Lipids

Question 1

Lipids : elements, monomer, function

Answer 1

CHO, glycerol and fatty acids, provides energy, cell membranes, hormones

Question 2

Triglyceride functions

Answer 2

• Energy storage in animals and plants due to long fatty acid chains which contain ester bonds that release chemical energy
• Protection packing around vital organs
• Thermal insulation - reduces energy loss
• electrical insulation around neurons help speed up conduction of actio potentials
• Helps buoyancy in aquatic mammals
• source of water - when fat is being made Esther binds are made so water is released
  E.g. used for survival for camels (in humps)
• absorption of fat soluble vitamins ADEK

Question 3

Why are triglycerides a better energy storage molecule than carbohydrates?

Answer 3

• they provide more energy than carbohydrates due to the length so they release more ATP

Question 4

What is a macromolecule?

Answer 4

A large complex molecule
large molecular mass
can be made up of similar or different molecules bonded together

Question 5

What does saturated and unsaturated mean?

Answer 5

Saturated means little or carbon carbon double bonds therefore more H
Unsaturated means has double bonds

Question 6

Why do camels store fat?

Answer 6

When fat is condensed, Ester bonds are made therefore water is released. This is used to survive in dry conditions.

Question 7

Are lipids polar or nonpolar?

Answer 7

Nonpolar so they don’t dissolve in water, but they do dissolve in ethanol

Question 8

How do you test for lipids?

Answer 8

Add ethanol into the mixture for the lipids to be dissolved in the ethanol then water for it to separate a positive test can be indicated through a cloudy white emulsion forming on top

Question 9

What are lipids: polymers or macromolecules? And why

Answer 9

Macromolecules they are made of different molecules bonded together

Question 10

Triglyceride

Answer 10

Glycerol attached with Ester bonds to 3 fatty acid chains

Question 11

What is the condensation of lipids also known as?

Answer 11

Esterification

Question 12

Triglyceride sources

Answer 12

• Lipids from animals (butter lard meat) are saturated.
  They are solid at room temperature
• Lipids from plants (oil nuts seeds) are unsaturated. contain double bonds so the chain can be kinked. They are liquid at room temperature

Question 13

Triglyceride function

Answer 13

• Energy storage in animals and plants long change provide more energy than carbohydrates so release more ATP
• protection packing around vital organs
• electrical insulation around neurons help speed up conduction of action potentials
• Thermal insulation helps reduce thermal energy loss by radiation
• aids buoyancy in aquatic animals
• source of water for animals e.g. camels
• aids absorbency of fatsoluble vitaminsADEK

Question 14

Phospholipids

Answer 14

Hydrophilic Phosphate head attached to glycerol and two hydrophobic fatty acids tails

Question 15

Phospholipid functions

Answer 15

Component in cell membranes control what goes in and out of the cell by acting as a barrier to polar (water soluble) molecules

Question 16

Suggest two medical conditions that may be associated with increased blood cholesterol levels

Answer 16

Heart attacks/plague/ strokes

Question 17

Cholesterol structure

Answer 17

Hydrocarbon rings attached to hydrocarbon tail and a hydroxyl group

Question 18

Cholesterol function

Answer 18

• Strengthens the cell membrane by interacting with the phospholipid bilayer
• cholesterol has a small size and flattened.
• The shape allows cholesterol to fit in between the phospholipid molecules in the membrane.
• They blinded to the hydrophobic of the phosphate lipids causing them to pack more easily together this helps make the membrane less fluid and more rigid

Question 19

Give two reasons why triglycerides are used as energy storage molecules

Answer 19

They are insoluble and contain lots of chemical energy in the long fatty acid chains

Question 20

Explain how the structure of phospholipids make them suited to their function

Answer 20

PhosphoLipid heads are hydrophilic and their tails are hydrophobic. so they form a double layer (the bilayer of the cell membranes) with their heads facing outwards towards the water on either side. The centre of the bilayer is the hydrophobic so water soluble substances can’t easily pass through.

Question 21

Why might PH fall During the hydrolysis of lipids

Answer 21

Fatty acids are released