Sean - Fatty Acid Catabolism Flashcards
What are lipids?
(5)
Group of chemically diverse, naturally occurring molecules
Macromolecules
Hydrophobic molecules
Compartmentalised molecules (in vivo)
Bound to hydrophilic molecules (in vivo)
What are the three main functions of lipids?
Cell structure
Energy storage
Intracellular messengers
In vivo lipids are compartmentalised, what does this mean?
They are membrane associated
In vivo lipids are bound to hydrophilic molecules, give an example of such a case.
Lipoproteins
Where are phospholipids often found?
Often found in structure
Where are glycolipids found and what is their main function?
(3)
They are lipids with a carbohydrate attached
They are used in cell signalling
They are found on the surface of cells to relay messages
What does saturated mean?
No double bonds
What does unsaturated mean?
There is at least one double bond
What does monounsaturated mean?
There is one double bond
What does polyunsaturated mean?
More than one double bond
How do you go about naming a fatty acid?
Count the number of carbons
Count the number of double bonds
Delta designates the position of the first C atom involved in the double bond
e.g. 16:1 (delta 9)
Classify unsaturated fatty acids
Cis and Trans fatty acids
What are trans fatty acids?
(4)
Synthetically produced unsaturated fatty aids
Produced by fermentation in the rumen of dairy animals
Hs are located on the opposite sides of the double bond
They pack in an orderly way to produce solid fats
What are Cis fatty acids?
(5)
Unsaturated fatty acids
Hs are on the same side of the double bond
Creates a kink or bend in the chain
Nearly all naturally occurring unsaturated fatty acids have this conformation
Do not contribute to the build up of cholesterol -> increase of LDL
Why do trans fatty acids increase risk of cardiovascular disease but not cis fatty acids?
Trans can pack in an organised fashion while cis cannot due to the ‘kink’ they produce in their carbon chain
Explain the risk associated with saturated fats and cardiovascular disease
Saturated fats lead to the increase of LDL (bad cholesterol) and increase in HDL (good cholesterol)
Give a source of saturated fat
Partially hydrogenated vegetable oils
How do mammals store fatty acids?
Triacylglycerols
Describe the structure of a triacylglycerol.
3 fatty acids linked to a glycerol (3C) by ester bonds
What is the main function of triacylglycerols?
Storage
What are the principle short term source of energy in humans?
Carbhydrates
What are the principle short term source of energy in humans?
Carbohydrates
What happens to excess glucose in the body?
It is converted into glycogen and stored in the liver
How much glycogen do humans store?
Only enough for a single day of energy
What happens to glycogen when glucose is needed?
Glycogen is broken down into glucose
What is the energy from tracylglycerols used for?
It’s used to sustain cellular activity
What are the three main sources of fatty acids?
They can be synthesised in one type of cell and can be transported to another
They can be consumed in the diet -> these are digested and degraded for energy/stored as triacylglycerols (exogenous reaction)
They can be stored as triacylglycerols in lipid droplets in adipocytes in adipose tissue (endogenous reaction)
Lipids are water insoluble but must be transported around the body, how is this done?
They are carried in blood plasma attached to proteins (lipoproteins)
These lipoproteins express signalling proteins so they can interact and coordinate with each other
What do lipoproteins consist of?
(5)
Apolipoproteins
Phospholipids
Cholesterol
Cholesteryl esters
Triacylglycerols
What are apolipoproteins?
A specific type of carrier proteins