Lipids Flashcards
Why do fatty acids provide a rich source of stored chemical energy for cells?
Because they are highly reduced
What are some functions of lipids?
Storage of energy
Structure and function of cell membrane
Signalling
Example of lipids in cellular membranes
Glycerophospholipids
Sterols
Example of cellular messenger lipids
Hormones
Electron carriers
Pigments
4 most common types of membrane lipids
Fatty acids
Glycerides
Non glyceride lipids
Complex lipids
2 types of fatty acids
Saturated
Unsaturated
2 types of glycerides
Phosphoglycerides
Neutralglycerides
3 non glyceride lipids
Sphingolipids
Steroids
Wax
2 types of complex lipids
Lipoproteins
Glycolipids
2 classifications of fatty acid lipids
Storage lipids
Membrane lipids
3 type of lipids that don’t contain fatty acids
Cholesterol
Vitamins
Pigments
How do many carbons do fatty acids typically contain?
Between 4-36
Which type of fatty acids have one double bond?
Mono saturated
Which type of fatty acids typically have more than one double bond?
Polysaturated
Which type of fatty acids have no double bonds?
Saturated
Why is it called omega 3 fatty acids?
Because the double bond is at the 3rd carbon
What is the omega classification used for?
Locating the double bond
How do you read C14:0 ?
C14= 14 carbons
0= no double bonds
Most common unsaturated fatty acid
Oleic acid (9-octadecacenoic)
What does the precense of cis double bonds increase in fatty acids?
The fluidity
What kinds of fatty acids cause a bend?
The cis
Which type of fatty acids are present in our bodies?
Cis
How is the solubility in water of fatty acids?
Poor
What increases the solubility of fatty acids in water?
Increased chain length
What decreases the solubility of fatty acids?
Decreasing the number of double bonds
What is the carboxylic acid group at neutral pH?
Polar and ionized
What are saturated fatty acids at room temperature?
Solid
What are unsaturated fatty acids at room temperature?
Liquid
What are trans saturated fatty acids like and why?
Unsaturated fatty acids because the chain is straight due to the trans double bond
How are the saturated fatty acids packed?
In an orderly way
How are unsaturated cis fatty acids packed?
In an less orderly way due to the kink on the chain
Why type of fatty acids does it takes least thermal energy to disrupt?
Unsaturated fatty acids
When does solubility decrease?
When chain length increases
When does the melting point decrease?
When the chainlength decreases
When the number of double bonds increases
What happens to food when the double bond of unsaturated fatty acids are cleaved oxidatively to aldehydes and carboxylic acid
It becomes rancid
What is partial hydrogenation?
Profess that converts many of the cis double bonds in the fatty acid to single bonds and trans fatty acid bonds
Practical application of partial hydrogenation
Improve shelf life
Increase stability
Increase melting temperature
Why is it called partial hydrogenation?
Some cis bonds are not fully hydrogenated so they become trans fatty acids where some are fully hydrogenated into single bonds
What are LDL?
Low density lipoproteins
What are HDL?
High density lipoprotein
What negative effects do trans fatty acids have?
Raise the level of triaclyglycerols in the blood
Raise level of LDL (bad) cholesterol in the blood
Lower levels of HDL (good) cholesterol
Increases the body’s inflammatory response
Which conformation is most common in fatty acids?
Cis
What fatty acids are essential to human health but not produced in the body?
Unsaturated fatty acids
Which is the most common storage fat?
Triglyceride
What does triglyceride contain?
3 glycerol
3 fatty acids
Do fatty acids metabolism yield more carbon energy per carbon?
Yes because they are more reduce
Why do fatty acids carry less water per gram?
Because they are nonpolar
6 lipid droplet functions
Protection against lipotoxicity
Energy and redox homeostasis
Fatty acid channeling to mitochondria
ER and membrane homeostasis
Regulation of autophagy
Lipid mediator production
Protection against lipotoxicity
What are the properties of membrane lipids?
Amphiphatic
Hydrophobic regions
Hydrophilic regions
What do glycolipids contain as the polar end?
Sugars
What are glycerophospholipids the derivative of?
Phosphatidic acid
Which is the most simple phospholipid?
Phosphatidic
Where are structural lipid degraded?
In the lysosome
What kind of lipids are gangliosides?
Glycolipids
What happens when lipids are cut down?
They are recycled
What is lysosomal storage disorder?
When you’re missing an enzyme that cuts down lipids (gangliosides) or it is not working the lipids in the lysosome are not cut down and recycled properly causing a build-up of lipids in the lysosomes
What contributes to neurodegeneration ?
Inhibition of lysosome membrane recycling as it causes accumulation of gangliosides
What is cholesterol blades on?
Steroid nucleus
General structure of cholesterol
4 hydrophobic rings (steroid nucleus)
Polar head (OH)
Alkyl side chsin
What is a steroid nucleus?
Four fused rings
General structure of sterols ?
Steroid nucleus
Hydroxyl group (polar head) in the a-ring
Various non polar side chains
What do steroid hormones do?
Regulate gene expression
What kind of structure does bile acid have?
Sterol
Where is cholesterol vey important and why?
In the membrane
Because it.creates fluidity
Do we synthesize ass the cholesterol we need?
No we need to obtain it from food
Hare steroid hormones more polar than cholesterol?
Yes
Where do steroid hormones oxidise from?
Sterols
In lipid storage/Droplets what is form of cholesterol are present?
Cholesteryl ester
What is found in lipids droplets?
Cholesteryl ethers
Triaglucerol
What is VLDL?
Very low density lipoprotein
3 types og lipoprotein particles
HDL, LDL AND VLDL
What kind of linkage is are the two actors chains attached to glycerol with in ether lipids?
Ether linkage
What proteins compose the lipid protein?
Apoprotein
What are the functions of membranes?
It defined the boundaries of the cell
Allow import and export
Retain metabolites and ions within the cell
Signal relieving and sending
Provide compartmentalisation within the cell
Produce and transmit nerve signal
Store energy as a proton gradient
Support synthesis of ATP
Is the distribution of lipids in membranes symmetric?
No
What kind of molecules are membrane lipids?
Small amphipathic molecules
What kind of interactions are between lipids in membranes?
Noncovalent
What are micelles?
Spherical structures containing amphipathic molecules arranged with hydrophobic regions in the interior and hydrophilic head groups on the exterior
When are micelle formation favoured?
When the cross-sectional area of the head group is greater than that of the acts side chains
3 type of lipid formation
Belayer
Micelle
Vesicle (liposome)
When does vesicle formation happen?
Spontaneously when a belayer sheet folds back on itself to form a hollow sphere
What kind of movement does the fluid mosaic model allow for?
Lateral but not rotation
Is transverse diffusion of lipids slow or rapid?
Very slow
Is lateral diffusion of lipids rapid or slow?
Rapid
What are eicosanoid?
Paracrine hormones, act in the area of where they are produced
How many carbons does arachidonic acid have?
20 carbon acid
What is linoleum acid?
An essential fatty acid (we can not synthesise it)
What are sterols?
Structural lipids present in the membranes of most eukaryotic cells
What kind of lipids are cholesterol?
Sterol
What do steroid hormones regulate?
Gene expression
Can we synthesise cholesterol?
Yes (mainly in liver)
Which vitamins are hormone precursors?
A and D
What does vitamin D deficiency leads to?
Defective bone formation
Disease Rickets
What is lipolysis?
Breaking of ester bonds making triglyceride into glycerol and fatty acids
What is lipogenesis?
The formation of ester bonds making glycerol and fatty acids combine to triglyceride
How many carbons in glycerol
3
How are unsaturated fatty acids named?
Carbons are numbered from the omega (methyl) end and then they are named accordingly: “omega 3”
