Lipids-triglycerides Flashcards
What elements are lipids composed of
C , H , O
Whats a macromolecule
A very large organic molecule
What’s a lipid
A group of substances(triglycerides, phospholipids and cholesterol) that are soluble in alcohol rather than water because they are non polar.
How are triglycerides formed?
Condensation reaction occurs between
-COOH group of the three fatty acids and three -OH groups of the glycerol .Three water molecules are produced, and three ester bonds are formed .In some cases, the same type of fatty acid may bond to each -OH group, or the fatty acids may be different.
What does a triglyceride consist of ?
Glycerol and three fatty acids
What is glycerol
a 3 carbon molecule with 3 free -OH groups
What do fatty acids consist of
A carboxyl group (-COOH) on one end attached to a hydrocarbon chain(2-20 C atoms long).
What happens when a fatty acid is dissolved in water
The carboxyl group ionises into H+ and -COO^- group
Why are fatty acids , acids?
because it can produce free H+ ions
What does it mean if a fatty acid is saturated
there are no C=C bonds in the molecule , it is saturated with hydrogen
What does it mean if a fatty acid is unsaturated
There are one or more C=C bonds in the molecule , it is unsaturated with hydrogen
What makes a fatty acid monounsaturated
Having one C=C bond
What makes a fatty acid polyunsaturated
Having more than one C=C bonds
What happens to the shape of the hydrocarbon chain if a fatty acid has one or more C=C bond
It has a kink where the double bond is . Kinks push molecules apart slightly which makes these unsaturated fatty acids more fluid.
Why is the melting point lower when there are more unsaturated fatty acids
Its lower because their double bonds make kinks which weaken intermolecular forces and reduced energy required to break them.
What’s an ester bond
Its formed between an alcohol and a carboxylic acid.
Is an ester bond a type of covalent bond
yes
Is a triglyceride saturated if it has one saturated fatty acid tails
No , it needs to have atleast two
Is a triglyceride unsaturated if it has one unsaturated fatty acid tail
No , it needs to have atleast two
How are triglycerides formed
A condensation reaction happens between the -COOH group of the three fatty acids and the three -OH groups of the glycerol.It is a condensation reaction so three water molecule and three ester bond are made. In some cases, the same type of fatty acid may bond to each -OH group, or the fatty acids may be different(draw a diagram)
what is formed when two fatty acids and glycerol react ?
A diglyceride
What is formed when one fatty acid and a glycerol react?
A monoglyceride
(Functions)How are triglycerides a good energy source
They can be broken down in respiration to generate ATP.The ester bonds a hydrolysed so the glycerol and fatty acids can be broken down into co2 and water.Respiration of a lipid produces more water than respiration of a sugar
(Functions)How are triglycerides a good energy store
They are insoluble so they can be stored without affecting water potential.1g of fat releases 2X more energy than 1g of glucose.
