Lipids

Question 2

Characteristics of lipids

Answer 2

Lipids are a large groups of organic compounds made up of C,H,O
They are found in ever type of plant & animal cell
Are polyester formed by condensation reactions which forms of 1 glycerol and 3 fatty acids

Question 3

Fats and lipids are

Answer 3

Chemically similar but

Question 4

Fats

Answer 4

Solid at room temperature
From animal sources

Question 5

Lipids

Answer 5

Liquid at room temperature
From plant sources

Question 6

Functions of lipids

Answer 6

In cell membrane
In hormones
Mechanical protection
Thermal insulation
Energy storage molecule
Electrical insulation of nerves
Waterproof & buoyancy

Question 7

Triglycerides

Answer 7

3 fatty acids and glycerol forms triglyceride

Answer 8

The OH groups of glycerol & the carboxylic acid (-COOH) group of each fatty acid are linked by an ester bond formed by condensation reaction

Question 9

Condensation to from triglycerides

Answer 9

3 fatty acid + glycerol produces triglyceride + 3 water

Question 10

Hydrolysis to break ester bonds

Answer 10

triglyceride + 3 water produces 3 fatty acid + glycerol

Question 11

Fatty acid:

Answer 11

Saturated fatty acid
Unsaturated fatty acid

Question 12

Fatty acid classification:

Answer 12

Saturated fatty acid: jam-packed with hydrogen
The structure has the maximum number of hydrogens
Unsaturated fatty acid: missing hydrogens
There is at least 1 double bond and fewer hydrogens

Question 13

Saturated fatty acids in phospholipids

Answer 13

Saturated fatty acid chains lack double bonds, resulting in phospholipids with a straight structure that favors tight packing

Question 14

Unsaturated fatty acids in phospholipids

Answer 14

Unsaturated fatty acids have one or more double bonds that introduce kinks in the phospholipids reducing tightness of packing

Question 15

Saturated fatty acids

Answer 15

Have only single bonds
These fatty acids form straight chains
Have high melting point
Solids at room temperature

Question 16

Unsaturated fatty acids

Answer 16

Have at least one double bond between atoms in the hydrocarbon chain
These fatty acids form bent chains
Have low melting points
Liquid at room temperature

Question 17

Cholesterol

Answer 17

Strongly hydrophobic & they take
refuge between the tails of phospholipids in membrane.
Their presence in the bilayer has two effects:
1. It slows down the lateral movement
of individual phospholipid molecules
making the bilayer more stable
2. It prevents the movement of certain subsea through bilayer ensuring the membrane transport occurs through the correct protein channels