Lipids

Question 1

Lipids are used as a…

Answer 1

Principal form of storing energy

Question 2

Lipids are ____ in water

Answer 2

Insoluble

Question 3

Where are lipids found?

Answer 3

Membranes

Major structural elements of biological membranes

Question 4

Fatty acids

Answer 4

Hydrocarbon derivatives
Stored form of energy
Low oxidation state

Carboxylic acid + hydrocarbon chain

Question 5

Saturated vs unsaturated

Answer 5

Saturated: single bonds

Unsaturated: double bonds

Question 6

What changes melting point (fatty acids)?

Answer 6

Increase mp:
- single bonds (saturated)
- long hydrocarbon chains

Decrease mp:
- double bonds (unsaturated)
- short hydrocarbon chains

Question 7

Solubility of fatty acids in water

Answer 7

Low solubility:
- longer fatty acid chain (non polar)
- less double bonds

High solubility:
- short chains
- more double bonds

Question 8

Triacylglycerols

Answer 8

3 fatty acids + 1 glycerol

Store energy (adipose)

Insulation

Lipases catalyze the hydrolysis of triacylglycerols

Question 9

Lipases

Answer 9

Enzymes that catalyze the hydrolysis of triacyglycerols

Releasing fatty acids for export to sites that require fuel

Question 10

What is more common in fatty acids, cis or trans double bonds?

Answer 10

Cis

Question 11

Waxes

Answer 11

Esters of long chain fatty acids and long chain alcohols

Energy stores
Water repellent
Higher mp

Question 12

Two back bones of lipids

Answer 12

Glycerol

Sphingosine

Question 13

Glycerophospholipids

Answer 13

Fatty acids eateries to two of the hydroxyl groups of glycerol

Head group (alcohol) eateries to third hydroxyl group of glycerol

Via phosphodiester bonds

Question 14

What do glycerophospholipids have many of?

Answer 14

Many head groups

Question 15

Sphingolipids

Answer 15

Sphingosine + long chain aliphatic amino alcohol + 2 hydrocarbon chains

No glycerol

Important for RED BLOOD CELLS

Question 16

Sterols

Answer 16

Four fused rings + hydroxyl group (polar head)

Cholesterol:
- membrane component
- Precursor to steroids

Question 17

Types of phospholipids

Answer 17

Glycerophospholipids

Sphingolipids

Question 18

lipid nomenclature convention

Answer 18

the chain length : number of double bonds
18:1

Question 19

where are phospholipids and sphingolipids degraded?

Answer 19

lysosomes

Question 20

PUFAs

Answer 20

polyunsaturated fatty acids

omega-3/6 fatty acids

double bond on 3rd carbon and 6th carbon

Question 21

cis vs trans fatty acids

Answer 21

Question 22

Answer 22

Question 23

polar lipids (2)

Answer 23

glycerophospholipids
sterols

Question 24

In saturated fatty acids, the carbons are linked exclusively by single bonds. Monounsaturated fatty acids have one carbon-carbon double bond and polyunsaturated fatty acids have more than one.
A. Both statements are true
B. Both statements are false
C. First statement is true and second is false
D. First statement is false and second is true

Answer 24

A

Question 25

The molecule pictured below plays a major role as an:
A. Energy source
B. Membrane component
C. Signal mechanism
D. Two of the above
E. All of the above

Answer 25

A. energy source
B. membrane componentt

?

Question 26

Answer 26

1. triacylglycerol
2. hydrophilic: glycerol polar head
3. hydrophobic: carbon non-polar tails

Question 27

Answer 27

1. 18:3 (delta 9, 12,15) OR omega-3 (w-3)
2. 22:6 (delta 4, 7, 10, 13, 16, 19) OR omega-3 (w-3)
3. 20:4 (delta 5, 8, 11, 14)

MP rank (high to low)
1.
only three double bonds (less double bonds = increase mp)
short c chain (decreases mp)

2. six double bonds (more double bonds = decrease mp)
   long c chain = increases mp
   * lowest mp
3. four double bonds
   long c chain = increase mp

Increase mp:
- single bonds (saturated)
- long hydrocarbon chains

Decrease mp:
- double bonds (unsaturated)
- short hydrocarbon chains