Lipids and membranes

  • Structural and nutrient substances

  • Found mainly in plasma, adipose tissue and biological membranes

  • Kinky unsaturated dont pack together as easily so have weaker intermolecular forces and therefore, lower the melting point.

  • Triglycerides are how we store fatty acids

  • 1g triglyceride= 6x energy store of glycogen

  • Acetyl-coA and NADPH—→ fatty acids (via synthases enzymes).takes place in cytoplasm of cell.

  • Non essential fatty acids (can be derived within the body and via foods we eat) pop example: oleic acid

  • Desaturate adds double bond to stearic acid to make oleic acid.

  • Most abundant fatty acid in human adipose tissue and second most across all human cells.

  • Essential fatty acids include alpha-linolenic acid and linolenic acid. Humans don’t have specific desaturate enzymes needed so we can’t make it.

  • Needed from diet

  • Phospholipids are class of lipids that are major component of all cell membranes with protein and cholesterol. Lipid belayers because of amphiphilic characteristic.

  • Glycolipids derived from sphingosine

  • Cerebroside is the simplest glycolipid. Contains single sugar residue (either glucose or galactose)

  • AMPHIPATHIC NATURE OF MOLECULES

  • Bimolecular sheet proffered by phospholipids than Michelle because 2 fatty acid chains are too bulky to fit into the interior of the micelle.

  • VDW between hydrocarbon tails and H binding between polar head groups and water

  • Glycolipdis are in assymtrif orientation and sugar residues are always on extra cellular side of ,embrace.

  • Cholesterol inserted into phospholipid bilayers. Acts as a buffer and maintains fluidity of cell membranes. Bilayers less fluid because it becomes more packed, so less permeable too.

  • Liver processes cholesterol and releases LDL which Carries cholesterol to cells that need it. Too much cholesterol can get deposited to arteries.

  • HDL picks up excess cholesterol from cells and artery walls and take it back to liver for removal or recycling. Protects the heart.

  • Lipid rafts are formed between cholesterol and specific lipids

  • They bring proteins fotgether that work together

  • liposomes are spherical sac of phospholipids that surround a water molecule. Can be loaded with hydrophobic or philioc molecules.

  • Concentrate in regions of increased blood circulation