope.
Cell organelles all fit inside the cell and are therefore all much smaller than this. The measurements we use to say how big they are include the micrometer but we also tend to use the nanometer, which is one thousandth of a micrometer. This allows us to more easily describe the sizes of the smaller organelles. For example, a cell nucleus can be about 10 micrometers in diameter but a ribosome is about 25 nanometres across. This is easier than saying 0.0025 micrometers.
A cell and the major, larger organelles can be seen with a light microscope but the smaller ones need to be viewed with an electron microscope.
