|If a cell's wall is not alive then how does the cell's wall grow?|
|Question Date: 2020-08-15|
Fantastic question! You may have learned that plant cell walls are made mostly of cellulose. Cellulose consists of thousands of glucose (sugar) molecules linked together to form a rigid structure. So, it makes complete sense that you are wondering how this rigid cell wall grows along with the cell. I personally study fish, not plants, so I actually had to read a scientific paper to find the answer!
The cell wall is able to expand as the cell grows because of changes in pH (acidity) that come from inside the cell. Within the cellulose structure of the cell wall there are embedded proteins called expansins that get loosened when the pH changes. The loosening of these proteins allows the cell wall to expand as the cell grows. I hope this answers your question. Keep asking great questions like this and you are on your way to becoming a scientist!
I'm sure that's confusing. The wall itself is sort of like a shell. The wall itself is not alive, but it is built and maintained by the living cell. Think of it as you knitting yourself a sweater. You needed to be alive to collect the materials and make them into a covering for yourself, but the sweater isn't alive. You can add rows of knitting to make your sweater bigger.
Plants are one type of living organism with cell walls. When a plant cell divides, it prepares by making the stuff the wall is made out of from raw materials. Then it moves the wall-building material around the cell using little bags of membrane (vesicles) and the cytoskeleton (wich acts like our bones and muscles). Then it moves these bags into a row to make a new wall that divides the old cell into two smaller ones. It's sort of like putting up a divider in the middle of a room.
It can add more wall material as the living cell grows by filling more bags (vesicles) with more stuff (cellulose) and moving them into place with the cytoskeleton.
Why do you think plant cells need cell walls when we animals don't have cell walls? Hint: Look back at what I said about the cytoskeleton.
Thanks for asking,
It depends on what you mean by alive. Your hair grows but would you say your hair is alive? On the one hand it is alive but on the other hand your hair would have a difficult time driving to the grocery store! Ha-ha.
So a better way to think about this is to recognize that a cell has different parts and these parts act together like the way the different musicians play music in an orchestra; the drummer has a part, the piano player has a part, the guitar player has a part and so does the singer. When they work together they produce something that is better than just the drums or singing. It is a complete whole made up of parts that work together in an organized manner.
So the cell wall has a function: it is to let in the things needed for functioning of the cells organelles and to pass out the waste products. The cell wall has a function that allows the nucleus of the cell to make DNA and allows the other interior parts of the cell to perform other needed functions.
What an interesting question! Plant cells grow by expanding their cell walls through a process called polymer creep. This process is a slow, time-dependent, and irreversible extension where the cells add cell walls' materials (mostly polysaccharides, which are chains of sugar) into their cell walls, therefore increasing cell walls' surface area or "growing" the cell walls.
Cell wall is indeed not alive. In higher plants (plants that are not algae), the cell wall is composed of cellulose, xylan, lignin, and various types of proteins. How compact those components are depends on the acidity of the extracellular space, the space outside of the cell membrane. A plant cell can pump out proton to increase the acidity in the extracellular space. In this way the cell wall is loosened and allow the cell to grow.
Our cells are alive, but the parts and pieces of our cells are not alive, by themselves.
"Primary cell walls characteristically extend (grow) by a mechanism called acid growth, mediated by expansins, extracellular proteins activated by acidic conditions that modify the hydrogen bonds between pectin and cellulose. This functions to increase cell wall extensibility."
They don't. Dead cells' walls do not grow. The way that plants grow more wood is that they have some kind of cambium, a layer or cylinder of tissue that is alive and that produces more wood cells, which then die as part of their development, while the living cambium continues to grow.
Click Here to return to the search form.