"Lipids" 6th Week - BIOCHEMISTRY (1styr-2ndsem-Midterms)

**Lipids**

* Are a heterogenous group of compounds including: fats, oils, steroids, waxes, and related compound
* Are transported in the blood combined with proteins in lipoprotein particles

**Common properties of lipids**

a. Relatively insoluble in water

b. Soluble in nonpolar solvents such as ether and chloroform

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**Simple lipids, Complex lipids, and Derived lipids**

What are the types of lipids?

**Simple lipids**

* Fats
* Waxes

**Complex lipids**

Are esters of fatty acids which always contain:

* An alcohol
* One or more fatty acids
* Other groups

**Ester**

An any class of organic compounds that react with water to produce alcohols and organic or inorganic acids

**Phospholipids, Glycolipids, and other Complex lipids**

What are the 3 types of Complex lipids?

**Derived lipids**

* Are formed from the hydrolysis of both simple and complex lipids


* May act as precursor lipids in the formation of simple and complex lipids


* Include fatty acids, glycerol, steroids, other alcohols, fatty aldehydes, ketone bodies, hydrocarbons, lipid-soluble vitamins and micronutrients, and hormones

**Fats**

Are important dietary constituents

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Contains:

* Essential fatty acids
* Fats-soluble vitamins (e.g., vit A/D/E/K)
* Other lipophilic micronutrients

**1 gram carbohydrate**

= 4 calories

**1 gram proterin**

= 4 calories

**1 gram fat**

9 calories

**Fats**

* Stored in adipose tissue in the subcutaneous tissue and around certain organs

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* also serve as thermal insulator

**Waxes**

* Are esters of fatty acids with higher molecular weight monohydric alcohols

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* consist of long-chain fatty acid linked through an ester oxygen to a long-chain alcohol

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* completely water-insoluble and generally solid at biological temperatures

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* function as water repellants on the leaves of some plants, on feathers, and on the cuticles of certain insects

**Wax production**

Associated with the sebaceous glands of the skin

**Wax esters**

Composition of human sebum

**Complex lipids**

* Phospholipds
* Glycolipids
* other complex lipids

**Phospholipids**

Contain phosphoric residue

**Choline**

Phospholipid that have nitrogen-containing bases

**Glycerophospholipids**

Phospholipids that contain alcohol as glycerol

**Sphingophospholipids**

phospholipids that contain amino group as sphingosine

**Glycolipids**

Glycosphingolipids

* contain a fatty acid, sphingosine, and carbohydrate

**Complex lipids**

* Sulfolipids
* Amino lipids
* Liporoteins

**Neutral lipids**

These are uncharged lipids

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* acylglycerols (glycerides)
* cholesterol
* cholesteryl esters

**Derived lipids**

* Occur in the body as 90% esters and unesterified form

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* are also structural components of membrane lipids such as phospholipids

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* are also precursors of the hormone-like prostoglandins

**Fatty acid esters**

* TAG
* cholesteryl esters
* phospholipds

**Fatty acid unesterified**

Free fatty acids

**TAGs**

* Esterified FAs stored in white adipose tissue

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* serve as the major energy reserve of the body

**Alterations in fatty acid metabolism**

Are associated with obesity and diabetes

**Tissues**

**liver**

**musles**

Areas where FAs provide energy

**Liver**

Area where FAs provide the substrate for ketone body synthesis

**3 systems in naming fatty acids**

* Delta nomenclature
* Omega nomenclature
* Common anmes

**Delta nomenclature**

Identify 3 things:

number of carbons in fatty acid

number of double bonds

number of carbons are counted from the carboxylic acid end to the first carbon with double bonds

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use the delta symbol

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applies to naming unsaturated fatty acids

**Omega nomenclature**

Identify 3 things:

number of carbons in the fatty acid

number of double bonds

number of carbons are counted from the methyl end instead of the carboxylic acid end

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use the omega symbol (w) or for (n) for unsaturated FAs

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applies to naming unsaturated fatty acids

**Eicosapentaenoic Acid (EPA)**

De

Stearic Acid (Octadecanoic Acid)

Omega 18:0

Arachidic acid

Omega Name: 20:0

Lignoceric acid

Omega Name: 24:0

Oleic acid

Omega Name 18:1 (n-9)

Linoleic acid

Omega Name: 8:2 (n-6)

Alpha-linoleic acid

Omega Name: 18:3 (n-3)

Unsaturated acids

End in -enoic

ex: octadecenoic acid (oleic acid, C18)

Saturated acids

End in -anoic ex: octanoic acid (C8)

Saturated fatty acids

Butyric acid; caproic acid; caprylic acid

Butyric acid

Butanoic acid; 4:0

CAPROIC acid

Hexanoic acid; 6:0

Caprylic acid

Octanoic acid 8:0

False

**T/F**: Proteins are composed of heterogenous biomolecules

False

**T/F**: Carbohydrates are composed of heterogenous biomolecules

**Lipids**

A family of structurally diverse compounds whose similarity is only their water-solubility / immiscibility.

Fatty Acids

Simple, linear carboxylic acids

Saturated fatty acids

Contains single bonds only

Good Stacking

Solids at room temp

Have relatively high melting points

Unsaturated Fatty Acids

Contains at least one double bond

Less stacking because of kinks

Have relatively low melting points

Short-Chain FA

Composed of 2 to 6 carbons

Medium-Chain FA

Composed of 8 to 14 carbons

Long-Chain FA

Composed of at least 16 carbons

Very Long Chain FA

Composed of at least 22 carbons

Caproic Acid

Name of 6-carbon saturated fatty acid

Caprylic Acid

Name of 8-carbon saturated fatty acid

Capric Acid

Name of 10-carbon saturated fatty acid

Lauric Acid

Name of 12-carbon saturated fatty acid

Myristic Acid

Name of 14-carbon saturated fatty acid

Palmitic Acid

Name of 16-carbon saturated fatty acid

Stearic Acid

Name of 18-carbon saturated fatty acid

Arachidic Acid

Name of 20-carbon saturated fatty acid

Behenic Acid

Name of 22-carbon saturated fatty acid

Lignoceric Acid

Name of 24-carbon saturated fatty acid

a-Linolenic acid

Cervonic acid (docosahexaenoic acid) - DHA

Timnodonic acid (eicosapentaenoic acid)

Which of the following are examples of **ω-3** fatty acids?

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a-Linolenic acid

Arachidonic acid

Cervonic acid (docosahexaenoic acid) - DHA

Elaidic acid

Linoleic acid

Oleic acid

Timnodonic acid (eicosapentaenoic acid)

Arachidonic acid

Linoleic acid

Which of the following are examples of **ω-6** fatty acids?

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a-Linolenic acid

Arachidonic acid

Cervonic acid (docosahexaenoic acid) - DHA

Elaidic acid

Linoleic acid

Oleic acid

Timnodonic acid (eicosapentaenoic acid)

Elaidic acid

Oleic acid

Which of the following are examples of **ω-9** fatty acids?

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a-Linolenic acid

Arachidonic acid

Cervonic acid (docosahexaenoic acid) - DHA

Elaidic acid

Linoleic acid

Oleic acid

Timnodonic acid (eicosapentaenoic acid)

1 glycerol + 3 Fatty Acid

Structure of triglycerides

Storage lipids

Function of triglycerides

1 glycerol + 2 FA + 1 phosphate with alcohol as head group

Structure of glycerophospholipids / phospholipids

Membrane lipids

Function of glycerophospholipids / phospholipids

**None**

Head of Phosphatidic Acid

**Choline**

Head of Phosphatidylcholine (PC)

**Serine**

Head of Phosphatidylserine (PS)

**Ethanolamine**

Head of Phosphatidylethanolamine (PE)

**Inositol**

Head of Phosphatidylinositol (PI)

**Sphingosine + 1 FA + monosaccharide / oligosaccharide**

Structure of sphingolipids

**Sphingosine + 1 FA + phosphate + alcohol**

Structure of glycosphingolipids

**Saponification**

A reaction of fatty acids where a triglyceride and a strong base is mixed together to form a fatty acid salt or soap

**Rancidification**

A reaction of fatty acids where there is a complete or incomplete autooxidation of a fatty acid.

**Hydrogenation**

A reaction of fatty acids used to prolong the shelf life of unsaturated fatty acids,

**None**

Head of ceramide

**Glu / Gal**

Head of cerebroside

**Oligosaccharide**

Head of globoside

**Polysaccharide (with sialic acid)**

Head of ganglioside

**Phosphate & Choline**

Head of sphingomyelin

**Waxes**

Pliable, water-repelling substances used for repelling water and protecting surfaces

**I and IV**

Which are unsaturated fatty acids?

I. Arachidonic acid

II. Caproic acid

III. Palmitic acid

IV. Linoleic acid

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A. I and II

B. II and III

C. I and IV

D. IV only

**None of the choices**

In which of the following properties are unsaturated fatty acids greater than saturated fatty acids?

A. Melting point

B. Van der Waals forces

C. Compactness

D. None of the choices

**Vitamin A**

Deficiency of this fat-soluble vitamin may lead to night blindness and xerophthalmia

A. Vitamin A

B. Vitamin D

C. Vitamin E

D. Vitamin K

**HDL**

Which of the following has the capability to reduce plasma cholesterol?

A. VLDL

B. chylomicrons

C. LDL

D. HDL

**Acrolein Test**

Which of the following tests is used to test for glycerol?

a. Acrolein Test

b. Ammonium Molydate Test

c. Lieberman Burchard Test

d. Osmic acid Test

e. Salkowski Test

**Heating the sample**

Reagent used in Acrolein Test

**Acid/burnt odor of acrolein (propenal)**

Visible positive result of Acrolein Test

**Ammonium Molydate Test**

Which of the following tests is used to test for phosphate?

a. Acrolein Test

b. Ammonium Molydate Test

c. Lieberman Burchard Test

d. Osmic acid Test

e. Salkowski Test

**Ammonium molybdate**

Reagent used in Ammonium Molybdate Test

**Yellow ppt**

Visible positive result of Ammonium Molybdate Test