1.Why do Bacteria and yeast synthesize fatty acids with more cis-double bonds when surrounding temperature drops?
2.Despite fluidity of bilayer, why do liposomes not fuse spontaneously with one another?
1. Bacteria and yeast synthesize fatty acids with more cis-double bonds when the surrounding temperature drops as a way to maintain an optimal level of fluidity in their cell membranes. The fluidity of the cell membrane is crucial for the proper functioning of various cellular processes. In colder temperatures, the lipid molecules in the membrane tend to pack tightly together, reducing the fluidity of the membrane. By incorporating more cis-double bonds into the fatty acids, the bacterial and yeast cells can prevent tight packing of the lipid molecules and maintain a suitable level of membrane fluidity.
To understand this phenomenon more comprehensively, you may dive into the field of molecular biology and explore the concept of fatty acid biosynthesis. By studying the enzymes involved in fatty acid synthesis and their regulation, you can understand how organisms adjust their fatty acid composition to adapt to changing temperature conditions.
2. Despite the fluidity of the bilayer, liposomes do not fuse spontaneously with one another due to the presence of electrostatic repulsion and the need for specific recognition factors. Liposomes are artificial lipid vesicles formed by self-assembly of phospholipids in an aqueous environment. They resemble natural cell membranes and can encapsulate various substances.
Liposomes consist of a lipid bilayer, with the hydrophilic heads facing the aqueous environment and the hydrophobic tails facing inward, creating a stable structure. While the fluidity of the bilayer allows movement of lipids, spontaneous fusion between liposomes is rare.
The main reason for the lack of spontaneous fusion is electrostatic repulsion. Lipid molecules in the bilayer have charged groups, such as phosphate groups in phospholipids, which create a repulsive force between liposomes. This repulsion prevents them from merging and undergoing fusion.
Additionally, liposomes require specific recognition factors to initiate fusion. These can be either proteins or other molecules present on the surface of the liposome. These recognition factors allow liposomes to interact and fuse selectively only when specific conditions are met.
To gain a deeper understanding of liposome fusion, you can explore the field of membrane biophysics and membrane fusion processes. Research on lipid bilayers, liposome composition, and the role of proteins can provide further insights into the factors governing liposome fusion.