Lipids Flashcards
describe the structure of a fatty acid (RCOOH)
variable R group- hydrocarbon chain (saturated or unsaturated)
COOH- carboxyll group
describe how a triglyceride is formed
a condensation reaction between 1 glycerol molecule and 3 fatty acids which removes 3 molecules of water forming 3 ester bonds
explain of the properties of triglycerides link to their function
-high ratio of C-H bonds to carbon atoms in hydrocarbon chain so they are used in respirationas they release more energy
-hydrophobic / non-polar fatty acids so they are insoluble in water so they have no effect on water potential of cell or can be used as waterproofing
describe the formation of a phospholipid
A condensation reaction reaction between a glycerol molecule, a phosphate group and 2 fatty acids forming an ester bond between the glycerol molecule and 2 fatty acid chains
describe how the properties of phospholipids relate to their function
they form a bilayer in the cell membrane allowing for diffusion of lipid soluble or very small substances and restrict the movement of larger molecules and water soluble substances
-phosphate heads are hydrophilic and so attract water
-fatty acid tails are hydrophobic so repell the water
describe the test for lipids
1, add ethanol, shake then add water
2, positive test is a milky emulsion
What is a saturated fatty acid?
They dont contain any double bonds between their carbon atoms
What is an unsaturated fatty acid?
THey contaain a carbon-carbon double bond, meaning they contain fewer hydrogen atoms
What are lipids?
they are not polymers, they contain hydrogen and carbon atoms. Lipids are a source of energy that help to insulate organisms and act as waterproofing
What bond is formed in triglycerides?
ester bond formed between each of the three OH groupson the glycerol and OH group on each fatty acid chain
what bond is formed in phospholipids?
ester bond between two OH groups n the glycerol and OH group of each fatty acid chain.
Describe the role of micelles in the absorption of fats into the cells lining the ileum.
Micelles include bile salts and fatty acids which make the fatty acids soluble in water
For lipids to carry fatty acids to the lining of the ileum, maintaining a higher concentration of fatty acids to the lining of the ileum for the fatty acids to be absorbed by diffusion
Expalin the arrangement of phospholipids in a cell surface membrane.
It forms a bilayer, with hyrophillic phosphate heads that are attracted to water, hydrophobic tails that face way from the water
