Lipids and triglycerides Flashcards
What are uses of lipids?
Respiration, energy storage, membranes, thermal insulation, electrical insulation and protection
How are lipids used in respiration?
They release ATP
How are lipids used for energy storage?
They form adipose tissue in animals and lipid droplets in plants
How are lipids used in membranes?
There are phospholipids
How are lipids used as thermal insulation?
They form a layer under the skin in mammals
How are lipids used as electrical insulation?
They exist on some nerve cells (myelin sheath)
How are lipids used as protection?
They protect organs, plant leaves and stems (waxy cuticle)
What are lipids?
Large, complex macromolecules categorised into triglycerides (dietary fats and oils used to make other things), phospholipids (cell membranes) and sterols (hormones and waxes, including cholesterol)
What elements are lipids made of?
Carbon, hydrogen and oxygen
Are lipids soluble?
They don’t dissolve in water as they are non-polar but will dissolve in organic solvents, such as alcohols
What are triglycerides?
An energy storage that makes membrane lipids (phospholipids) and are made of 1 glycerol and 3 fatty acids
What is glycerol?
An 3 carbon alcohol that fatty acids join onto in a triglyceride and always remains the same 3C group
What are fatty acids?
Carboxylic acids (consists of -COOH groups) with a hydrocarbon chain attached to
What do both fatty acids and glycerol contain?
-OH groups
What is a hydrocarbon chain?
A chain of carbon atoms bonded together with a variable number of hydrogen atoms bonded to either side of the carbons
What is an ester bond?
A bond formed when an organic acid joins to an alcohol by a condensing reaction and the -OH groups interact
Where does an ester bond form in a triglyceride?
Between the -OH group in the carboxyl group of the fatty acids and the -OH group on the glycerol, forming 3 water molecules which are removed
How can an ester bond be broken?
By lipase by hydrolysis
What is the difference between saturated and unsaturated hydrocarbons?
Saturated hydrocarbons have no carbon-to-carbon double bond whereas unsaturated hydrocarbons contain at least 1 carbon-to-carbon double bond
What are variations within fatty acids?
They can be essential or non-essential, saturated or unsaturated, the number of carbon atoms, the number of double bonds and some are kinkier than others as each double bond forms a kink in the fatty acid tail
What are similarities in fatty acids?
They all have -COOH at one end which is what attaches to the glycerol via the -OH, they all have -CH₃ (methyl groups) at the other end and they all have chains of carbons attached to each other with hydrogen atoms attached to each carbon
What are oils?
Triglycerides containing unsaturated fatty acids as they cannot pack together tightly so they are liquid at room temperature
Where are oils found?
In plants and are generally healthier to eat
Why are triglycerides insoluble in water?
There is a methyl group at one end of the fatty acid tail which makes it hydrophobic
