cell size is important to understand because a cell cannot be extremely small or extremely large. This is because of the definitions of life, which state that in order to be classified as a living organism, that organism must maintain homeostasis, have the capacity to grow, respond to stimuli, and reproduce. Another key point in regulating cell size is the volume ratio And The Relation To The Rate Of Diffusion">surface area to volume ratio which keeps the cell proportional.
It is unlikely that something smaller than 0.1um would be considered a living organism because in order to be classified as living, the cell must contain all of the necessary components that are needed to maintain cellular metabolism. Living organisms must be able to carry out homeostasis and have the capacity to grow. Also, they must be able to, in some way, respond to stimuli and have the ability to reproduce whether they are asexual or sexual. Additionally, the approximate size of mitochondria are 1.0um to 10um. With that being said, how would you expect it to fit in a cell smaller than 0.1um?
Living organisms including all plants and animals require ... respiration where large molecules are broken down into smaller ones with energy released. An example of an ... is a commonly used respiratory substrate in intestinal epithelial cells in animals to provide energy for useful work. ... require the translocation of glucose (as sucrose) from source cells to sinks (roots, fruits and shoots) to provide ...
Just as a cell cannot be too small, it cannot be too large either. An animal cell cannot reach a size larger than 1000um because most animal cells are measured at 10um to 100um, which is nowhere near 1000um. The reason cells can only be but so large is because of the surface area to volume ratio. The surface area to volume ratio keeps cell size maintained by adjusting as the cell grows, enabling the cell to carry out the processes important for living organisms. A surface area that has been increased may lead to problems within the cell. If a cell becomes too large, then it would not be able to supply nutrients efficiently within the cell body. So this is why cells must remain small so that the cell membrane can adequately provide the interior of the cell with nutrients so that the cell may function properly in any environment.
All of these processes play a huge role in keeping the cell maintained and regulated. Without any of these, the cell would not survive. So, it is important that all of these work together in keeping and maintaining the cell so that life can be possible.