Lipids

Question 1

What are lipids?

Answer 1

Non-polar macromolecules. Including fats and oils.

The electrons in their outer shell are evenly distributed, making them insoluble

Question 2

What is a triglyceride?

Answer 2

A lipid, made of one glycerol and 3 fatty acids.

Consist of a caboxylic+hydrocarbon

CONDENSATION REACTION

Question 3

How do glycerol and fatty acids come together?

Answer 3

Hydroxyl groups interact, producing 3H20 and 3 ester bonds.

Question 4

What is a phospholipid?

Answer 4

A modified triglyceride containing P as well as H C O

Question 5

What are the 6 main roles of lipids?

Answer 5

1. Membrane formation
2. Hormone production
3. Waterproof layer(because fat is hydrophobic)
4. Protect internal organs(good shock absorber)
5. Energy store(very dense, yield 2x more/g than carbs)
6. Thermal insulation(bad heat conductor)

Question 6

What are saturated fats?

Answer 6

• Single bonds which pack tightly
• All carbon atoms form max number of bonds
• Solid at room temp(common in warm environments)

Question 7

What are unsaturated fats?

Answer 7

• Double bonds, causes kinks meaning it cant pack as tightly
• Makes bilayer more mobile
• Liquid at room temp(common in cooler environments)

Question 8

What are the 2 types of unsaturated fats?

Answer 8

Monounsaturated- One double bond between carbons

Polyunsaturated- More than one double bond between carbons

Question 9

What are sterols?

Answer 9

-Lipids containing 4 rings of carbon atoms

-Hydroxyl group is hydrophilic, rest is hydrophobic(similar to phospholipid in this respect)

Question 10

Where is cholesterol created?

Answer 10

In the liver and intestines

Question 11

What role does cholesterol play in cell membranes?

Answer 11

Regulates fluidity and prevents them from becoming too fluid in warm temperatures

Question 12

What does cholesterol help to make?

Answer 12

Other steroids eg,

-Vitamin D

-Hormones

-Bile

All are fat soluble, easier to pass phospholipid bilayer

Question 13

What is the test for lipids?

Answer 13

EMULSION TEST.

1. Sample is mixed with ethanol
2. Resulting sample is mixed with water, shake

Positive= white emulsion on top of solution

Negative= clear solution