lipids Flashcards
contain
carbon, hydrogen, oxygen
2 types of lipids
triglycerides, phospholipids
Lipids are not
polymers as they are not chains of repeated units
Lipids in water
insoluble in water as they are non-polar but soluble in organic solvents
diff to carbo
more O2 in carbo
lipids have a large number of C-H bonds
triglycerides
common type of lipid
made of molecule of glycerol joined in a condensation reaction to 3 fatty acids
ester bond
molecules formed in a triglyceride formation
no different types of molecules formed in this
4-1 triglyceride & 3 molecules of water
2 types - water & triglyceride
fatty acids info
- vary in length whether C=C bond present
- R grouping in the fatty acid is varibale
- some are saturated fatty acids with no C=C
- some are unsaturated fatty acids with C=C , less hydrogen bonds
- the double bond influences the properties of the molecule (such as MP &BP)
how are the two ends of a fatty acid molecule different
one end had a carboxylic -COOH and other has CH3 methyl end
difference between mono and poly unsaturated fatty acid
mono - 1 C=C
poly - 2+ C=C
HDL
high density lipoproteins (good)
LDL
low density lipoproteins (bad)
picks up bad CHL to arteries
phospholipids
special types of fat that are the main constituent of cell membranes
one of the fatty acids found in a triglyceride is substituted by a phosphate group
how is phospholipid diff to triglyceride
P - 2 fatty acids T - 3 fatty acids
P - has a phosphate group T -doesnt
phospholipids form monolayer, tri dont
how is phospholipid similar to triglyceride
fatty acids, glycerol, ester bonds, C, H, O (P has phosphorus) insoluble in water
phosphate in water
hydrophilic (polar) which means that it will orientate itself towards water
fatty acids water
hydrophobic (non-polar) which means they will orientate itself away from water
fluid mosaic model
used to describe membrane structure
glycolipids
special types of fat that are also found in cell membranes
one of the fatty acids found in a triglyceride is substituted by a sugar or chain or sugars
glycoproteins
have sugar residues attached to their surface and always point towards the tissue fluid (extracellular fluid)
glycolipids and glycoproteins
are important in the process of recognition and how the immue system distiguishes between ‘self’ and ‘non-self’ and in cell adhesion.
lipids solubility
all lipids will disolve in organic solvents, but are insoluble in water
this is important as it means that they don’t interfere with the many reactions which go in the aqueous solution inside the cytoplasm of the cell
lipid function
energy store - lipids provide more energy per gram than carbohydrates
insulation - fats are insulators
protection - fat is packed around major organs
waterproofing - due to insolubility in water
cell membranes
how is the structure of a phospholipid linked to its main function
- hydrophilic phosphate (head) and hydrophobic fatty acid (tails) allows it to form a bilayer in membranes
- controls what goes in and out of cells as any small and lipid-soluble (non-polar) molecules can pass through this bilayer
test for lipids
emulsion test
add 2cm3 food sample
add 2cm3 ethanol, mix
add 2cm3 distilled water
pos: cloudy white emulsion
neg: retains original colour
How triglyceride structure relates to its properties
Energy storage - High ratio of carbon-hydrogen bonds to carbon-carbon bonds
Long chains of hydrogen and carbon can be broken to form ATP
Metabolic water source- high ratio of hydrogen to oxygen atoms
Insoluble- doesn’t affect water potential
Low mass
