Lipids

Question 1

What r the 2 groups of lipids

Answer 1

triglyceride and phospholipids

Question 2

Structure of a triglyceride

Answer 2

1 molecule of glycerol and 3 molecules of fatty acids
Joined together by condensation reactions by forming an ester bond. there are 3 condensation reactions so 3 ester bonds are formed

Question 3

Draw structure of triglyceride

Answer 3

On manual flashcard

Question 4

Difference between saturated and unsaturated

Answer 4

Saturated= no C=C double bonds in hydrocarbon chain

unsaturated= one or more C=C double bonds in hydrocarbon chain.

Question 5

Roles of lipids

Answer 5

• in cell membranes= the phospholipid contributes to the fluidity of the membrane and the transfer of lipid soluble substances across them .
• Source of energy= when oxidised lipids provide twice as the same mass of carbohydrates and release valuable water.
• Water proofing=lipids are insoluble to water. Both plants and insects have waxy, lipid cuticles that conserve water while mammals produce oily secretion from sebaceous glands in the skin.
• Insulation= fats are slow conductors of heat and when stored beneath the body surface it helps to retain heat. Also help with electrical insulators in the myelin sheath around nerve cells
• protection=fat is stored around the delicate organs and fats are solid around room temp

Question 6

How is the structure of triglycerides related to its functions

Answer 6

Function: energy source/storage

• high ratio of C-H bonds to C atoms in hydrocarbon tails so release more energy than a same mass of carbohydrates.
• Insoluble in water so no effect on water potential of cell so no osmotic effect

Question 7

Phospholipids structure

Answer 7

one of the fatty acids of the triglyceride is substituted by phosphate containing head.

Question 8

How is the structure of Phospholipids related to its functions

Answer 8

Function: Form cell membrane allowing movement of lipid soluble substances down concentration gradient

relation to function:

• phosphate head are hydrophilic so attracted to water so orient to aqueous environment either side of membrane.
• Fatty acid tail is hydrophobic so repelled by water. Allows to orient to interior of membrane