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Lipids - Coggle Diagram
Lipids
Biological functions
Storage of energy
Insulation
Water repellant
Buoyancy(浮力) control and acoustics（聲波）
Membrane structure
Cofactors for enzymes
Vitamin K : blood clot formation
coenzyme Q: ATP synthesis in mitochondria
Signaling molecules
vitamins A and D (hormone precursors)
Pigment
Antioxidants
Vitamin E
degrade in
Lysosome
Most cells
continually
degrade
and replace their membrane
lipids
Phospholipids
Degraded by phospholipasesA - D
Each phospholipase cleaves a
specific bond.
Gangliosides
Degraded via a series of enzymatic cleavages
Dysfunction in Ganglioside Recycling
Leads to a variety of medical disorders
Failure to correctly degrade
lysosomal storage disorders
Classification
Lipids that contain
fatty acids
(complex lipids)
Membrane lipids
Glycerophospholipids(polar)
Contain
polar
head groups
and nonpolar tails (usually
attached fatty acids)
Unsaturated
fatty acids are commonly found connected to
C2
of
glycerol-3-phosphate.
Phosphatidylcholine
Archean ether(醚) lipids
Plasmalogen
Common in vertebrate heart tissue
Vinyl ether analog
Platelets-Activating Factor(PAF)
Aliphatic ether analog
Stimulates aggregation of blood platelets
Sphingolipids
backbone of sphingolipids is a long-chain amino
alcohol sphingosine.
joined to sphingosine via an
amide
linkage
abundant in
myelin
sheath that
surrounds some nerve cells
Sphingomyelin Is Structurally Similar to Phosphatidylcholine
Glycosphingolipids and
Blood Groups
determined in part by the type
of sugars located on the head group
glycosyltransferases
N-acetylgalactosamine
A blood group
no active
O antigen
galactose
B blood group
storage lipids
Triacylglycerols(nonpolar)
Fat
Efficient Fuel Storage
long-term (months) energy needs
Oils
Fatty Acids
Containing 4~36 C
Almost all natural
fatty acids have an
even number
of carbons
Saturated
No double bond
Nomenclature
systematic name
common name
delta
numbering of carbon skeleton
relationship to the
carbonyl carbon
omega
numbering of carbon skeleton
relationship to the
terminal methyl
Omega - 3 fatty acid
Include ALA, DHA, and EPA
More C; Higher Meltiong point ; lower Solubility
More Alkene ; Lower Melting point
unsaturated
commonly in
cis
configuration(
kink
)
Trans Fatty Acids
higher melting points
increases risk of
cardiovascular
disease.
pack more regularly
Wax
esters
of long-chain saturated and
unsaturated fatty acids with long-chain alcohols.
high melting points
Honeycomb
Lipids that
do not contain fatty acids
Sterols & Cholesterol
Four fused rings
Hydroxyl group
in the A - ring
Various nonpolar
side chains
（Ｄ）
The tetracycle structure of sterols is
almost planar
Steroid nucleus
Physiological Role
in the membranes most
eukaryotic
cells
fluidity and permeability
thicken the plasma membrane
no sterols in most bacteria
obtain
cholesterol
From
food
Synthesize it in the
liver
Cholesterol is transported to
tissues via
blood vessel
Cholesterol in
low-density lipoproteins
tends to
deposit
and
clog
arteries
.
Steroid Hormones
oxidized derivatives(氧化衍生物) of sterols
Have the sterol nucleus; lack the alkyl chain
more polar than cholesterol.
synthesized from cholesterol
gonads(生殖腺)
adrenal glands
Carried
In the bloodstream,usually attached to carrier proteins
Many of them are male and female
sex hormones.
Biologically Active Lipids
much smaller amounts
signaling
molecules between nearby cells
Lipid-soluble vitamins (A, D, E, and K)
Vitamin D
Synthesized from
Cholesterol
Regulates
Calcium
Metabolism
UV light
—>Cholecalciferol (Vitamin D3)
Vitamin A (Retinol)
Derived from
ß-carotene
Involved in visual pigment
Precursor(前導物) for other hormones involved in
signaling
Vitamins E
An
antioxidant
Vitamin K
A
blood clotting cofactor
Arachidonic Acid(花生四烯酸)
Derivateves as signaling lipids
prostaglandins 前列腺素(inflammation and fever)
thromboxanes血酸素 (formation of blood clots)
leukotrienes白三烯 (smooth muscle contraction in lungs)
Polyketides
a diverse family of compounds synthesized similarly to fatty acid
biosynthesis
