Lecture 15 - Lipids Flashcards
Fatty acids are water _______ (insoluble/soluble) biomolecules that are highly ______ (insoluble/soluble) in organic solvents
insoluble, soluble
What properties of lipids are due to fatty acids?
Hydrophobic properties
As the fatty acid tail gets longer, what happen to the solubility?
It becomes more insoluble
What are the most biologically significant properties of lipids?
the hydrophobic properties (contributed by fatty acids)
What makes up a fatty acid?
Hydrocarbon chains of various length and degrees of unsaturation that terminate with carboxylic acid group
Fatty Acids are the building blocks of what two biological membrane components?
Phospholipids and glycolipids
Many proteins can be modified. What is one way that involves fatty acids?
Covalent attach of fatty acid to the protein, allowing it to target membranes
How are fuel molecules stores?
As Triacylglycerols
Derivatives of fatty acids serve as:
Hormones Signal Molecules Intracellular messengers
Review nomenclature
Slide 6
Steps for Numbering the Carbon Atoms
Start at the carboxyl terminus Carbon 2 and 3 are also referred to alpha and beta The methyl carbon atom at the distal end of the chain is called the omega carbon
Numbering Double Bonds
Position of double bound is represented by ∆ followed by a superscript number Position can also be denoted by counting from the distal end (methyl group), with the omega carbon atom as number one
Do fatty acids typically contain an even or odd amount of C atoms and typically how many?
Even 14 and 24
What are the lengths of the most common fatty acids?
16 and 18
What is the configuration of the double bonds in most unsaturated fatty acids?
cis
What happens to a fatty acid at physiological pH?
It is ionized
Unsaturated fatty acids have a _____ melting point than saturated fatty acids of the same length
lower
What happens to the melting point of saturated fatty acids as the chain length increases?
The melting point also increases longer chain = higher melting point
Name the essential fatty acids
Omega-6: Linoleate and Arachidonate Omega-3: Linolenate
Linoleate # of C’s, # of double bonds, and systemic name
C’s = 18 Double bonds = 2 Systemic name: cis,cis-∆9,∆12 or octadecadienoate
Arachidonate # of C’s, # of double bonds, and systemic name
C’s = 20 DB’s = 4 Systemic name: all-cis ∆5,∆8,∆11,-∆14 Eicosatetraenoate
Linolenate # of C’s, # of double bonds, and systemic name
C’s = 18 DB’s = 3 Systemic name: all-cis ∆9,∆12,∆15 Octadecatrienoate
Identify this Phosphoglyceride
Phosphatidate or diacylglycerol 3-phosphate
A key intermediate in the biolsynthesis or other phosphoglycerides
*only a small amount of phosphatidate are present in membranes
Identify this structure and its function
Phosphatidylserine
Important for memory and cognition
Identify this structure and its function
Phosphatidylcholine
Major constituent of cell membrane and pulmonary surfactant
Identify this structure and its function
Phosphatidylethanolamine
Composing 25% of all phospholipids
Found in nervous tissue (white matter of the brain)
Identify this structure and its function
Phosphatidylinositol
Important for signaling and other functional activities in eukaryotic cell
Identify this structure and its function
Diphosphatidylglycerol (cardiolipin)
Important component of inner mitochondrial membrane
