Flashcards

Lipids

Tamika Demiyah CZB190 English 27 cards

Describe/ draw the structure of a triglyceride.

Cards in this deck (27)

1What are lipids?Organic molecules (in living organisms) that are insoluble in water but soluble in non-polar organic solvents
2What are the major roles of lipids in biology? (Hint. 4)Energy storage (fat)
Chemical messengers - signalling
Structural - phospholipid bilayer/ cellular compartments/ organelles
3How are fats classified? (Hint. 4)Fats & waxes
Eicosanoids
Steroids
Complex lipids
4True or false. Fats are naturally occurring carboxylic acids.True
5True or false. Fats usually have an odd number of carbon atoms and a branched carbon chain.False. Fats usually have an even no. carbons & an unbranched carbon chain
6Reference. Fat length classification.Long-chain fatty acids: C12-C26
Medium-chain fatty acids: C8-C10
Short-chain fatty acids: C4-C6
7Describe/ draw the structure of a triglyceride.Triesters of glycerol & long-chain carboxylic acids (fatty acids)
8True or false. Triglycerides are the main form of fatty acid (energy) storage in animals only.False. Triglyerides are the main form of energy in plants & animals.
9Explain why fats are solid/ semi-solid and oils are liquids at room temperature?Fats - made of saturated fatty acids - can pack closely together --> solid
Oils - made of unsaturated fatty acids - bends at double bond prevents closely packing --> liquid
10Reference. Fat melting point dependence on % of saturated & unsaturated fatty acids in the triglyceride.
11Reference. Ratios in fatty acids.
12Explain the process of triglyceride hydrolysis. Draw the reactants, intermediates & products.
13Explain the process of saponification. Draw the reactants, intermediates & products.ester bond hydrolysis (in basic solution) -> fatty acid (carboxylic acid) salts + glycerol
14Explain how soap 'cleans'.micelle formation of fatty acids trap grease in the centre
~ polar portion interact w/ water
~ non-polar portion dissolves in non-polar oil/ grease
15What happens when fatty acids are hydrogenated?Carbon-carbon double bonds - reduced to single bonds w/ hydrogen as catalyst
16What are the potential negative outcomes of fatty acid hydrogenation?Usually when oils converted to semi-solid
Partial hydrogenation cause formation of trans fatty acids that changes MP of hydrocarbon chain --> negative effects on blood cholesterol
17Reference. Complete vs. Partial hydrogenation.
18Describe the structure & function of eicosanoids.~ Straight chain polyunsaturated C20 fatty acids
~ Signalling molecules synthesised from arachidonic acid (type of eicosanoid)
19Give 2 examples of eicosanoids & their uses
20Describe the structure and function of steroids.~ fused ring system of three 6- & 5- membered rings
21Describe the structure of glycerophospholipids
22Describe the structure of Sphingolipids
23Describe the structure of glycosphingolipids
24Describe the structure of glycoglycerolipids
25Fill in the blanks. 80% of the mass of a cell membrane is _______ material: phospholipids, ______ & ______ (6-9mm think)lipid, glycolipids, cholesterol
26Describe the structure of the lipid bi-layer. How is it formed?Non-polar tails aggregate together and polar heads point towards the exterior and interior of the cell
~ held together by hydrophobic interactions
27How is membrane fluidity maintained?Unsaturated fatty acids & cholesterol prevent tight packing of fatty acid chains & preserve fluidity