BioChem Lecture 4_Lipids Flashcards
(16 cards)
Define a lipid
A diverse and ubiquitous group of organic compounds that are insoluble in water but very soluble in organic solvents.
List the three glycerol based lipids and describe them
1) Triacylglycerols - three R groups bonded to the glycerol backbone
2) Pospholipids - 2 R groups and a phospho group bonded to the glycerol back bone
3) Glycolipids - 2 R groups and a sugar bonded to the glycerol back bone
Why are Linoleic and alpha Linolenic fatty acids essential to be consumed in the diet?
It is because human cells can not make fatty acids containing cis double bonds beyond position 9
Describe the difference between fats and oils
fats are saturated with hydrogens. Oils contain cis double bonds that “kink” their structure and prevent them from packing together densely and are there for liquid at room tempurature.
What are the 4 structural functions of phospolipids?
1) Cell membranes (mostly phosphitidal choline)
2) Lipoproteins
3) Pulmonary surfactant
4) Bile
Phospolipids serve as the precursors of which 3 second messengers?
PIP 3, PIP 4, Diacylglycerol (DAG)
What are the two main functions of Sphingolipids
1) act as a structural component of cell membranes and lipoproteins
2) Precursor of second messengers
List three purposes of glycosphingolipids
1) Regulation of cell interactions
2) Regulation of growth and development of cells
3) Antigenic properties (ie cell surface receptors against cholera, toxins, viruses, and microbes
What identifies a steroid
the fused ABCD ring system
What idenentifies a sterol?
A sterol is a steroid that has a hydroxyl bonded to position three on the A ring. Note the hydroxyl can be esterified to a fatty acid as in the transport form of cholesterol
What are eicosanoids
Eicosanoids are signaling molecules made from the oxidation of Aracadonic acid
What are the four major sub classes of eicosanoids and what are they?
Prostaglandins
Prostacyclins
Thromboxans
Leukotriens
They typically act in a paracrine or autocrine function it induce a cellular reponse.
Where are prostaglandins produced and what are their four functions
They are produced in mist tissues. their functions include: Control vasoconstriction/dilation, smooth muscle contraction/relaxation, induce labor, fever response
Where are prostacyclins produced and what is their function
They are produced in vessel endothelium and control vasodilation
Where are thromboxanes produced and what is their function
They are produced in platelets and they control vasoconstriction
What are leukotrines and what is their function
They are produced in cells of the immune system and they mediate the immune response (I believe this is another name for cytokines)
