2.2.6 lipids 1: triglycerides Flashcards
lipids
group of substance soluble in alcohol (not water)
- incl. triglycerides, phospholipids, glycolipids & cholesterol
macromolecule
very large, organic molecule
phospholipid
molecule consisting of glycerol, 2 fatty acids & one phosphate group
atoms in lipids
- lots of C & H
- smaller amounts of O
characteristics of lipids
- insoluble in water
- dissolve in alcohol
why are lipids insoluble in water
they are not polar so do not attract water molecules
3 most important lipids (living things)
- triglycerides
- phospholipids
- steroids
what are the 3 important lipids examples of
macromolecules
triglyceride structure
- made of glycerol & fatty acids
- many diff. types of fatty acids
describe what essential fatty acids are
the fatty acids (made within our body) that must be ingested ‘complete’
structure of glycerol
- 3 carbon atoms
- alcohol = free -OH groups
draw molecular structure of glycogen
check pg 61 of OCR textbook
structure of fatty acids
- carboxyl group (-COOH) on 1 end
- carboxyl group attached to hydrocarbon tail = only C & H atoms
how long can the fatty acid hydrocarbon tail be
2 to 20 carbons long
why is the fatty acid structure an acid
the carboxyl group ionises into H+ & -COOH- group
draw molecular structure of a (saturated) fatty acid
check pg 61 of OCR textbook
what does it mean if a fatty acid is saturated
no C=C bonds
what does it mean if a fatty acid is unsaturated
there’s a double bond between 2 of the C atoms
–> fewer H atoms bonded to molecule
what makes a fatty acid monosaturated & example
single C=C bond
- eg. oleic acid
what makes a fatty acid polysaturated & example
more than 1 C=C bond
- eg. linoleic acid
what impact does having 1+ C=C bond have on the structure of a fatty acid chain
- changes shape of hydrocarbon chain
- gives a kink where double bond is
- kinks push molecules apart slightly = more fluid
which lipids contain lots of saturated fatty acids
= animal lipids
- often solid at 20 degrees
what does a triglyceride consist of
1 glycerol bonded to 3 fatty acid chains
what happens to cause the glycerol & the fatty acids to bond
- condensation reaction occurs between -COOH of fatty acids & -OH group of glycerol
- water molecule produced
