[Unit 1.3] Lipids

Question 1

compare triglyceride to phospholipids

Answer 1

phospholipids:
2 fatty acids
phosphate group
polar
hydrophilic head
soluble in water

triglycerides:
3 fatty acids
no phosphate group
non polar
hydrophobic
soluble in lipids

Question 2

phospholipid structure

Answer 2

polar head
-hydrophilic
-glycerol&phosphate

non polar tails
-hydrophobic
-fatty acid

Question 3

Phospholipid chemical structure

Answer 3

c-o-c=o ester bond

o
|
o-p=o
|
o

Question 4

how does the structure of triglycerides relate to their properties

Answer 4

they have a high ratio of energy storing carbon-hydrogen bonds to carbon atoms. This means they’re a good source of energy

They have a low mass to energy ratio. This means lots of energy can be stored in a small space.

They are insoluble in water (non-polar). This means they dont affect the water potential of the cell.

Question 5

difference between cis and trans fats

Answer 5

cis - hydrogens are on the same side around the double bond

trans - hydrogens are on opposite sides around the double bond.

Question 6

Why are unsaturated fats liquid at room temperature?

Answer 6

they “kink” at the double bonds. Thus, they dont tessellate as easily so structure is lost.

Question 7

why are saturated fats solid

Answer 7

they are long straight chains which can be structured neatly (tessellated).

Question 8

what are unsaturated lipids

Answer 8

(oils) fatty acids have double bonds BETWEEN CARBON BONDS in the hydrocarbon tail

Question 9

What are saturated lipids?

Answer 9

(fats) fatty acids where each carbon atom in the hydrocarbon chain has 4 other atoms bonded to it

Question 10

triglyceride chemical structure

Answer 10

3 fatty acids and a glycerol
Ester bond is C-O-C=O

(+3H2O)

Question 11

fatty acid chemical structure

Answer 11

HO-C=0
(hydrocarbon chain off carbon)

reacts with glycerol through condensation reaction

Question 12

chemical structure of glycerol

Answer 12

(alcohol (-OH functional group)) check with image

Question 13

what is a lipid made of

Answer 13

3x fatty acids, 1x glycerol

Question 14

State some uses of lipids

Answer 14

protects vital organs

phospholipids - cell membranes

waterproofing (insects and plants)

myelin sheath around nerve cells

Question 15

Test for lipids

Answer 15

add ethanol, shake, add water, shake. a white EMULSION will form (clear–>white emulsion)