Lipids Flashcards
Are triglycerides polar or non-polar?
Non-polar
Are triglycerides hydrophobic or hydrophilic?
Hydrophobic
What are the monomers?
Glycerol and fatty acids
What does glycerol contain?
A hydroxyl group bonded to a carbon atom
What do fatty acids contain?
Methyl group at one end of the hydrocarbon chain (R group) and a carboxyl group- ROOH
What are the 2 ways fatty acids can vary?
The length of the hydrocarbon chain (the R group)
They can be either saturated or unsaturated
What does saturated mean?
All single C-C bonds
What does unsaturated mean?
One or more double C=C bonds
What are triglycerides formed by?
Esterification
When does an ester bond form?
When an OH group and a COOH group form
How is water formed?
H from glycerol combines with an OH from the fatty acid to make water
What type of reaction forms an ester bond?
A condensation reaction
What is released for each ester bond formed?
A H20 molecule
What joins to make a triglyceride?
3 fatty acid join to one glycerol molecule
What is released for one triglyceride to form?
3 H20 molecules
Waterproofing?
Fully hydrophobic
Water molecules are repelled
Electrical insulator?
Triglycerides are uncharged— no delocalised electrons
Do not conduct electricity and no moving particles to conduct thermal electricity
Do triglycerides conduct electricity?
No- and no moving particles to conduct thermal electricity
How do triglycerides increase the speed of transmission of nerve impulses?
Triglycerides are part of the composition of the myelin sheath that surrounds nerve fibres- provides insulation- increases the speed of the transmission of nerve impulses
How are triglycerides respiratory substrates?
Oxidising hydrocarbons
Large number of C-H bonds to oxidise- releasing electrons which are used in ATP production
How are triglycerides good for buoyancy?
The low density of fat tissue increases the ability of animals to float more easily
What do phospholipids consist of?
Only 2 fatty acids bonded to a glycerol molecule
What has one of the fatty acids been replaced by?
A phosphate ion
Is the phosphate polar, non-polar, hydrophobic or hydrophilic?
Polar (hydrophilic)
Is the fatty acid polar, non-polar, hydrophobic or hydrophilic?
Non-polar (hydrophobic)
What function of phospholipids makes it form bilayers in water?
It’s amphipathic
What are phospholipids the main component of?
Cell membranes
What creates a hydrophobic core with a phospholipid bilayer?
The hydrophobic fatty acid tails
What does the phospholipid bilayer act as?
A barrier to water-soluble molecules
Test for lipids?
1) grind food sample using a pestle and mortar and add to test tube
2) add ethanol to test tube and shake (using a bung)
3) add water to the test tube
4) observe results
5) white emulsion will form if ethanol is present
