Cell metabolism II Flashcards
What are some examples of lipids?
Free fatty acids, triacylgycerolis, phospholipid, glycolipids and steroids
What is the structure of triacylglycerols?
Consists of a molecule of glycerol chemically bonded through a condensation reaction forming ester bonds to 3 fatty acids
Occurs between hydroxyl group of glycerol, and the carboxyl group of the fatty acids.
What are the properties of triglycerides?
Long hydrocarbon tails are hydrophobic, insoluble in water
What are saturated lipids?
Saturated lipids have single carbon bonds, this means that they have reached the maximum amount of hydrogen bonds. Each carbon atom is bonded to the adjacent one with a single covalent bond.
What are the properties of saturated lipids?
Saturated lipids have higher melting points ,being solid at room temperature.
What are unsaturated lipids?
Unsaturated lipids have double carbon bonds, meaning that they have the ability to bond to more hydrogen atoms, through a hydrogenation reaction.
What is the biological significance of triglycerides?
Energy storage molecules Waterproofing Thermal insulation Protection of internal organs Source of metabolic water Buoyancy
Why are triglycerides good energy storage molecules?
Hydrocarbon tail of fatty acids contain a lot of chemical energy, thus a lot of energy is released when oxidised during cellular respiration
store twice as much energy per gram
Why are triglycerides good for waterproofing?
Hydrophobic nature of lipids reduces water loss through evaporation
Why are triglycerides good insulators?
Thick layer reduces SA:V ration, reducing heat loss. Stored within adipose tissue under subcutaneous fat
What is the product of B-oxidation?
Acetyl-CoA molecules
Where does b-oxidation occur?
Mitochondria
What are the sources of fats?
The diet, de novo biosynthesis, and storage deposits in adipose
What is de novo synthesis?
Synthesis of complex molecules from simple molecules.
What are bile salts?
Salts generated by the liver and stored within the gallbladder. Secreted from the bile duct into the intestine emulsifying fats to increase surface area, assisting digestion
What vitamins does bile salts assist in the absorption of?
Vitamin A,D,E & K
What results from a bile salt deficiency?
Fat passing through the gut undigested and unabsorbed resulting in steatorrhea
Describe the mechanism of action of Orlistat?
Potent inhibitor of gastric and pancreatic lipase, behaves as a competitive inhibitor of lipase.
Prevents lipids and reduces fat absorption
What are the benefits or orlistat?
Can be used to treat obesity
What are lipoproteins?
Lipids are transported in the plasma by lipoproteins.
What is the role of chylomicrons?
Dietary fat transport
What is the role of VLDLs?
Endogenous fat transport
What is the role of IDLs?
LDL precursor
What is the source of VLDLs?
Liver