Structures and functions of CELL.

Cell membrane or Plasma membrane;

                                                                        Cell membrane is present in all prokaryotic and eukaryotic cells and this membrane is thin and elastic type cell membrane.It works like a semipermeable barrier and allowing a very few molecule in it.Cell membrane maintain the internal composition of cell.Cell membrane can also sense chemical message and can identify other cell.Fluid mosaic model is the model in which there is a lipid bilayer and protein molecule are collect strongly in it.This lipid bilayer gives fluidity and elasticity to membrane.In eukaryotic cell ,cholastrol also present in lipid bilayer.In eukaryotic cell many organelles for example, Mitochondria, Chloroplast, Golgi apparatus are also  bounded by cell membrane.

Cytoplasm;

                   Cytoplasm is a semi-viscous and semi transparent substance and present between plasma membrane (cell membrane) and nuclear envalop (a double membrane by which nucleus is bounded ).It contains water in which many organic molecules (like proteins carbohydrates and lipids ) and inorganic salts are completely or partially dissolved.Cytoplasm provides space for the proper functioning of organelles and also act as the various biochemical (metabolic) reaction.For example, Glycolysis (break down of glucose during cellular respiration) occurs in cytoplasm.

Cytoskeleton;

                             Cytoskeleton is a network of microfilaments and microtubules. Microtubules are made of  tubulin protein and are used by cells to hold their shapes.They are also the majer components of cilia (moves back and forth) and flagella (latin word meaning whip). Microfilaments are thinner and are made of actin protein. They help cells to change their shapes.

Cell organelles;

                                Organelles are small structure with in cells that perform dedicated functions. There are about the dozen types of organelles commonly founds in eukaryotic cells.Some important organelles are present below;

1. Nucleus: A prominent nucleus occurs in eukaryotic cells. In animal cells it is present in the center while in mature plant cells, due to the formation  of large central vacuole, it is pushed to side. Nucleus is bounded by double membrane is nucleur envelope. inside nucleur envelope granular fluid like nucleoplasm is present. Nucleoplasm contain one or two nucleoli and chromosomes.
2. Ribosomes : Ribosomes are tiny granular structures that are either floating freely in cytoplasm or are bound to endoplasmic reticulum . Ribosomes are not bound by membranes and so are found in prokaruotes. Ribosomes are the protien synthesis.