Lipids Flashcards
What are different forms of lipids?
-triglycerides
-phospholipids
-steroids
-waxes
-fat- solid at room temp
-oil- liquid at room temp
Explain triglycerides
-composed of glycerol and fatty acid
-formed by esterification- condensation reaction between glycerol and 3 fatty acids
-excellent energy store- release more energy per unit mass than carbs
Explain the structure of Glycerol
C3H8O3
-form of alcohol
-3 hydroxyl groups ( -OH groups)
-no varient in the glycerol of all fats
Explain the structure of fatty acids
-considerable variation- length of hydrocarbon chain/ presence of double bonds
-CH3- methyl group
-(CH2)n- hydrocarbon chain
-COOH- carboxyl group (carboxylic acid)
- known as R-COOH
have different R groups- differ in the no. of C atoms and if they contain unsaturated (double) or saturated (single) bonds
Explain the structure of saturated fatty acids
-eg butter, lard- BAD FAT
-contain the max no. of H atoms
-all carbons are joined by single bonds- no double or other functional groups
-form long, straight hydrocarbon chains
-solid- room temp
-carbons are saturated- each attracted to 2 Hydrogen atoms
-characteristics of animals
Explain the structure of unsaturated fatty acids
-GOOD FAT
-at least on C+C double bond (not all spaces taken by Hydrogen bonds)
-liquid- room temp
-unsaturated nature- kinks in straight chains- when in lipid molecule, kinks don’t pack close together- more fluid structure
-characteristics of cold blooded animals and plants- olive oil and linseed oil
-MONOUNSATURATED FATTY ACID- ONE C=C DOUBLE BOND
-POLYUNSATURATED FATTY ACID- MORE THAN ONE C=C DOUBLE BOND
Explain estrification
-Condensation Reaction between glycerol and 3 fatty acids
-glycerol combines with 1,2 or 3 fatty acids- glyceride
-Condensation Reaction- removal of water- forms an ester bond
TRIglyceride- glycerol with 3 fatty acids
-reverse can occur- requires 3 water molecules-
Hydrolysis of a Triglyceride, eg lipid digestion
Define the term ‘Unsaturated’
Contains at least one C=C double bond
Explain Phospholipids
-main component of cell membranes-consist of glycerol and 2 fatty acids- third OH group combines with phosphoric acid- polar phosphate group
Describe how the structure of a phospholipid differs from a triglyceride
A g=triglyceride contains 3 fatty acid tails, whereas a phospholipid has 2 fatty acid tails and the third is replaced with a polar phosphate group
Name the type of reactions that occur during the breakdown and synthesis of triglycerides
-Synthesis- Condensation Reaction/ Esterification
-Breakdown- Hydrolysis
Explain the structure of phospholipids
-consists of a phosphate group as the head, and a double fatty acid tail
-the polar head is strongly attracted to water (hydrophilic)- phosphate group has a negative charge and is soluble in water
-the non-polar tail- made of hydrocarbon chains- repelled by water (hydrophobic)- insoluble in water- orientate themselves in positions- away from the watery medium
How do phospholipids form cell membranes
-The Bipolar nature of these phospholipids allow the molecules to form bilayers that form a major component of cell membranes
What happens when phospholipids are mixed with water?
-The phospholipid bilayer form droplet spheres called MICELLE
-The hydrophilic heads are facing the water and the hydrophobic tails are facing each other
Explain Steriods
-Made of large amounts of Carbon atoms, creating a complex ring shape
-example- cholesterol- molecule with a hydrocarbon chain and 3 Carbon based chains
-found in cell membranes- hydrophobic- found among the hydrocarbon chains of the phospholipid bilayer- function- stabilise membrane
Steriod hormones, eg testosterone, oestrogen and progesterone are synthesised from cholesterol
