12. Lipids

Question 1

how are lipids defined ?

Answer 1

• insolubility in water
• high solubility in non polar solvents

defined by physical behaviour rather than chemical structure

Question 2

lipids are largely _____ in composition

Answer 2

hydrocarbon

Question 3

describe structure of fatty acids and formula

Answer 3

• long nonpolar hydrocarbon tail and polar carboxyl group (head)

formula = R-COOH
R=tail

Question 4

FAs differ from eachother by (3)

Answer 4

• length of tail
• degree of unsaturation
• position of double bonds

Question 5

saturated vs unsaturated FAs

Answer 5

saturated = no double bonds / packed tightly/ more rigid

unsaturated = cis double bonds causing kinks (bends) greater potential for motion / lowers melting temp

Question 6

naming for 1/2/3 double bonds

Answer 6

1- enoic
2- di enoic
3- tri enoic

Question 7

longer chain =

Answer 7

longer chain = higher melting point and less solubility in water

Question 8

relationship between melting point and double bonds

Answer 8

increase # of double bonds = decrease in melting point

Question 9

how to tell omega-3 vs omega-6 FA

Answer 9

relates to last double bond
- starting from farthest carbon to alpha and count

Question 10

trans double bonds are ___

Answer 10

naturally rare

Question 11

what is hydrogenation and what happens as a result

Answer 11

turn cis double bonds to trans

as a result of trans double bonds the melting point increases

Question 12

triacylglycerols

Answer 12

• energy storage
• insulation

neutral have no charge
- triolein

have same FAs = simple
have different FAs = mixed