Organic Chemistry Chapter 17 Lipids and their functions in biochemical systems

which class of biological molecules can act as an energy source, a hormone, a vitamin, an energy storage, and a structural component in cell membranes?

Lipids

In sphingomyelins, the single fatty acid is bonded to the carbon backbone by a(n) _____ bond.

amide

which of the following is considered to be an omega-3 fatty acid?

linolenic acid

which of the following are essential fatty acids?

linolenic acid and linoleic acid

A cell membrane is composed of ____.

lipid bilayers with the ionic heads oriented to the outside of the bilayer and the nonpolar tails on the inside

describe the properties of lipids

lipids are biomolecules lipids are identified based on their solubility

As the length of the hydrocarbon chain of saturated fatty acids increases, what is the effect on the melting point?

melting point increases

lipids are soluble in ____

organic solvents

the steroid ____ is responsible for the successful initiation and completion of pregnancy

progesterone

What molecules are formed from arachidonic acid?

prostaglandins

omega-3

prostaglandins with anti-inflammatory effects

omega-6

prostaglandins with inflammatory effects

cortisone

regulation of carbohydrate metabolism

estrone

regulation of female sexual development

aldosterone

regulation of sodium in the blood

what type of chemical reaction is used to prepare a soap

saponification

At room temperature, what would be the physical state of a triglyceride with three saturated fatty acid tails?

solid

what is the shape of a lipoprotein

spherical

the coating that surrounds and insulates nerve cells, the myelin sheath, is rich in____.

sphingomyelins

What are two major types of sphingolipids?

sphingomyelins glycosphingolipids

the principle function of triglycerides in biochemical systems is

storage of energy

which of the following are types of glycosphingolipids?

sulfatides, cerebrosides (found in the membrane of brain cells), gangliosides (first isolated from nerve cells)

this R" group is not used in phosphoglycerides

(CH2CH2)2N(CH3)2+

which of the following structural features are part of a prostaglandin?

*Five membered ring *carboxylic acid

which of the following are features of eicosanoids?

*arachidonic acid is the precursor for eicosanoids, *prostaglandins, leukotrienes, and thromboxanes are types of eicosnoids

how many fatty acid molecules are needed to make one molecule of a phosphoglyceride

2

which of the following are unsaturated fatty acids?

linoleic acid and oleic acid

how many carbons are in the rings of the steroid skeleton

17

the simplest phosphoglyceride, known as phosphatidate =, contains a phosphoryl group attached to ___ of glycerol

C-3

cephalin

CH2CH2NH3+

Lecithin

CH2CH2n(CH3)3+

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

In saturated fatty acids, each carbon is bound to the maximum number of hydrogens. In unsaturated fatty acids, there is at least one carbon-to-carbon double bond.

what do terms omega-3 and omega-6 indicate about the structures of the fatty acids in those classifications?

In ω -6 fatty acids, the double bond nearest the ω methyl group is six carbons along the chain. In ω -3 fatty acids, the double bond nearest the ω methyl group is three carbons along the chain.

which of the following is synthesized in the testes?

Testosterone

How will the properties of a biological membrane change if the fatty acid tails of the phospholipids are converted from saturated to unsaturated chains?

The fluidity of the membrane will increase.

What is the basic structure of a biological membrane?

The hydrophobic hydrocarbon tails are packed in the center. The hydrophilic head groups are exposed on the inner and outer surfaces.

What are the structural differences between triglycerides (triacylglycerols) and phospholipids?

Triglycerides consist of three fatty acids esterified to the three hydroxyl groups of glycerol. Phospholipids consist of two fatty acids esterified to glycerol and a phosphoryl group esterified to the third hydroxyl group.

phosphoglycerides

a glyceride containing a polar phosphoryl group

neutral glycerides

a glyceride formed from the esterification of glycerol and one or more fatty acids

which of the following are the products of an acid-catalyzed hydrolysis of a triacylglycerol in water?

a glycerol molecule and three fatty acid molecules

which statement about fatty acids is correct?

an unsaturated fatty acid has a lower melting point than a saturated fatty acid with a similar molar mass.

soaps are obtained from the ___ hydrolysis of an ester

base-catalyzed

VLDL

bind triglycerides synthesized in the liver and carry them to adipose tissue for storage

What is one function of the essential fatty acids?

biosynthesis of arachidonic acid

which of the following biological processes are regulated by prostaglandins, leukotrienes and thromboxanes?

blood clotting, inflammatory response, asthma, bronchodilation, and uterine contractions

identify the functional group present in fatty acids

carboxyl group

LDL

carry cholesterol to peripheral tissue and help regulate cholesterol levels in those tissues

chylomicrons

carry dietary triglycerides from intestines to other tissues

which of the following correctly describe cholesterol

cholesterol is the starting material for the biosynthesis of steroid based hormones, cholesterol is a component of cell membranes

which of the following molecules are contained in a cell membrane

cholesterol, glycolipids, phospholipids, glycoproteins

which statement correctly describes the actions of emulsifying agents

emulsifying agents are amphipathic and can bridge the nonpolar triglyceride with the polar water molecules

in a(n) _____ reaction, fatty acids react with alcohols to form esters and water

esterification

identify the chemical reactions of fatty acids and glycerides

esterification, hydrogenation, saponification, hydrolysis

waxes are ____.

esters

Select the four main groups of lipids.

fatty acids glycerides complex lipids nonglyceride lipids

identify the products from the base-catalyzed hydrolysis (saponification) of a trigylceride

glycerol and three carboxylate salts

What are the four major types of plasma lipoproteins?

high-density lipoproteins low-density lipoproteins chylomicrons very low-density lipoproteins

hydrogenation involves the addition of _____ to the carbon-carbon double bond of a fatty acid

hydrogen

which of the following are the products of an acid-catalyzed hydrolysis of a triacylglycerol in water

three fatty acid molecules a glycerol molecule

HDL

transport cholesterol from peripheral tissues to the liver

which class of fatty acids when incorporated into a phospholipid contributes to membrane fluidity

unsaturated fatty acids