Chemistry Final

The coating that surrounds and insulates nerve cells, the myelin sheath, is particularly rich in sphingomyelins, and is vital for proper nerve function.

True

The three-dimensional structure of a trans triacylglycerol shows its similarity to saturated triacylglycerols.

True

Trans double bonds can be formed when triacylglycerols are partially hydrogenated.

True

Vitamins are organic compounds required in small quantities for normal metabolism

True

When a monosaccharide forms a cyclic hemiacetal, the carbon atom that is part of the hemiacetal is a new chirality center, called the anomeric carbon.

True

Which is not a fat-soluble vitamin?

Vitamin C

Which statement is not true?

Vitamin E is an oxidizing agent, oxidizing the unsaturated side chains in fatty acids.

The structure of lipids is

dominated by hydrophobic regions

When converting a Fischer projection to a Haworth projection, where are all of the substituents on the right side of the carbon skeleton drawn in the Haworth projection?

down

Hydrolysis of triacylglycerols in the body occurs with the aid of which reagent?

enzymes

What functional group is contained in most hydrolyzable lipids?

ester

What process is used to move large polar molecules and ions, such as Cl- and HCO3-, through a cell membrane, traveling from the side of higher concentration to the side of lower concentration?

facilitated transport

What is the structure of cellulose?

unbranched skeleton of glucose molecules joined by 14--glycoside linkages

Lipids are defined as biomolecules that contain fatty acids as part of their structure.

False

Soap is prepared by the acid hydrolysis (saponification) of a triacylglycerol.

False

Certain monosaccharides—notably aldopentoses and ketohexoses—form five-membered rings, not six-membered rings, in solution.

True

Eicosanoids are a group of biologically active compounds containing 20 carbon atoms derived from the fatty acid arachidonic acid.

True

Glucose and other naturally occurring sugars are D sugars.

True

Prostaglandins are a group of carboxylic acids that contain a five-membered ring, and are responsible for inflammation.

True

Saturated fatty acids have no double bonds in their long hydrocarbon chains.

True

How many triacylglycerols can be prepared from two different fatty acids?

4

Which of these groups of compounds are phospholipids?

sphingomyelins

Which compound is the most soluble in water?

CH2OHCHOHCHOHCHOHCHOHCHO

Which compound has the highest melting point?

CH3(CH2)14COOH

What hydrolysis products are formed when the wax CH3(CH2)18COO(CH2)17CH3 is treated with aqueous sulfuric acid?

CH3(CH2)18COOH + CH3(CH2)16CH2OH

Which compound has the lowest melting point?

CH3(CH2)2CH=CH(CH2)2CH=CH(CH2)2CH=CH(CH2)2COOH

Complete metabolism of a triacylglycerol yields which of the following?

CO2, H2O, and a great deal of energy

Tamoxifen is a widely used anti-estrogen drug used to treat tumors of the breast. Tamoxifen would be considered a hydrophilic molecule, having limited solubility in water and blood, and high solubility in fat.

False

Which statement is not true?

Cholesterol cannot be synthesized in the body, and therefore is required in the diet.

The anomer of a cyclic monosaccharide has the -OH group drawn down, below the ring.

False

Triacylglycerols form lipid bilayers.

False

Which labeled carbon atom in the structure below is the anomeric carbon

D

Fats contain a larger percentage of unsaturation in their structures than oils do.

False

-D-galactose and -D-galactose are enantiomers.

False

A hemiacetal is a compound that contains a hydroxyl group (-OH) and an alkoxy group (-OR) on adjacent carbon atoms.

False

An individual can survive on a completely fat-free diet.

False

At equilibrium, a solution of glucose in water is an equal mixture of the anomer, the anomer, and the acyclic aldehyde.

False

Fats and oils are structurally both triacylglycerols, but fats are solids at room temperature and oils are liquids at room temperature. Which statement best describes the reason for their difference in physical state?

Fats contain a higher percentage of saturated fatty acids than oils do, and therefore have higher melting points than oils.

In addition to the three monosaccharides that occur in all blood types, type A blood contains the monosaccharide N-acetyl-D-galactosamine, and type B blood contains an additional D-galactose unit.

True

Individuals with type AB blood are called universal recipients because their blood contains no antibodies to blood types A, B, or O. Individuals with type AB blood can receive blood of any type.

True

Lipids come in a wide variety of structures and have many different functions.

True

Why are humans not able to digest cellulose?

Humans do not possess the enzyme necessary to hydrolyze the 14--glycoside linkages found in cellulose.

Which statement concerning carbohydrates is incorrect?

Humans store excess glucose for short term energy requirements in the polysaccharide cellulose.

The contents on a box of cupcakes lists partially hydrogenated soybean oil. Partial hydrogenation of soybean oil has what effect?

It decreases the percent of unsaturation that is present.

Modern glucose meters are electronic devices that measure the amount of oxidizing agent that reacts with the glucose in a known amount of blood.

True

Monosaccharides with a carbonyl group at C2 are called ketoses.

True

Which statement concerning lipid functions is incorrect?

Plants and animals use waxes for insulation.

Which is not true about prostaglandins?

Prostaglandins decrease inflammation.

Salicin is a naturally occurring, carbohydrate-containing pain reliever. Which statement concerning the functional groups present in salicin is incorrect?

Salicin contains a phenol.

What is the difference between the disaccharides lactose and maltose?

The two monosaccharides in lactose are joined by a 14--glycoside bond, while the two monosaccharides in maltose are joined by a 14--glycoside bond.

Carbohydrates are structurally defined as polyhydroxyaldehydes and polyhydroxyketones, or compounds that can be hydrolyzed to them.rue

True

Carbohydrates serve important energy and structural roles for both plants and animals.

True

Carbohydrates that are oxidized with Benedict's reagent are called reducing sugars, because they reduce the Cu2+ in Benedict's reagent to Cu+ during the reaction.

True

The block diagram for a phosphoacylglycerol (glycerophospholipid) is shown below. Phosphoacylglycerols can interact with both water and other lipids, and therefore are well suited for their role in the lipid bilayer of cell membranes. Which statement best explains this behavior?

They contain both a hydrophobic region as well as a hydrophilic region.

All carbohydrates, except for dihydroxyacetone, contain one or more chirality centers.

True

All disaccharides contain at least one acetal that joins the rings together.

True

An glycoside has the glycosidic linkage oriented down, below the plane of the ring that contains the acetal joining the monosaccharides.

True

An alditol contains an -OH group on every carbon atom.

True

Waxes are formed from the reaction between which two types of compounds?

a fatty acid and a high molecular weight alcohol

Which structural feature is not found in sphingomyelins?

a glycerol backbone

What are monosaccharides with a carbonyl group at C1 called?

aldoses

What is the most common type of starch molecules?

amylopectin

Which is a nonhydrolyzable lipid?

an eicosanoid

What is the structure of amylopectin?

branched skeleton of glucose molecules joined by 14--glycoside linkages

The formation of what color in the Benedict's test indicates a reducing sugar is present in solution?

brick red

Which is not an anabolic steroid?

cortisone

Lactose is present in milk. What type of sugar is lactose?

disaccharide

What monosaccharide is found in cellulose, starch, and glycogen?

glucose

What is the polysaccharide form in which glucose is stored in animals?

glycogen

Disaccharides and polysaccharides contain monosaccharide units joined together by which of the following?

glycosidic linkages

Cetyl palmitate is a component of spermaceti wax isolated from the heads of sperm whales, and is used in cosmetics. In which solvent would cetyl palmitate be expected to have the greatest solubility?

hexane

Which carbohydrates cannot be converted to simpler compounds by hydrolysis?

monosaccharides

Which type of fatty acid is most common in olive oil?

monounsaturated

What designation best describes linolenic acid, whose structure is shown below?

omega-3 acid

Which is not an example of a lipid?

phenol

Which is a hydrolyzable lipid

phosphoacylglycerol

What is the main component of the cell membrane?

phospholipids

Unlike most oils, which type of fatty acid is most common in coconut oil?

saturated

The structures of galactose (left) and glucose (right) are shown below. How are the two monosaccharides related?

stereoisomers

Which is not a reducing sugar?

sucrose

What is responsible for the different blood types in humans?

three or four monosaccharides attached to a membrane protein on the surface of red blood cells

Which is a hydrolyzable lipid?

triacylglycerol