1.5 Lipids Flashcards
What elements do lipids contain?
Carbon, hydrogen, oxygen
Are lipids soluble or insoluble?
Insoluble in water and soluble in organic solvents
What are the two groups of lipids?
Triglycerides and phospholipids
What are the roles of lipids?
- source of energy - when oxidised, lipids provide more than twice the energy as the same mass of carbohydrates
- water proofing - lipids are insoluble
- insulation - fats are slow conductors of heat and they help to retain body heat
- protection - fat is often stored around delicate (脆弱的) organs
How are triglycerides formed?
Condensation of one molecule of glycerol and three molecules of fatty acid.
What will be formed when condensation reaction happens between glycerol and a fatty acid?
An ester bond
Is the R-group of a fatty acid saturated or unsaturated?
Saturated or unsaturated
What are phospholipids made of?
Condensation of one molecule of glycerol, one molecule of phosphate and two molecules of fatty acids.
Is the phosphate molecule hydrophilic or hydrophobic?
Hydrophilic (attracts water)
Are the fatty acids molecules hydrophilic or hydrophobic?
Hydrophobic (repels water)
Are phospholipids polar or non-polar?
Polar
What will phospholipids form in an aqueous solution? Where?
Bilayer, within cell-surface membrane.
What will be formed between the inside and outside of a cell?
A hydrophobic barrier
What does the hydrophilic phosphate ‘head’ of phospholipids help to?
To hold at the surface of the cell-surface membrane.
How does phospholipid form glycolipids?
By combining with carbohydrates within the cell-surface membrane.
