3. Lipids

lipids

A heterogeneous group of mostly hydrophobic or amphiphatic biomolecules that includes fats, oils, waxes, phospholipids, and steroids

oils, waxes, steroids, fats

Lipids is a heterogeneous group that is composed of?

contain large nonpolar hydrocarbon regions

Why are lipid insoluble in water?

nonpolar solvents like ether, chloroform

What solvents dissolve lipids?

hydrophobic lipids, amphiphatic lipids

What are the two main solubility classifications of lipids?

hydrophobic lipids

These are lipids containing mainly nonpolar groups, making them insoluble in water

amphiphatic lipids

Lipids with both a hydrophilic polar region and a hydrophobic nonpolar region

mainly as triacylglycerols stored in adipose tissue

How do lipids function in energy storage?

cell membranes

How do lipids function structurally? They are major components of what?

signaling molecules or hormone precursors

How do lipids function in signaling?

myelin lipids

What lipid is important for nerve impulse conduction which electrically insulate nerve fibers?

simple lipids

These are esters of fatty acids and alcohols

fatty acids and alcohol

Simple lipids are esters of?

fats/oils, waxes

What are the major types of simple lipids?

glycerol

What is the alcohol backbone of fats and oils?

long-chain monohydric alcohols

What alcohol is found in waxes?

FA + alcohol = ester

What is the general reaction for forming a simple lipid? The general structure

complex lipids

These are lipids containing fatty acids, an alcohol, and additional groups

complex lipids

These are lipids with esters of fatty acids containing an alcoholand one or more fatty acids

phospholipids, glycolipids, other complex lipids

What are the major types of complex lipids?

FA + alcohol + phosphate group

What is the basic composition of a phospholipid?

nitrogen bases

Phospholipids often contain what type of base?

choline

Phospholipids often contain nitrogen bases like?

glycerophospholipids

What type of phospholipids have glycerol as its alcohol?

sphingophospholipids

What type of phospholipids have sphingosine as its alcohol?

FA + sphingosine + carbohydrate

What is the basic composition of a glycolipids?

glycosphingolipids

Glycolipids are also known as?

glycolipids

This type of complex lipid is used for cell stability, adhesion, and cell-cell interaction

sulfolipids, amino lipids, lipoproteins

What are the three other complex lipids?

sulfolipids

This complex lipid contain sulfate group on sugar

amino lipids

This complex lipid contain nitrogen group

lipoproteins

This complex lipid contain protein for transport, structure, antigen, and toxins

precursor lipids

These are molecules that participate in forming simple and complex lipids

fatty acids, glycerol

Examples of precursor lipids

derived lipids

These are lipids produced by metabolic transformation of FA or hydrolysis of simple and complex lipids

derived lipids

What type of lipids are steroids, ketone bodies, fatty aldehydes, lipid-soluble vitamins, and hormones?

vitamin A

What is beta-carotene a precursor of?

they are uncharged molecules

Why are neutral lipids called neutral?

neutral lipids

Acylglycerols, cholesterol, and cholesterol esters are examples of?

four-fused rings, a hydrocarbon chain, a hydroxyl group

What are the major structural components of cholesterol?

3 six-carbon rings, 1 five-carbon ring

What does the four fused rings?

carbon 3

Where is the hydroxyl group located in cholesterol?

The hydroxyl (-OH) group at C3

Which part of cholesterol is polar?

straight hydrocarbon chain + carboxy group (-COOH)

What is the basic structure of a fatty acid?

polar, hydrophilic end: carboxyl group; nonpolar hydrophobic end: methyl group (-CH3)

What are the two ends of a fatty acid?

CH3-(CH2)n-COOH

What is the general formula of a saturated fatty acid?

carboxyl group (-COOH)

Which part of a fatty acid is hydrophilic?

hydrocarbon chain, methyl (-CH3) end

Which part of a fatty acid is hydrophobic?

as esters

In what form are fatty acids mainly found in natural fats and oils?

free fatty acids (FFA)

What are unesterified fatty acids called?

as FFA

In what form are fatty acids transported in plasma?

precursors for simple and complex lipids

What is the role of fatty acids in lipid synthesis?

major energy nutrient, storage molecule

What iss the major metabolic role of fatty acids? They serve as?

saturated FA

A fatty acid whose hydrocarbon chain contains only single C-C bonds

saturated

Fatty acid is classified as this as it has the maximum possible number of hydrogen atoms

unsaturated FA

This fatty acid contains at least one C=C double bond

C=C double bonds

Why doo unsaturated fatty acids have fewer hydrogen atoms? The presence of ____ reduces the number of hydrogen atoms that can be attached

straight and flexible

What is the carbon backbone of saturated fatty acids like?

C=C double bonds, creating rigid bend

What causes the “kinks” in unsaturated fatty acids?

saturated FA

Which fatty acids allow tighter packing?

saturated FA

At room temperature, are lipid rich in saturated or unsaturated FA usually solid?

unsaturated

At room temperature, are lipids rich in saturated or unsaturated FA usually liquid?

unsaturated FA, due to their double bonds

Which is relatively more polar? Saturated or unsaturated FA?

nonpolar, due to long hydrocarbon chain

Are fatty acids overall polar or nonpolar?

carbon atoms, double bonds

How are fatty acids named? Based on the total number of ____ and the number/position of ____

-oic acid

What suffix is used for saturated FA?

-enoic acid

What suffic is used for unsaturated FA?

hexadecanoic acid

What is the systemic name of a 16-carbon saturated FA?

palmitic acid

Hexadecanoic acid is also known as?

Octadec-9-enoic acid

What is the systemic name of an 18-carbon FA with one double bond at C9?

From the carboxyl carbon (C1)

From which end is the double-bond position counted?

18 carbon atoms

In octadec-9-enoic acid, what does octadec indicate?

double bond starts at C9

In octadec-9-enoic acid, what does 9 indicate?

number of carbon atoms

How do you determine the name of an saturated FA?

number of carbon atoms, position and number of double bonds

How do you determine the name of an unsaturated FA?

20 carbon atoms

What does eicos- indicate?

5 double bonds

What does penta- indicate in FA nomenclature?

unsaturated

What does -enoic acid indicate? The fatty acid is?

5,8,11,14,17-eicosapentaenoic acid

What is the name of a 20-carbon FA with double bonds at C5, C8, C11, C14, and C17?

lower-numbered carbon

How is the position of a double bond annotated? Using the ______ involved in the double bond

5-

If a double bond is between C5 and C6, how is its position written?

8-

If a double bond is between C8 and C9, how is its position written?

rotate

Why are saturated FA flexible? Their C-C single bonds can what?

fully extended confirmation

What is the most stable conformation of a saturated FA?

closely, rigid arrays

How do saturated FA pack? Then this forms?

animal fats

Where are saturated FA commonly found?

palmitic acid, stearic acid

What are examples of saturated FA?

hexadecanoic acid

Palmitic acid is also known as?

octadecanoic acid

Stearic acid is also known as?

MUFA, PUFA

What are the two major types of unsaturated FA?

monounsaturated FA, 1

What does MUFA stand for? How many double bond does it contain?

polyunsaturated FA, more than 1

What does PUFA stand for? How many double bond does it contain?

oleic acid

What is an example of a MUFA?

linoleic acid

What is an example of a PUFA?

20-carbon PUFA

What are eicosanoids derived from?

prostaglandins, leukotrienes

What are examples of eicosanoids?

plants

Where are unsaturated FA especially abundant?

freely rotate

Why does geometric isomerism occur in unsaturated FA? Because the C=C double bonds cannot?

orientation of groups around the double bond

What determines whether an unsaturated FA is cis or trans?

same, bent/kinked

What is the cis form of an unsaturated FA? Hydrogens are on the ___ side of the double bond, producing a ___ chain