Chapter 20

How many chiralty centers in galactose?

4

Which of the following statements correctly describe a Fischer projection formula? Select all that apply. Multiple select question. Hydrogen atoms do not need to be labeled. A carbon atom is located at the intersection of two lines of the cross. The intersection of any two lines represents a tetrahedral carbon atom. Horizontal bonds project behind the plane of the drawing. The vertical bonds are equivalent to wedged lines.

A carbon atom is located at the intersection of two lines of the cross. The intersection of any two lines represents a tetrahedral carbon atom.

Which of the following statements correctly describe the use of Benedict's reagent in the oxidation of aldoses to aldonic acids? Select all that apply. Multiple select question. Benedict's reagent contains a Pd catalyst. Benedict's reagent is the blue-colored Cu2O. A color change from blue to red is seen as the oxidation of the aldose takes place. During the oxidation Cu2+ is reduced to Cu+.

A color change from blue to red is seen as the oxidation of the aldose takes place. During the oxidation Cu2+ is reduced to Cu+.

Which two functional groups are attached to the same carbon in a hemiacetal? Select all that apply. Multiple select question. A carbonyl group Two hydroxyl (OH) groups A hydroxyl (OH) group An alkoxy (OR) group Two alkoxy (OR) groups

A hydroxyl (OH) group An alkoxy (OR) group

Monosaccharides, disaccharides, and polysaccharides are all types of __

Carbohydrates

Which of the following statements correctly describe carbohydrates? Select all that apply. Carbohydrates include sugars and starches. Carbohydrates are hydrates of amino acids. Carbohydrates include only polyhydroxy aldehydes. Simple carbohydrates are hydrates of carbon with the formula Cn(H2O)n.

Carbohydrates include sugars and starches. Simple carbohydrates are hydrates of carbon with the formula Cn(H₂O)n.

Which of the following statements correctly describe the process of metabolism? Select all that apply. Multiple select question. Glucose and oxygen are formed from the process of metabolism. Chemical energy stored in glucose is released when glucose is metabolized. Metabolism is an oxidative process. The metabolism of lipids produces more energy per gram than the metabolism of carbohydrates.

Chemical energy stored in glucose is released when glucose is metabolized. Metabolism is an oxidative process. The metabolism of lipids produces more energy per gram than the metabolism of carbohydrates.

Which of the following statements correctly describe the structure of sucrose? Select all that apply. Multiple select question. Sucrose is composed of the monosaccharides glucose and galactose. Sucrose has a 1→4 β glycosidic linkage Sucrose contains a five-membered ring and a six-membered ring. The anomeric carbons of both components participate in the glycosidic linkage.

Sucrose contains a five-membered ring and a six-membered ring. The anomeric carbons of both components participate in the glycosidic linkage.

Which of the following statements correctly describe an anomeric carbon? Select all that apply. Multiple select question. The carbon atom attached to the OH group in the starting material becomes the anomeric carbon. The anomeric carbon is a chirality center formed when a monosaccharide forms a cyclic hemiacetal. The α anomer of a cyclic hemiacetal has the OH group drawn up, above the ring. Two anomers may be formed when an intramolecular cyclization takes place to give a hemiacetal.

The anomeric carbon is a chirality center formed when a monosaccharide forms a cyclic hemiacetal. Two anomers may be formed when an intramolecular cyclization takes place to give a hemiacetal.

Monosaccharide containing a ketone group and 4 carbons

ketotetrose

Glucose is converted into water and carbon dioxide in the process of _____.

metabolism

a carbohydrate that cannot be hydrolyzed to simpler compounds.

monosaccharide

The simplest of all carbohydrates are called _____, whereas _____ are composed of three or more of these simple sugars joined together to form a carbohydrate such as starch.

monosaccharides, polysaccharides

Aldoses are _____ with _____ to give aldonic acids.

oxidized, Benedict's reagent

monosaccharide with 5 carbon atoms

pentose

contains three or more monosaccharides joined together. Some examples are cellulose, strach, and glycogen.

polysaccharide

Cellulose is an unbranched ______________ composed of repeating ___________________ units joined by a 1→4-β-glycosidic linkage.

polysaccharide; D-glucose

Sugars that are oxidized by Benedict's reagent are called _____ sugars.

reducing

carbohydrate that is oxidized with Benedict's reagent.

reducing sugar

Glucose storage polysaccharide in plants

starch

Ketoses are

sugars with a ketone functional group

monosaccharide with 4 carbon atoms

tetrose

Monosaccharides generally contain _____ carbon atoms in a chain with a _____ group at either C1 or C2. Multiple choice question. four to eight; carbonyl three to six; carbonyl three to six; carboxyl three to five; carboxyl

three to six; carbonyl

monosaccharide with 3 carbon atoms

triose

Groups that are on the left in the Fischer projection should be __ in the Haworth projection.

up

Photosynthesis is a process that _____.

uses the energy from the sun to convert CO2 and H2O into glucose and oxygen

Which of the following options correctly describe polysaccharides? Select all that apply. Multiple select question. Monosaccharides are linked by C-C bonds to form polysaccharides. A single polysaccharide may contain different types of glycosidic linkages. Polysaccharides are often composed of repeating units of monosaccharides. The monosaccharides in a polysaccharide are linked by glycosidic bonds.

A single polysaccharide may contain different types of glycosidic linkages. Polysaccharides are often composed of repeating units of monosaccharides. The monosaccharides in a polysaccharide are linked by glycosidic bonds.

Which of the following statements correctly describe aldonic acids? Select all that apply. Multiple select question. Aldonic acids are formed upon reduction of aldoses. Aldoses and ketoses react with Benedict's reagent to give aldonic acids. Aldonic acids are carboxylic acids. An aldonic acid has a carboxylic acid group at both ends of the carbon chain.

Aldoses and ketoses react with Benedict's reagent to give aldonic acids. Aldonic acids are carboxylic acids.

Which of the following statements correctly describe the reduction of the carbonyl group of an aldose? Select all that apply. Multiple select question. Aldoses are reduced using H2 in the presence of palladium metal. Aldoses may be reduced to alditols. The product of reduction of an aldose is an alcohol. Aldoses may be reduced to aldonic acids.

Aldoses are reduced using H2 in the presence of palladium metal. Aldoses may be reduced to alditols. The product of reduction of an aldose is an alcohol.

Many carbohydrates contain hemiacetals. How is a hemiacetal formed? Multiple choice question. A carboxylic acid reacts with one equivalent of an alcohol. Two different alcohols react with each other. An aldehyde or ketone reacts with one equivalent of an alcohol. An ether reacts with one equivalent of an alcohol.

An aldehyde or ketone reacts with one equivalent of an alcohol.

In a disaccharide, a glycosidic linkage is ______.

C-O bond that joins two monosaccharides

Which of the following statements correctly describe galactose? Select all that apply. Multiple select question. Galactose is an aldohexose that contains 5 chirality centers. Galactose is one of two monosaccharides that make up lactose. Galactosemia is an inherited disease where individuals lack an enzyme needed to metabolize galactose. Galactose is a stereoisomer of glucose.

Galactose is one of two monosaccharides that make up lactose. Galactosemia is an inherited disease where individuals lack an enzyme needed to metabolize galactose. Galactose is a stereoisomer of glucose.

Which of the following statements correctly describe the monosaccharide glucose? Select all that apply. Multiple select question. Glucose levels are regulated in the body by a protein known as insulin. Glucose is the building block for polysaccharides such as starch and cellulose. The most common monosaccharides are the ketohexoses D-glucose and D-galactose. Glucose is also known as dextrose. Normal blood glucose levels are in the region of 170-210 mg/dL.

Glucose levels are regulated in the body by a protein known as insulin. Glucose is the building block for polysaccharides such as starch and cellulose. Glucose is also known as dextrose.

Which of the following statements correctly describe the steps required to convert a Fischer projection of D-glucose into its six-membered hemiacetal forms (anomers)? Select all that apply. Multiple select question. Groups that are on the right side of the Fischer projection will be below the plane of the ring. Draw the cyclic hemiacetal formed by reaction of the OH group on C5 with the aldehyde carbonyl. The CH2OH group at the end of the chain (C6) will be below the plane of the ring. Rotate the carbon skeleton (Fischer projection) 90o in a counterclockwise direction. Twist the chain to put the OH group on C5 close to the aldehyde carbonyl.

Groups that are on the right side of the Fischer projection will be below the plane of the ring. Draw the cyclic hemiacetal formed by reaction of the OH group on C5 with the aldehyde carbonyl. Twist the chain to put the OH group on C5 close to the aldehyde carbonyl.

A flat, six-membered ring structure used to represent the cyclic hemiacetals of glucose and other sugars is known as a _____.

Haworth Projection

planar, six-membered ring used to represent the cyclic form of glucose and other sugars.

Haworth Projection

Which of the following options correctly describe hydrolysis of a disaccharide? Select all that apply. Multiple select question. Hydrolysis of a disaccharide results in cleavage of the glycosidic linkage. The internal C-O bonds in each ring are cleaved. Two monosaccharides are formed. The ring structure of the disaccharide is converted to an acyclic structure.

Hydrolysis of a disaccharide results in cleavage of the glycosidic linkage. Two monosaccharides are formed.

Which class of carbohydrates includes the monosaccharide fructose? Multiple choice question. Ketohexoses Aldopentoses Ketopentoses Aldohexoses

Ketohexoses

Which types of monosaccharides tend to form five-membered rings in solution, rather than six-membered rings? Select all that apply. Multiple select question. Ketohexoses Aldohexoses Aldopentoses

Ketohexoses Aldopentoses

Which of the following statements correctly describe properties of monosaccharides? Select all that apply. Multiple select question. Monosaccharides are capable of hydrogen bonding with water molecules. Monosaccharides have low melting points. Monosaccharides taste sweet. Most monosaccharides are insoluble in water. Monosaccharides are polar compounds.

Monosaccharides are capable of hydrogen bonding with water molecules. Monosaccharides taste sweet. Monosaccharides are polar compounds.

Test strips used for measuring glucose concentration in urine are based on which reaction?

The oxidation of glucose to gluconic acid

All disaccharides contain at least one _____ that forms part of the link between the two rings.

acetal

Aldoses are

aldehydes

Aldoses are reduced to _____ using _____ in the presence of palladium metal.

alditols, H2

Monosaccharide containing aldehyde group with 5 carbon atoms

aldopentose

A monosaccharide with a four-carbon chain and a carbonyl group at the terminal carbon (C1) is correctly classified as a(n) _____. Multiple choice question. aldose hexose pentose ketose

aldose

Monosaccharides with an aldehyde carbonyl group at C1

aldoses

The glycosidic linkage is oriented down, below the plane of the ring that contains the acetal joining the monosaccharides.

alpha

When a monosaccharide forms a cyclic hemiacetal, the carbon atom attached to both the OH and OR groups is called the _____ carbon.

anomeric

A compound that contains both a(n) _____ group and a(n) ______ can undergo an intramolecular cyclization reaction to form a cyclic hemiacetal.

carbonyl; OH

glyceraldehyde and dihydroxyacetone are

constitutional isomers

The simplest ketose is

dihydroxyacetone

All carbohydrates except for _____ contain one or more _____.

dihydroxyacetone, chirality centers

Carbohydrates may be classified as ______. Select all that apply. Multiple select question. disaccharides monosaccharides galactoses polysaccharides sucroses

disaccharides monosaccharides polysaccharides

The configuration of the chirality center _____ the carbonyl group determines whether a monosaccharide is D or L. If the OH group is on the right-hand side the monosaccharide is of the _____ form.

farthest from, D

The disaccharide lactose contains

galactose and glucose.

Starch is a polymer composed of repeating units of the monosaccharide _____ joined by _____ glycosidic linkages.

glucose; a

The simplest aldose is

glyceraldehyde

Glucose storage polysaccharide in animals

glycogen

The C-O bond that joins two monosaccharides together is the

glycoside linkage

monosaccharide with 6 carbon atoms

hexose

Simple carbohydrates have a general molecular formula that can be written as Cn(H2O)n, making them _______ of carbon.

hydrates

Carbohydrates are polyhdroxy aldehydes or ketones, or a compound that can be ________________ to a polyhydroxy aldehyde or ketone.

hydrolyzed

A compound that contains both a hydroxyl group and a carbonyl group can undergo a(n) _____ cyclization reaction to form a stable _____ hemiacetal.

intramolecular, cyclic