Lipids Flashcards

1
Q

What are lipids?

A

Heterogeneous group of compounds

Can be extracted from tissue via nonpolar solvents

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2
Q

What is the importance of lipids?

A

15% of the human body

Source of energy

Component of membranes, vitamins, hormones, and other regulatory molecules

Important in atherosclerosis and obesity

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3
Q

How much free fatty acid exists in the body?

A

Practically none

A little is attached to albumin

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4
Q

What is a fatty acid?

A

Hydrocarbon chains of various lengths and degrees of unsaturation with carboxylic acid groups

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5
Q

How do you name saturated fatty acids?

A

Name parent hydrocarbon using number of carbons, then substitute “oic” at the end

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6
Q

How do you name mono- and polyunsaturated fats?

A

Mono = ending is -enoic

Two double bonds = dienoic

Three = trienoic

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7
Q

How are fatty acids named via the omega nomenclature?

A

Number of carbons: (Double bonds)n - (where the double bonds start)

E.g. Linoleic acid

18:2n-6

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8
Q

What are the classifications for short-, medium-, and long-chain fatty acids?

A

Short <6 carbons

Medium = 6-12

Long = 13-21

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9
Q

What are very long chain fatty acids?

A

22 or more carbons

but fatty acids that are more than 22 carbons long exist in a very small percentage in the body

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10
Q

How does chain length influence membrane fluidity?

A

Shorter chain length = More fluid

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11
Q

How does saturation influence membrane fluidity?

A

Less saturation = increases fluidity

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12
Q

What type of lipids are storage lipids?

A

Triacylglycerols

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13
Q

What is the function of triacylglycerides?

A

Provide stored energy and insulation, cushioning

Made of three fatty acid chains bound to a glycerol molecule

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14
Q

Where is the unsaturated fatty acid located on the tryglyceride molecule if there is one?

A

The second carbon

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15
Q

What are three advantages to using triglycerides as fuel?

A

Carbon atoms are more reduced

TG are unhydrated, less weight

Can also be used as insulation

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16
Q

What are three common types of membrane lipids?

A

Phospholipids

Glycolipids

Cholesterol

17
Q

How are lipid bilayers formed?

A

Energetically favorable to remove hydrophobic fatty acids from water, so at a critical concentration, lipids spontaneously form micelles, bilayers, or liposomes.

Phospholipids prefer bilayers

18
Q

What are four characteristics of membranes?

A

Non-covalent

asymmetric

fluid

electrically polarized

19
Q

What are the four components of phospholipids?

A

Fatty Acids

Platform to attach the fatty acid

A Phosphate

An Alcohol

20
Q

What is phosphatidate?

A

Simplest phospholipid

Made of 2 fatty acid hydrocarbon chains, glycerol and phosphoric acid

21
Q

What are five common alcohol moieties?

A

Serine

Ethanolamine

Choline

Glycerol

Inositol

22
Q

What are lysophospholipids?

A

Phospholipids with only one acyl group attached.

Could be either acyl group

23
Q

What are plasmalogens?

A

Potent signaling lipids that are structurally similat to phosphotidylcholine or -ethanolamine

Contains an ether-linked alkene

24
Q

What are sphingolipids?

A

Phospholipid that contains sphingosine as a backbone instead of glycerol

Includes sphingomyelins and glycosphingolipids

25
How do you differentiate sphingomyelin from other phospholipids?
The presence of an amide linkage
26
What are glycolipids?
Sugar containing lipids NOT phospholipids Derived from sphingosine
27
What is cholesterol?
Lipid based on a steroid nucleus Makes membranes less fluid