TOPIC 1 BIO MOLECULES- Lipids Flashcards
What are the two main types of lipids?
-Phospholipids
-Triglyceride
What is a lipid?
Biological molecules made of carbon, hydrogen and oxygen which are only soluble in organic solvents such as alcohols
What are triglycerides
lipids made up of one molecule of glycerol and 3 molecules of fatty acids joined by ester bonds formed in condensation reactions
How is the residual group normally formed for triglycerides?
from a hydrocarbon chain
Do fatty acids have a carboxyl group?
yes (COOH)
What are saturated lipids?
contain only single bonds between carbon atoms
What are unsaturated lipids?
Contain double and single bonds between carbon atoms
Where are saturated fats found?
animal fats
where are unsaturated fats found?
plant oils
how is triglycerides structure related to its properties
low mass: energy ratio- good storage molecule with a lot of energy(high calorific value)from oxidation
non polar lipids- insoluble, water potential is not affected
insoluble hydrocarbon chain- no effect on water potential and can be used for waterproofing
slow conductor of heat- thermal insulation
less dense than water- buoyancy of aquatic animals
Can the R group of a fatty acid be saturated or unsaturated
yes
Is it true that in phospholipids one of the fatty acids of a triglyceride is substituted by a phosphate-containing group
yes
are phosphate heads hydrophilic or hydrophobic ?
hydrophilic (attracts water)
a phosphate tails hydrophilic or hydrophobic?
hydrophobic (repels water)
how are phospholipids structure related to their properties
polar bilayer can be formed in aqueous environments
can form glycolipids with carbohydrates which are important on the cell surface membrane for cell recognition
What do phospholipids form as result of being in contact with water?
micelles
What is the emulsion test used for?
to test for the presence of lipids
describe the structure of phospholipids
amphipathic molecule -glycerol backbone attached to 2 hydrophobic fatty acid tails and 1 hydrophilic polar phosphate head
forms a phospholipid bilayer in water which is a component of membranes
tails can splay outwards which allow for waterproofing
what are the similarities of phospholipids and triglycerides
both have a glycerol backbone
both may be attached to a mixture of saturate, monosaturated and polyunsaturated fatty acids
both contain carbon, hydrogen and oxygen
both are formed from condensation reactions
what are the differences between phospholipids and triglycerides
phospholipids:
-2 fatty acids and 1 phosphate group attached
-hydrophilic head and hydrophobic tail
-used primarily in membrane formation
triglycerides:
-3 fatty acids attached
-entire molecule is hydrophobic
-used prinmarly as a storage molecule( oxidation releases energy)
are phospholipids and triglycerides polymers?
no they are not made from small repeating units, they are macromolecules
what is LDL
low density lipoprotein cholesterol ( bad)
What is HDL
high density lipoprotein cholesterol (good)
Which lipid produces more LDl and which one produces more HDl
staurated= more LDL
unsaturated= more HDl
