Lecture 13 - Lipids Flashcards
What is a Lipid?
- Water insoluble biomolecules that are highly soluble in organic solvents
- Membrane constituents
• Fatty acids are key constituents of lipids
• The hydrophobic properties of lipids are due to the fatty acids
Fatty Acids contribute the ______________, the most biologically
significant properties, of lipids
hydrophobic properties
Fatty Acids terminate with ___________
carboxylic acid group
Derivatives of Fatty Acids serve as:
hormones, signal molecules, and intracellular messengers
State the number of double bonds and Saturated or Unsaturated:
Octadecanoic acid (stearic acid )
C18
Saturated
No double bonds
State the number of double bonds and Saturated or Unsaturated:
octadecenoic acid
Unsaturated
one double bond
State the number of double bonds and Saturated or Unsaturated:
octadecatrienoic acid
Unsaturated
three double bonds
State the number of double bonds and Saturated or Unsaturated:
octadecadienoic acid
Unsaturated
two double bonds
The ω carbon refers to:
The methyl carbon atom at the distal end of the
chain is called the ω carbon
ω–3 fatty acid has a double bond at what point
Fatty acids usually contain an ____ number of C atoms, typically
between _________.
extra: what are the most common?
even, 14 and 24
most common: 16-18
The configuration of the double
bonds in most unsaturated fatty
acids is “cis” or “trans”, why?
“cis”, trans is much harder to breakdown
Which has a lower melting point, unsaturated or saturated fatty acids of the same length?
Unsaturated fatty acids have a lower melting point than saturated
fatty acids of the same length
The melting points of saturated fatty acids increase or decrease with the chain
length?
increase
Which of the following is an essential fatty acid?
A. Stearic Acid
B. Oleic Acid
C. Linoleic Acid
D. Laurate
C. Linoleic Acid
Which of the following is a non-essential fatty acid?
A. Octadecatrienoate (Linolenate)
B. Eicosapentaenoic acid (Arachidonate)
C. Arachidate (n-Eicosanoate)
D. Linoleate (Octadecadienoate)
C. Arachidate (n-Eicosanoate)
Why are archaeon’s able to survive in such hostile environments?
Ether linkage - more resistant to hydrolysis
Branched and saturated hydrocarbons - more resistant to oxidation
A phospholipid molecule is constructed
from what 4 components?
- fatty acid: provides a hydrophobic barrier
- a backbone to which fatty acids are attached - glycerol (3-carbon alcohol; phosphoglycerides) or a sphingosine (a more complex alcohol; sphingomyelin)
- a phosphate
- an alcohol attached to phosphate
What is a key intermediate in the
biosynthesis of other
phosphoglycerides.
Phosphatidate (look at structure)
State the function:
Phosphatidylserine
Important for memory and cognition
State the function:
Phosphatidylcholine
major constituent of cell membrane and pulmonary surfactant
State the function:
Phosphatidylethanolamine
composing 25% of all phospholipids.
In human physiology, they are found particularly in nervous tissue such as the
white matter of brain
State the function:
Phosphatidylinositol
important signaling and other functional activities in eukaryotic cell
State the function:
Diphosphatidylglycerol (cardiolipin)
Important component of inner mitochondrial membrane
The following describes?
The phospholipid with the sphingosine as the backbone.
The amino group of the sphingosine backbone is linked to a fatty acid by an
amide bond
Found in animal cell membranes, especially in the membranous myelin
sheath that surrounds some nerve cell axons
Sphingomyelin
The following describes?
Sugar-containing lipids
Derived from sphingosine
Differ from sphingomyelin is the identity of the unit that is linked to the primary hydroxyl group of the sphingosine backbone
Glycolipids (recognize the structure)
The following describes?
The simplest glycolipid
Contains a single sugar residue, either glucose or galactose
important components in animal muscle and nerve cell membranes
Cerebroside (look at structure)
The following describes?
A steroid, present in eukaryotes but not in most of prokaryotes, is built
form 4 fused saturated hydrocarbon rings
Further classified as a sterol because of its C3-OH group and its branched aliphatic side chain of 8 to 10 C atoms at C-17
The most abundant steroid in animals
Cholesterol
TQ: Short chain length and unsaturated enhance fluidity of fatty acids and their derivatives? T/F
(Short chain length and unsaturated lower the melting point)
True
