Lipids Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Describe the test for lipids

A

The Emulsion Test:
1. Take 2cm3 of the test sample and add 5cm3 of ethanol.
2. Shake the test tube thoroughly to dissolve any liquid in the sample
3. Add 5 cm3 of water and shake gently
If present, a milky white emulsion will form as lipid droplets spread throughout the water (from the carbohydrates.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define Emulsion

A

A fine dispersion of minute droplets of one liquid in another, in which it is not soluble or miscible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Information on Lipids 5

A

-insoluble in water but soluble and can be dissolved using organic substances e.g., alcohols and acetones
- Good source of energy: provide x2 more the same mass as Carbohydrates as contains lots of carbon and hydrogen bonds.
- Waterproofing in plants and animals: waxy cuticle on leaves and sebaceous fluid on skin
-Good insulating material as poor conductor of heat
-protect soft organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How do triglycerides form?

A

Condensation reaction between 3 fatty acids and 1 glycerol molecule forming ester bonds, and releasing 3 water molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Properties of fatty acids

A
  • glycerol same but different fatty acids in lipids: different properties from composition of fatty acids tail
  • tails are hydrophobic, making them insoluble
  • carbon atom links fatty acid to glycerol
  • RCOOHH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Saturates fatty acid chains:

A
  • every Carbon atom is indeed to as many hydrogen atoms. No more can be added
    -found in animal fats
    -straight carbon chains
  • pack together to form solids at room temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Unsaturated fatty acid chains

A
  • double bonds: kinks in carbon chain
  • found in vegetable oils, nuts and fish
  • don’t pack together easily so liquids at room temperature
  • more double bonds = more kinks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Saturated fats definition

A

Fats containing high proportion of fatty acid molecules without double bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Unsaturated fats definition:

A

High proportion of fatty acids with at least one double bond.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Structure and function of triglycerides: 5

A
  • high ratio of energy storing carbon hydrogen bonds (excellent energy source.)
  • low mass to energy ratio: lots of energy stored in small mass. Beneficial to animals who need energy store without carrying extra weight.
  • insoluble - don’t effect osmosis in cells.
  • when oxidised, release water
    -thermal insulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Formation of phospholipids

A
  • a glycerol backbone, a polar hydrophilic phosphate group and hydrophobic fatty acid chains (2)
  • condensation reaction between them and forming ester bonds between glycerol and fatty acids
    -tails splay outwards: waterproofing and inwards = phospholipid bilayer in membrane.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Similarities of phospholipids and triglycerides: 3

A
  • both formed by condensation reaction with ester bonds.
  • glycerol and fatty acid, C and H and O
  • Possess hydrophobic properties
    -may be attached to unsaturated or saturated fatty acid.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Differences between phospholipids and triglycerides: 4

A
  • T = energy storage when oxidised P = membrane formation
  • P = can form bilayer
  • T= entirely hydrophobic P = part is hydrophobic and hydrophilic
  • T = glycerol and 3 fatty acids. P = glycerol, phosphate group and 2 fatty acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Are triglycerides and phospholipids polymers?

A

Macromolecules.
They are not made by a small repeating unit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly