Lipids (building blocks 5 and 6) Flashcards
What is a biological lipid?
biological compounds that are generally insoluble in water…
…but soluble in organic solvents, i.e. they’re hydrophobic
What are some biological functions of lipids?
Storage of energy, insulation from environment, protection, water repellent, buoyancy control
What are fatty acids made up from?
Carboxyl group and a hydrocarbon chain
What are fatty acids?
A component of other lipids, when not- it’s referred to as a free fatty acid (FFA)
Saturated fatty acids
No double bonds in the hydrocarbon chain
Unsaturated fatty acids
Contain a double bond in the chain, results in a kink- the more double bonds, the more fluid the fatty acid and lower the melting point
What are 3 arachidonic acid derivatives?
Prostaglandins, Thromboxanes, Leukotrienes
Function of Prostaglandins
Mucosal protection, renal blood flow, inflammation and fever
Function of Thromboxanes
Formation of blood clot s
Function of Leukotrienes
Smooth muscle contraction in lungs and inflammation
Triglycerides
Made up of three fatty acids, and glycerol- each of the three OH groups forms an ester bond with the carboxyl group of a fatty acid
What hydrolyses ester bonds?
Can be hydrolysed by either lipases or esterase’s
Why do fats need to be digested?
Triglycerides cannot cross cell membranes, FA and Glycerol can with the help of transporters
What happens once Fatty Acids are in the cell?
They are reconverted into TGA’s within the cell and exported into the blood as part of the Lipoprotein pathway (and or chylomicrons)
Chylomicrons
TAG’s are digested into FA and monocylglycerol components in the small intestine,
lipoproteins
particles consisted of apoliproteins and phospholipids
Enterocytes
Epithelial cells within the small intestine
Where are Chylomicrons produced
In Enterocytes
Which animal does not have brown adipose tissue
Pigs
Chylomicrons
TAGs are digested into FA and
monoacylglycerol components in the small
intestine.
* Re-constituted into TAGs within enterocytes.
* Packaged in the ER of enterocytes into
chylomicrons.
* Particles composed of phospholipids and
apolipoproteins – lipoproteins.
* Enter the lymphatic system via the lacteal
where they join lymph fluid to become chyle
fluid.
* Chyle returns to vascular system through
venous return and then supplies tissues with
TAGs.
Lipogenesis
Synthesis of fatty acids and triglycerides, excess glucose is converted to fatty acids and triglycerides for long term storage in the adipocytes
What is the process of Lipogenesis
Acetyl CoA (from glycolysis and Pyruvate).
* NADPH is required for each additional Acetyl CoA.
* Plus Glycerol (from glucose) to form TAGs.
* Happens mainly in the liver.
* Main pathway for getting rid of excess glucose.
* TAGs are exported from the liver cell as VLDL to other tissues.
Lipolysis
Breakdown of stored TAG’S to FA’S and glycerol, induced by several hormones, the free fatty acids are then transported via the blood to other organs (skeletal/ cardiac muscle and liver)
Carnitine shuffle
How fatty acids are transported into the membrane
