Question

Cell Biology Mini-Tutorial: Membrane Synthesis and Intracellular Movement

Answer 1

Note: This is a reference for educational/studying purposes, not a question, please save all comments or questions for the end.

Answer 2

\({\bf{Lipid~Biosynthesis}}\)
- cells can only synthesize new membranes by expanding pre-existing ones (w/ some exceptions)
- general procedure: water-soluble membrane precursors > intermediates > lipid products > distribution of lipid products between membranes/organelles
- fatty acid synthesis: acetate > esterification > acetyl CoA
ex. saturated fatty acids made from acetyl CoA via acetyl CoA carboxylase and fatty acid synthase
unsaturated fatty acids: desaturase enzymes insert double bonds to de-saturate fatty acids
- fatty acid-binding proteins (FABPs) facilitate intracellular movement. have b-sheet lined hydrophobic "pocket" which can interact noncovalently w/ surrounding protein

\({\bf{Incorporation~into~Membrane}}\)
- must be converted to CoA esters
- then, enzymes convert acyl CoAs, glycerol 3-phosphate, and head group precursors for insertion into membrane
- finally, they are transported to the membrane/organelles
- sphingolipids are made from palmitoyl CoA and combined with another acyl group to form N-acyl sphingosine > polar head group added > sphingomyelin

\({\bf{Cholesterol~Synthesis}}\)
formation of HMG-CoA > conversion to mevalonate by HMG-CoA reductase > isopernoid conversion > then enzymes in the membrane do the final conversion steps

\({\bf{Transport~Mechanisms}}\)
1. vesicle budding
2. direct protein-mediated contact of membranes
3. lipase transfer proteins

Answer 3

This is the end of my tutorial; I hope you found it helpful. If you have any ∗relevant∗ comments or questions I will attempt to address them to the best of my ability.

Thank you for reading!