Cells are complicated, so lets begin with a breakdown of the different parts inside them called organelles.
A plasma membrane is an essential component, usually made of proteins and lipids. It is found on the surface of cells but can also be found within a cell on membrane bound organelles. With various roles it is crucial for the membrane to operate efficiently. Damage to the membrane can in fact have terrible consequences. The key role is to regulate the movement of substances into and out of the cell. So you can picture it like a door. If the door is closed, no solid object can pass through (unless there is a hole), the door is impermeable. If we open the door slightly, then some smaller objects may pass through, it is partially permeable. If the door is wide open, we can then say it is permeable. Change in permeability can be useful in the exchange of substances such as ions.
The cell wall is a rigid structure found on the outside of plant cells. This is useful when dealing with cell turgidity. Composed of carbohydrates, mainly cellulose, this provides support for the cells. The brilliant thing about cell walls is that the provide a physical barrier, this helps prevent pathogenic microorganisms from entering, reducing the spread of disease. Furthermore, the cell wall participates in the movement of water (transpiration) as it begins the apoplast pathway. Now you may be wondering, why is it only plant cells that have a cell wall and not animals? Well the answer simply is, we do not need them. The rigid structure allows plants to stand upright as they do not have bones to do so. If our cells had cell walls, this would inhibit our ability to move, and we wouldn’t want that would we?
Next we have the nucleus, the first organelle to be discovered by scientists and the control centre of the cell. But do not be mistaken, most will assume that the nucleus is always located at the centre of a cell, this is not the case. They can be found in various places, however being too close to the cell wall is rather risky. The nucleus is a large organelle which is surrounded by a double membrane called the nuclear envelope. The nuclear envelope has pores called nuclear pores. You may be able to work this out already, but this allows the movement of substances in and out of the nucleus. Such substances can be messenger ribonucleic acid (mRNA) which is involved in the transcription of DNA. Inside the nuclear envelope is a nucleolus, this contains all the DNA the cell needs, like the coding for the protein to make another protein. And surprisingly the never-ending code only uses 4 letters! Lastly, chromatin is found inside the nucleus. It is a combination of DNA, RNA and proteins that make up the chromosomes. The nucleus is rather complicated, and only gets more complicated! We can perhaps call it the brain of the cell!
0 Comment:
Be the first one to comment on this article.