• Question: Do all cells look the same?

    Asked by samsam to Amy, Andy on 24 Jun 2011.
    • Photo: Amy Reeve

      Amy Reeve answered on 24 Jun 2011:

      Hi Sam

      All the cells in our body generally have the same components, a nucleus, mitochondria, a cell membrane etc but they call all take on very different forms. Most of the time the shape of a cell reflects its function within an organ of the body.

      Brain cells for example have long processes called axons so they can communicate to other cells a long way away. The sciatic nerve reaches from your spinal cord all the way down to your toes!

      Muscle cells are long and thin and cluster together to allow contraction and relaxation of your muscles. Red blood cells don’t contain a nucleus or mitochondria so that they can carry as much oxygen as possible around your body.

      Thanks for your question 😀

    • Photo: Andy MacLeod

      Andy MacLeod answered on 24 Jun 2011:

      Hello again Sam

      As Amy mentioned, our cells mostly have the same bsic parts. They’re all bound by a cell membrane, and are full of cytoplasm. Most of them have a nucleus to hold the DNA (red blood cells don’t), they have mitochondria to make energy, ribosomes to tranlsate DNA code into the proteins that cells need to function, and various other vessels that transport proteins around the cell.

      But beyond that, they can vary widely in size and shape, depending on what tissue they’re part of, or even what function they have within that tissue. The DNA in the nucleus of all our cells is pretty much the same, but some genes get turned on or off by chemical signals as the embryo develops from a single cell into a person. There are special cells called “stem cells” that can develop into any other kind of tissue, depending on the chemical signals they receive. Scientist are trying to work out what these signals are, so they can use stem cells to regenerate tissues in the lab. But its difficult, as there are so many different genes to turn on and off, because there are so many different types of cell.

      Nerve cells can be long and thin to carry the signals from the brain all over the body:
      Red blood cells are little discs that carry the oxygen from the lungs to the rest of your body:
      White blood cells are the body’s defence against invaders, and can be different shapes

      And there are many, many other types, all of which have specific shapes to perform the specific function the body needs them to do.