Question

1.How does the chemical structure of a Phospholipid lead to the formation of a membrane as seen in the cell?

Why is this structure semi-permeable?

  Prokaryotes have no membrane-bound organelles. Why does the organelle membrane matter?

Answer 1

Ans:-The cell membrane is composed of lipids that are arranged in a bilayer.Also,the lipids are arranged within the membrane with the polar head towards the outer sides and the hydrophobic tails towards the inner part.This ensures that the non polar tail of saturated hydrocarbon protect from the aqueous environment.The link component of the membrane mainly consists of phosphoglycerides.The quasi-fluid nature of lipid enables lateral movement of proteins within the overall bilayer.

Cell membrane allows or permits the entry and exit of some materials in and out of the cell.It also prevents movement of some other materials.The cell membrane,therefore,is called a selectively permeable membrane.some non polar substances like carbon dioxide or oxygen can move across the cell membrane by a process called diffusion as they are soluble in lipid bilayer.small uncharged polar molecule like water can cross the membrane by the process of osmosis but larger uncharged molecule such as glucose can't cross the membrane.

Prokaryotes have no membrane bound organelle but eukaryotes have membrane bound organelle.prokaryotic cells have no membrane-bound organelles ,their chromosomes are composed of only nucleic acid,they have only very small ribosomes as organelles.Membrane bound organelle matter the most because it encase the organelles and control the exchange of essential cell components.it facilitates their gate keeping function.organelles are more stable in membrane bound structure than in non-membrane bound structure.In non-membrane bound organelles ,organelles are in floating mode can be both avert and divert being destroyed by the chemical environment it functioned in.