Blake_Biochem_15_Lipids Flashcards
Define: Fatty Acids and Lipids
Fatty acids are hydrophobic hydrocarbon chains; are key components of lipids
Lipids are amphipathic molecules
Phospholipid (4 components)
- Fatty acid
- Backbone (glycerol or sphingosine)
- Phosphate
- Alcohol
Glycerol
3 carbon alcohol
Sphingosine
3 carbon alchohol with an amino group and two hydroxyl groups
fuel molecules are stored as:
TAGs - triacylglycerols
C18 fatty acid no double bond:
octadecanoic acid
C12 fatty acid with ONE double bond:
dodecenoic acid
C18 fatty acid with two double bonds
octadecadienoic acid
C12 fatty acid with three double bonds
dodecatrienoic acid
Fatty acids usually contain an _____ number of C atoms, typically between __ and __
even, 14, 24
Which C number is most common in biological systems?
Which conformation (cis or trans) is more common in biological systems?
16 and 18
cis
What determines the properties of fatty acids?
length of chain and degree of saturation
Which attributes of fatty acids will RAISE melting points?
More Branching
Longer Length
Saturation
Which attributes of fatty acids will LOWER melting points?
Less branching
Shorter Length
De-saturation
What are the names and C-numbers of the non-essential fatty acids?
why are they non-essential?
Palimate, 16; Stearate, 18
because the body produces them naturally
What are the names, C-numbers, and Omega counts of the essential Fatty acids?
why are they essential?
Linoleate, 18, w-6
Linolenate, 18, w-3
Arachidonate, 20, w-6
becuase the body does not produce them, they must be gathered from the diet.
Why can some archaea survive in extremely hot thermal vents?
because the ether linkage is more resistant to hydrolysis, and the branched, saturated hydrocarbons are more resistant to oxidation.
What are the three major classes of membrane lipids?
- Phospholipids (includes phosphoglyceride and sphingomyelin)
- Glycolipids (eg. Cerebroside)
- Cholesterol
What is the simplest phosphoglyceride?
In what amounts is it present in membranes?
why is it important?
Phosphatidate
Only in SMALL amounts.
because it is a key intermediate in the biosynthesis of other phosphoglycerides.
How do you name a phosphoglyceride that is derived from phosphatidate?
What are the 5 examples given in class?
phosphatidyl+functional group
phosphatidylserine phosphatidylcholine phosphatidylethanolamine phosphatidylinositol diphosphatidylglycerol (cardiolipin)
what is the significance of phosphatidylserine?
important for memory and cognition
what is the significance of phosphatidylcholine?
major constituent of cell membrane and pulmonary surfactant
what is the significance of phosphatidylethanolamine?
- composes 25% of all pholpholipids
- in human physiology, they are found particularly in nervous tissue such as the white matter of the brain.
what is the significance of phosphatidylinositol?
important in signaling and other functional activities in the eukaryotic cell.
what is the significance of diphosphatidylglycerol?
important component of the inner mitochondrial membrane
Sphingosine is an ____ _____ that contains a ____, _______ _____ ____
amino alcohol
long, unsaturated hydrocarbon chain
Sphingomyelin 3 things
- The phospholipid with a sphingosine backbone
- The amino group of the sphingosine backbone is linked to a fatty acid by an amide bond.
- It is found in animal cell membranes, especially in the membranous myelin sheath that surounds some nerve cell axons.
Glycolipids are derived from what backbone?
sphingosine
what is the difference between a Glycolipid and a Sphingolipid?
both contain the sphingosine backbone, but Glycolipids have a sugar group attached to the primary hydroxyl group
How are glycolipids oriented in the cell membrane?
Always with the sugar residue on the extracellular side.
What is the simplest glycolipid?
why is it the simplest?
what are more complex glycolipids called?
- Cerebroside
- contains a SINGLE sugar residue on the primary hydroxyl group.
- gangliosides - branched chain of as many as 7 sugar residues
Cerebrosides
the common name for a group of glycosphingolipids called monoglycosylceramides which are important components in animal muscle and nerve cell membranes.
Cholesterol (classification and general structure)
- a steriod
- present in eukaryotes but not prokaryotes
- built from 4 fused, saturated, hydrocarbon rings
cyclopentanoperhydrophenanthrene - ring system
Why is cholesterol considered a sterol?
Because of its C3-OH group and its branched, aliphatic side chain of 8-10 C atoms at C-17
What is the significance of Cholesterol?
- the most abundant steroid in animals
- a major component of the eukaryotic plasma membrane
- essentially absent from intracellular membranes
- the metabolic precursor of steroid hormones
How is cholesterol oriented in the plasma membrane?
- parallel to the fatty acid chains of the phospholipids
- the hydroxyl group interacts with the phospholipid head group
What are the major membrane lipids?
Phopholipids 70%
Glycolipids 5%
Cholesterol 20%
