Podcast
Questions and Answers
What is the total number of isomers for a hexose with four asymmetric carbons according to Le Bel-van’t Hoff rule?
What is the total number of isomers for a hexose with four asymmetric carbons according to Le Bel-van’t Hoff rule?
Which stereoisomer is classified as non-superimposable mirror images of each other?
Which stereoisomer is classified as non-superimposable mirror images of each other?
Which of the following statements about geometric isomers is true?
Which of the following statements about geometric isomers is true?
What happens to a mixture of equal amounts of D and L forms of a compound?
What happens to a mixture of equal amounts of D and L forms of a compound?
Signup and view all the answers
What type of projection is used to represent the linear form of monosaccharides?
What type of projection is used to represent the linear form of monosaccharides?
Signup and view all the answers
What is the result of adding alcohol to the carbonyl group of an aldehyde or ketone?
What is the result of adding alcohol to the carbonyl group of an aldehyde or ketone?
Signup and view all the answers
Which member ring structure is formed when a 5 or 6 membered ring is created during the addition of alcohol?
Which member ring structure is formed when a 5 or 6 membered ring is created during the addition of alcohol?
Signup and view all the answers
Why are hemiacetals and hemiketals usually present in only small amounts in an equilibrium mixture?
Why are hemiacetals and hemiketals usually present in only small amounts in an equilibrium mixture?
Signup and view all the answers
In converting a D-sugar to the Haworth projection, where is the –CH2OH group located?
In converting a D-sugar to the Haworth projection, where is the –CH2OH group located?
Signup and view all the answers
Which statement best describes the formation of stable 6 membered rings from a six-carbon aldose?
Which statement best describes the formation of stable 6 membered rings from a six-carbon aldose?
Signup and view all the answers
What is the main reason for using lactose in the pharmaceutical industry?
What is the main reason for using lactose in the pharmaceutical industry?
Signup and view all the answers
Which of the following statements is true about maltose?
Which of the following statements is true about maltose?
Signup and view all the answers
Which statement describes a property of lactose?
Which statement describes a property of lactose?
Signup and view all the answers
What distinguishes maltose from other disaccharides?
What distinguishes maltose from other disaccharides?
Signup and view all the answers
In industrial applications, what role does maltose play in ice cream production?
In industrial applications, what role does maltose play in ice cream production?
Signup and view all the answers
What is the primary structural composition of chitin?
What is the primary structural composition of chitin?
Signup and view all the answers
Which of the following statements about chitin is incorrect?
Which of the following statements about chitin is incorrect?
Signup and view all the answers
Which application of chitosan is primarily related to its antimicrobial properties?
Which application of chitosan is primarily related to its antimicrobial properties?
Signup and view all the answers
In which of the following industries is chitin NOT typically utilized?
In which of the following industries is chitin NOT typically utilized?
Signup and view all the answers
What is one of the significant characteristics of chitin that makes it favorable for surgical thread?
What is one of the significant characteristics of chitin that makes it favorable for surgical thread?
Signup and view all the answers
Which of the following functions is NOT associated with hyaluronic acid?
Which of the following functions is NOT associated with hyaluronic acid?
Signup and view all the answers
What linkage types are found in hyaluronic acid?
What linkage types are found in hyaluronic acid?
Signup and view all the answers
Which polysaccharide is primarily responsible for the structural integrity of cartilage?
Which polysaccharide is primarily responsible for the structural integrity of cartilage?
Signup and view all the answers
What is the primary biological role of heparin?
What is the primary biological role of heparin?
Signup and view all the answers
Which statement about chondroitin sulfate is false?
Which statement about chondroitin sulfate is false?
Signup and view all the answers
What is produced when hyaluronic acid is hydrolyzed by hyaluronidase?
What is produced when hyaluronic acid is hydrolyzed by hyaluronidase?
Signup and view all the answers
Which of the following is NOT commonly a use of hyaluronic acid?
Which of the following is NOT commonly a use of hyaluronic acid?
Signup and view all the answers
What type of saccharide does heparin primarily consist of?
What type of saccharide does heparin primarily consist of?
Signup and view all the answers
Which of the following statements accurately reflects the role of glycogen in the body?
Which of the following statements accurately reflects the role of glycogen in the body?
Signup and view all the answers
What is a key difference between starch and cellulose regarding solubility?
What is a key difference between starch and cellulose regarding solubility?
Signup and view all the answers
What industrial application is starch NOT used for?
What industrial application is starch NOT used for?
Signup and view all the answers
Which statement about cellulose digestion is accurate?
Which statement about cellulose digestion is accurate?
Signup and view all the answers
Among the following, which is a biological importance of glycogen?
Among the following, which is a biological importance of glycogen?
Signup and view all the answers
Identify the correct distinction between glycogen and amylopectin.
Identify the correct distinction between glycogen and amylopectin.
Signup and view all the answers
Which of the following polysaccharides is primarily responsible for dietary fiber in humans?
Which of the following polysaccharides is primarily responsible for dietary fiber in humans?
Signup and view all the answers
What color does iodine solution produce when reacted with glycogen?
What color does iodine solution produce when reacted with glycogen?
Signup and view all the answers
Study Notes
Carbohydrate Chemistry
- Carbohydrates have the general formula C6H12O6
- Carbohydrates are classified into four groups: monosaccharides, disaccharides, polysaccharides, and oligosaccharides.
- Monosaccharides are simple sugars that cannot be broken down into smaller groups.
- Monosaccharides have the general formula (CH2O)n.
- Monosaccharides can be further classified based on the number of carbon atoms (triose, tetrose, pentose, hexose, heptose), the position of the carbonyl group (aldose, ketose), and chirality.
- The names of monosaccharides depend on the number of carbon atoms present and the suffix -ose.
- Examples of monosaccharides include trioses such as glyceraldehyde and dihydroxyacetone, pentoses such as ribose and ribulose, and hexoses such as glucose, galactose, and fructose.
- Chirality refers to an object that is not superimposable on its mirror image.
- The letter D- or L- is used before the name of the monosaccharide to distinguish isomers.
- A chiral carbon has four different groups bonded to it.
- For longer monosaccharides, there will be more than one asymmetric carbon.
- Isomerism occurs due to the presence of asymmetric carbon
- Two main types of isomers include constitutional and stereoisomers.
- Stereoisomers include geometric and optical isomers.
- Geometric isomers, cis-trans isomers, are not applicable to monosaccharides, usually occurs in unsaturated compounds having double bonds.
- Optical isomers, enantiomers, are non-superimposable mirror images. D (+) and L (-) enantiomers.
- When equal amounts of D and L forms are present, the resulting mixture is optically inactive and called racemic.
- Monosaccharides can exist in linear and ring forms.
- Linear - Fischer projection, Ring - Haworth Projection.
- For hexoses (6 carbons), the predominant form is the ring structure.
- Six-membered rings are called pyranose, examples are glucose and galactose and five-membered rings are called furanose, example is fructose.
- Chemical properties of monosaccharides include the addition of alcohols to ketones and aldehydes to form hemiacetals (a hemiacetal) or hemiketal
- Hemiacetals/hemiketals are unstable and only present in small amounts in equilibrium mixtures; except when the hydroxyl group is part of the same molecule as the carbonyl group, then a 5 or 6-membered ring can be formed.
- Cyclization yields a and ȣ anomers which can be obtained, and more stable for six member ring.
- Conversion from Fischer to Haworth projection.
- Mutarotation: gradual change in specific rotation in all reducing sugars (except a few ketoses)
- Mutarotation converts between a and ȣ forms.
- a and ß- anomers are typically stable solids in solution, and they quickly equilibrate to an equilibrium mixture of the two forms.
- Example, glucose exists in aqueous solution as a mixture of 36% a- and 64% ß- forms.
- Formation of Glycosides (acetals): Further treatment of a hemiacetal with an alcohol yields an acetal(or ketal)
- The bond from the anomeric carbon to the OR group is called a glycosidic bond or O-glycosidic bond.
- Sugars can be linked by O-glycosidic bonds to form disaccharides and polysaccharides.
- Mutarotation is not possible in a glycoside.
- Glycosides are stable in water and aqueous base.
- Glycosides can be hydrolyzed in aqueous acids yielding an alcohol and a monosaccharide.
- Naming Glycosides – alkyl group bonded to oxygen followed by the name of the carbohydrate then replace ending -e with -ide.
- Reduction of monosaccharides to alditols – the carbonyl group can be reduced to a hydroxyl group by using H2 in the presence of a catalyst and sodium borohydride.
- Reduction of ketones usually produces two diastereoisomeric alditols.
- Examples of naming alditols, drop 'ose' and add 'itol'. D-glucose → D-glucitol (sorbitol)
- Oxidation to aldonic acids – aldehydes in aldoses is oxidized to carboxylic acid by oxidizing agents such as O2 under basic conditions to a carboxylate group, and the carbohydrate is known as a reducing sugar.
- Oxidation to aldaric acids - both ends of the aldose chain are oxidised to carboxylic acids gives aldaric acid.
- Oxidation to uronic acid – An enzyme catalyzed oxidation of the primary alcohol at C-6 of a hexose yields a uronic acid.
- Reduction and oxidation reactions with examples.
- Reducing sugars – monosaccharides with a carbonyl group that oxidizes to give a carboxylic acid; react with Benedict's reagent to give the corresponding carboxylic acid.
- Common monosaccharides – glucose, fructose, galactose.
Disaccharides
- Two sugar molecules linked together by an O-glycosidic bond
- Examples: Sucrose, Lactose, Maltose
- Sucrose – table sugar; glucose and fructose; not a reducing sugar
- Lactose – milk sugar; glucose and galactose; a reducing sugar
- Maltose – malt sugar; two glucose molecules; a reducing sugar
Polysaccharides
- Complex sugars; high molecular weight.
- Can be straight-chain or branched.
- Two main types: homopolysaccharides and heteropolysaccharides.
- Homopolysaccharides produce only one type of monosaccharide on hydrolysis
- Examples of homopolysaccharides include starch, glycogen and cellulose.
- Starch is an important food storage carbohydrate in plants, composed of amylose (straight chain) and amylopectin (branched).
- Glycogen is the storage form of carbohydrates in animals. Structurally similar to amylopectin, but with more branching.
- Cellulose is the most abundant extracellular polysaccharide in plants; structural carbohydrate; glucose units linked by β-1,4-glycosidic linkages.
- Heteropolysaccharides produce more than one type of monosaccharide on hydrolysis.
- Examples of heteropolysaccharides (with biological significance) are hyaluronic acid, chondroitin sulfate, and heparin.
- Hyaluronic acid – found in various tissues; a straight chain polymer of D-glucuronic acid and N-acetyl-D-glucosamine.
- Chondroitin sulfate – found in cartilage and cell coat; straight chain polymer of D-glucuronic acid and N-acetyl-D-galactosamine.
- Heparin – found in the liver; made up of D-glucuronic acid and D-glucosamine-N-sulphate.
- Chitin is a polysaccharide found in the outer skeletons of insects, crabs, shrimps, and lobsters; composed of β (1-4) linked units of the amino sugar N-acetyl-glucosamine; a main source of chitosan.
Oligosaccharides
- 3-10 monosaccharide molecules (same or different)
- Often conjugated to proteins or lipids, functioning as receptors or aiding in cell interaction.
- Found in plants as soluble fiber, may help prevent constipation.
- Examples: Raffinose and Stachyose
- Raffinose – trisaccharide, found in beans, vegetables, and whole grains.
- Stachyose – tetrasaccharide, a normal human metabolite present in human milk and many vegetables.
- Oligosaccharides on blood cells give the groups A, B, O and AB.
- Three types of oligosaccharides are found on the surface of red blood cells, with chains of sugars including N-acetyl galactosamine, N-acetylglucosamine, galactose and L-fucose.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the fundamentals of carbohydrate chemistry, focusing on hexoses, isomerism, and the structural representation of monosaccharides. This quiz covers key concepts like stereochemistry, geometric isomers, and the formation of ring structures in sugars.
