Chapter 5 Lipid Structure And Function

Question 1

What is an amphipathic molecule

Answer 1

Has both hydrophobic and hydrophilic regions

Question 2

What elements make up the phospholipid head and tail and what type of bond links them?

Answer 2

The phospholipid head is made from alcohol and a phosphate

The phospholipid tail is made from hydrophobic fatty acids linked by phosphodiester linkages

Question 3

What makes up the backbone of phosphoglycerides and glycerol phospholipids?

Answer 3

Glycerol

Question 4

What makes up the backbone of sphingolipids

Answer 4

Sphingosine

Question 5

What is the difference between a saturated fatty acid and unsaturated fatty acid?

Answer 5

Saturated fatty acids contain all single bonds no pi bonds and are more rigid and structure and are solid at room temperature

Unsaturated fatty acids contain one or more double bonds cannot stack because of their kinks and are liquids at room temperature

Question 6

What type of backbone make up glycerol phospholipid/phosphoglycerides? What bonds link this phospholipid together?

Answer 6

Glycerol backbone

Linked to two fatty acids via ester linkage

Also linked to the highly polar head group via phosphodiester linkage

Question 7

What are the four major sub classes of sphingolipids? And how are they classified?

Answer 7

Classified by their head group
1. Sphingomyelins 
-Phosphatidylcholine or phosphatidyl ethanolamine head group
2. Ceramide
-single hydrogen head group 
3.Glycosphingolipids
-sugar head groups 
4.Ganglioside 
-One or more Nacetylneuraminic acid NANA/sialis acid and oligosaccharides


Question 8

Where are Sphingophospholipids found and what did they do?

Answer 8

They are found in the plasma membrane of the cell and they produce myelin which insulates axons

Myelin (Oligodendrocytes and Schwann cells)

Question 9

Where are Glycosphingolipids found?

Answer 9

Glycosphingolipid’s are found on the outer surface of the plasma membrane they are also known as neutral for glycolipids because they have no net charge at physiological pH.

Question 10

What charge do gangliosides have and what role do they play in the cell?

Answer 10

Negative charge. They play a role in cell interaction recognition and signal transduction

Question 11

What is a wax?

Answer 11

Masters of long chain fatty acids with long chain alcohols. They function as protection and prevent excessive evaporation and protection from parasites

Question 12

What are three important categories of signaling lipids?

Answer 12

Steroids, prostaglandins, fat soluble vitamins

Question 13

What are terpenes?

Answer 13

Metabolic precursor of steroids and other signaling molecules. Built from isoprene moieties. 

Classified based on the number of isoprene units

Monoterpene:2
Sesquiterpene:3
Diterpene:4
Triterterpene:6 
Tetratrtpene:8

Question 14

What is the structure of a steroid what are they derived from?

Answer 14

Made up of three cyclohexane rings and one cyclopentane ring. As well as functional groups. Derived from Terpenes.

Question 15

What determines the functionality of a steroid?

Answer 15

Oxidation status of the rings that make up the steroid as well as functional groups

Question 16

What is a cholesterol?

Answer 16

Steroid

Amphipathic molecules that is a major component to the fluidity of the phospholipid by layer. Serves as a precursor for steroid hormones bile acids in vitamin D

Question 17

Prostaglandins

Answer 17

Act as paracrine autocrine signaling molecules that regulate the synthesis of cAMP. Downstream effects include effects on smooth muscle function influence over sleep wake cycle and elevation of body temperature

Question 18

Water soluble vitamins

Answer 18

DAKE

Question 19

Vitamin A

Answer 19

Aka carotene. Important for vision, growth, development immune function.

Retinal/Retinol

Question 20

Vitamin D

Answer 20

Formed through UV light driven reaction on the skin. Converted to calcitriol which promotes bone production.

Question 21

Vitamin E

Answer 21

Tocopherols and tocotrienols (hydrophobic)

Biological antioxidants. Reacts with free radicals and destroys them

Question 22

Vitamin K

Answer 22

Group of compounds including K1 and K2.

Vital to posttranslational modifications that forms prothrombin that assists with clotting factors.

Introduces calcium binding sites on calcium dependent proteins.

Question 23

Triacylglycerides

Answer 23

Lipids used for energy storage.

Yield twice the amount of energy because the carbons are more reduced than other sugars.

Energy and insulation

Question 24

What is the structure of triacylglycerols?

Answer 24

Three fatty acids bonded through ester linkages to glycerol.

Nonpolar and hydrophobic

Question 25

Saponification

Answer 25

Ester hydrolysis of triacylglycerols using a strong base.

Breakdown of triacylglycerols using a strong base.

Question 26

Surfactant

Answer 26

Lowers the surface tension (serving as a detergent or emulsifier)

Question 27

Micelles

Answer 27

Tiny aggregates of soap.

Heads hydrophilic tails hydrophobic.

Dissolves water soluble and water insoluble messes