Blake_Biochem_15_Lipids

Question 1

Define: Fatty Acids and Lipids

Answer 1

Fatty acids are hydrophobic hydrocarbon chains; are key components of lipids

Lipids are amphipathic molecules

Question 2

Phospholipid (4 components)

Answer 2

1. Fatty acid
2. Backbone (glycerol or sphingosine)
3. Phosphate
4. Alcohol

Question 3

Glycerol

Answer 3

3 carbon alcohol

Question 4

Sphingosine

Answer 4

3 carbon alchohol with an amino group and two hydroxyl groups

Question 5

fuel molecules are stored as:

Answer 5

TAGs - triacylglycerols

Question 6

C18 fatty acid no double bond:

Answer 6

octadecanoic acid

Question 7

C12 fatty acid with ONE double bond:

Answer 7

dodecenoic acid

Question 8

C18 fatty acid with two double bonds

Answer 8

octadecadienoic acid

Question 9

C12 fatty acid with three double bonds

Answer 9

dodecatrienoic acid

Question 10

Fatty acids usually contain an _____ number of C atoms, typically between __ and __

Answer 10

even, 14, 24

Question 11

Which C number is most common in biological systems?

Which conformation (cis or trans) is more common in biological systems?

Answer 11

16 and 18

cis

Question 12

What determines the properties of fatty acids?

Answer 12

length of chain and degree of saturation

Question 13

Which attributes of fatty acids will RAISE melting points?

Answer 13

More Branching
Longer Length
Saturation

Question 14

Which attributes of fatty acids will LOWER melting points?

Answer 14

Less branching
Shorter Length
De-saturation

Question 15

What are the names and C-numbers of the non-essential fatty acids?

why are they non-essential?

Answer 15

Palimate, 16; Stearate, 18

because the body produces them naturally

Question 16

What are the names, C-numbers, and Omega counts of the essential Fatty acids?

why are they essential?

Answer 16

Linoleate, 18, w-6
Linolenate, 18, w-3
Arachidonate, 20, w-6

becuase the body does not produce them, they must be gathered from the diet.

Question 17

Why can some archaea survive in extremely hot thermal vents?

Answer 17

because the ether linkage is more resistant to hydrolysis, and the branched, saturated hydrocarbons are more resistant to oxidation.

Question 18

What are the three major classes of membrane lipids?

Answer 18

• Phospholipids (includes phosphoglyceride and sphingomyelin)
• Glycolipids (eg. Cerebroside)
• Cholesterol

Question 19

What is the simplest phosphoglyceride?

In what amounts is it present in membranes?

why is it important?

Answer 19

Phosphatidate

Only in SMALL amounts.

because it is a key intermediate in the biosynthesis of other phosphoglycerides.

Question 20

How do you name a phosphoglyceride that is derived from phosphatidate?

What are the 5 examples given in class?

Answer 20

phosphatidyl+functional group

phosphatidylserine
phosphatidylcholine
phosphatidylethanolamine
phosphatidylinositol
diphosphatidylglycerol (cardiolipin)

Question 21

what is the significance of phosphatidylserine?

Answer 21

important for memory and cognition

Question 22

what is the significance of phosphatidylcholine?

Answer 22

major constituent of cell membrane and pulmonary surfactant

Question 23

what is the significance of phosphatidylethanolamine?

Answer 23

• composes 25% of all pholpholipids

- in human physiology, they are found particularly in nervous tissue such as the white matter of the brain.

Question 24

what is the significance of phosphatidylinositol?

Answer 24

important in signaling and other functional activities in the eukaryotic cell.

Question 25

what is the significance of diphosphatidylglycerol?

Answer 25

important component of the inner mitochondrial membrane

Question 26

Sphingosine is an ____ _____ that contains a ____, _______ _____ ____

Answer 26

amino alcohol

long, unsaturated hydrocarbon chain

Question 27

Sphingomyelin 3 things

Answer 27

• The phospholipid with a sphingosine backbone
• The amino group of the sphingosine backbone is linked to a fatty acid by an amide bond.
• It is found in animal cell membranes, especially in the membranous myelin sheath that surounds some nerve cell axons.

Question 28

Glycolipids are derived from what backbone?

Answer 28

sphingosine

Question 29

what is the difference between a Glycolipid and a Sphingolipid?

Answer 29

both contain the sphingosine backbone, but Glycolipids have a sugar group attached to the primary hydroxyl group

Question 30

How are glycolipids oriented in the cell membrane?

Answer 30

Always with the sugar residue on the extracellular side.

Question 31

What is the simplest glycolipid?

why is it the simplest?

what are more complex glycolipids called?

Answer 31

• Cerebroside
• contains a SINGLE sugar residue on the primary hydroxyl group.
• gangliosides - branched chain of as many as 7 sugar residues

Question 32

Cerebrosides

Answer 32

the common name for a group of glycosphingolipids called monoglycosylceramides which are important components in animal muscle and nerve cell membranes.

Question 33

Cholesterol (classification and general structure)

Answer 33

• a steriod
• present in eukaryotes but not prokaryotes
• built from 4 fused, saturated, hydrocarbon rings

cyclopentanoperhydrophenanthrene - ring system

Question 34

Why is cholesterol considered a sterol?

Answer 34

Because of its C3-OH group and its branched, aliphatic side chain of 8-10 C atoms at C-17

Question 35

What is the significance of Cholesterol?

Answer 35

• the most abundant steroid in animals
• a major component of the eukaryotic plasma membrane
  
  • essentially absent from intracellular membranes
• the metabolic precursor of steroid hormones

Question 36

How is cholesterol oriented in the plasma membrane?

Answer 36

• parallel to the fatty acid chains of the phospholipids

- the hydroxyl group interacts with the phospholipid head group

Question 37

What are the major membrane lipids?

Answer 37

Phopholipids 70%
Glycolipids 5%
Cholesterol 20%