Chapter 2 - Lipids Flashcards
What is a lipid?
A biomolecule (molecule present in biological processes) that is soluble in nonpolar solvents.
Are lipids polymers?
No, they are not made of many similar monomer units
What is the role of lipids?
Act as an insulating layer, act as an energy store & energy source (important in living cells with high energy yield), make up biological membranes, form waxy cuticle around leaves and plants
What are triglycerides?
Includes fats and oils (formed by a condensation reaction between a fatty acid and a glycerol)
What is the bond formed between a glycerol and a fatty acid called (in triglycerides)?
An ester bond
What is similar and de-similar in each individual triglyceride?
They all have the same glycerol (an alcohol) but have a different fatty acids
What is the structure of a glycerol?
Made of three carbon atoms (down the central line), then three -OH groups attached (to the right side of each carbon; then also the remaining unattached carbons are bonded to hydrogen groups (the three left hand sides and one at the top and bottom)
What is the structure of a fatty acid?
Consists of a hydrocarbon chain (which varies in length) and a carboxylic acid containing a carboxyl (COOH) group
What is a saturated fatty acid?
One where its hydrocarbon chain has no double bonds between two carbon atoms
What is an unsaturated fatty acid?
One where there is a double bond present between two carbon atoms, this changes its shape (kinks at the point) and means they are more fluid (less solid)
What is the structure of phospholipids?
(Similar to triglycerides) One glycerol molecule, 2 fatty acids attached to a carbon each, and the third carbon of the glycerol is attached to a phosphate group
What is the structure of a triglyceride?
One glycerol molecule and three fatty acids
What is the purpose of the phospholipids structure?
It is part hydrophobic and part hydrophilic, mostly the phosphate group is attached to a nitrogen containing water soluble group, this forms a phosphate head (hydrophilic) whereas the two fatty acid tails are hydrophobic
What is the nitrogen containing soluble group that the phosphate group attaches to?
Choline
What is cholesterol?
A molecule similar to phospholipids, with hydrophobic/phylic regions, it is important in cell membranes in eukaryotic cells
