Unit 1 - lipids

Question 1

Lipids

Answer 1

biological mols composed of C/ H/ and ) atoms w a high proportion of non-polar carbon-hydrogen bonds (hydroPHOBIC = immiscible w water)

Question 2

Lipid functions

three

Answer 2

energy storage
insulation building membranes
chemical signalling

Question 3

4 families of lipids

Answer 3

Triglycerides (fats / oils)
-energy storage + insulation
Phospholipids
-makes cell membrane
Steroids
-hormone signaling
Waxes
- water resistance + protection

Question 4

Triglycerides (FATS + OILS)

Answer 4

made of glycerol and three fatty acids through esterification (dehydration synthesis )
- ester linkage
-fatty acid is saturated or unsaturated

Question 5

Saturated Fats

Answer 5

• single c-c bonds
• linear = fitting close together and making weak can der Waals forces
• r solid at room temp + often come from animal sources

Question 6

Unsaturated / polyunsaturated fats

Answer 6

• one or more double or triple bonds
• have gaps or kinks in then so they loosely fit together (form fewer London forces)
• r liquid at room temp and come from plants

Question 7

Hydrogenation

Answer 7

man-made process of adding hydrogen atoms to unsaturated fats to break double or triple bonds making the unsaturated fats saturated

ie. converts oils to semisolid like margarine

Question 8

Phospholipids

Answer 8

glycerol + two fatty acids and a phosphate group.

Question 9

Phospholipids r amphiphilic

Answer 9

meaning they have areas that r hydrophilic and hydrophobic
- head is hydrophilic (water loving)
- tails r hydrophobic (water hating)

Question 10

Cell membrane

Answer 10

there is water inside + outside cells. Therefore with regards to CM, phospholipids form a bilayer that separates two watery areas (extracellular fluid and cytoplasm)

Question 11

Molecules diffusing through cell memebrane

Answer 11

small mols like water, and non-polar mol such as O or CO2 can pass directly through lipid bilayer, But large ions and mols cannot thus make membrane protein channels to allow them to pass through

Question 12

Steroids

Answer 12

r hydrophobic mols containing four hydrocarbon rings and attached to functional groups
ie. cholesterol / estrogen / testosterone

Question 13

Cholesterol

Answer 13

v important
- it helps maintain membrane rigidity during high temps and flexibility during low temps
- production of vitamin D by the skin using sunlight

Question 14

Waxes

Answer 14

lipids made of long-chain fatty acids like alcohols or carbon rings
- hydrophobic / firm / pliable / and flexible

Question 15

Waxe = waterproof

Answer 15

Cutin-wax coats plants steams leaves and fruits acts like a barrier to infections + prevents water loss
Birds Preen - their feathers (spreading oily wax substance from glands at base of tail across feathers to make them waterproof)
Bees- beeswax honeycomb