Carbohydrate Chemistry Quiz
41 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the product of the mild oxidation of glucose when reacted with hydroxylamine?

  • Gluconic acid (correct)
  • Sorbitol
  • Glucaric acid
  • Acetylated glucose

    • What is the final equilibrium specific rotation value reached during the mutarotation of glucose anomers?

  • +112°
  • +19°
  • +52° (correct)
  • +36°

    • What product is formed when glucose is oxidized with a weak oxidizing agent such as bromine water?

  • Glucaric acid
  • Glucosazone
  • Gluconic acid (correct)
  • D-glucitol

    • What compound is formed when glucose undergoes complete acetylation?

    <p>Glucose penta-acetate</p> Signup and view all the answers

    Which reaction occurs when glucose is treated with sodium borohydride?

    <p>Reduction to D-glucitol</p> Signup and view all the answers

    Which of the following describes the reaction products when glucose is reduced?

    <p>Sorbitol and unchanged glucose</p> Signup and view all the answers

    What is the resultant compound when glucose is subjected to vigorous oxidation?

    <p>Glucaric acid</p> Signup and view all the answers

    During the reaction of glucose with phenylhydrazine, which final product is obtained after condensation and oxidation?

    <p>Glucosazone</p> Signup and view all the answers

    What does the change in optical rotation of a glucose solution during mutarotation signify?

    <p>Stabilization at a constant optical rotation</p> Signup and view all the answers

    What is the role of hydroxylamine in the reactions involving glucose?

    <p>It forms an oxime from glucose.</p> Signup and view all the answers

    What is the primary form of storage polysaccharide in animals?

    <p>Glycogen</p> Signup and view all the answers

    Which type of linkage is primarily found in cellulose?

    <p>β (1→4) linkages</p> Signup and view all the answers

    What is the repeating disaccharide unit in cellulose?

    <p>Cellobiose</p> Signup and view all the answers

    What distinguishes amylopectin from amylose?

    <p>Amylopectin contains branches every 20-25 glucose units.</p> Signup and view all the answers

    What happens to amylopectin during hydrolysis?

    <p>It yields maltose.</p> Signup and view all the answers

    What is the molecular formula for heptoses?

    <p>C7H14O7</p> Signup and view all the answers

    Which of the following monosaccharides is classified as a hexose?

    <p>D-glucose</p> Signup and view all the answers

    What characteristic defines the naturally occurring glucose?

    <p>It is D(+) glucose.</p> Signup and view all the answers

    In the Fischer projection for numbering monosaccharides, which carbon is counted as '1' for sugars with a terminal aldehyde function?

    <p>The aldehyde carbon itself</p> Signup and view all the answers

    Which of the following statements is true about glucose?

    <p>Glucose is a white crystalline solid.</p> Signup and view all the answers

    Which of these is NOT an aldohexose?

    <p>D-fructose</p> Signup and view all the answers

    What is the significance of the chiral center at position 5 in D- and L-sugars?

    <p>Determines the stereochemistry of the sugar</p> Signup and view all the answers

    Which of the following correctly identifies the classification of D-galactose?

    <p>It is an aldohexose.</p> Signup and view all the answers

    What is the general formula for carbohydrates?

    <p>Cm(H2O)m</p> Signup and view all the answers

    Which of the following is not a type of carbohydrate?

    <p>Oligonucleotide</p> Signup and view all the answers

    What functional groups are present in carbohydrates?

    <p>Aldehyde group and alcoholic hydroxyl groups</p> Signup and view all the answers

    How are monosaccharides characterized?

    <p>They cannot be broken down into simpler carbohydrates upon hydrolysis.</p> Signup and view all the answers

    Which of the following is an example of a trisaccharide?

    <p>Raffinose</p> Signup and view all the answers

    What is the classification of carbohydrates based on the number of sugar units?

    <p>Monosaccharides, oligosaccharides, polysaccharides</p> Signup and view all the answers

    Which is the correct reaction for the hydrolysis of sucrose?

    <p>C12H22O11 + H2O → 2 C6H12O6</p> Signup and view all the answers

    Which of the following statements about polysaccharides is true?

    <p>They are made of more than ten monosaccharide units.</p> Signup and view all the answers

    What direction does fructose rotate in a polarimeter?

    <p>Left</p> Signup and view all the answers

    Which of the following is a stable form of D-fructose?

    <p>a-D-Fructopyranose</p> Signup and view all the answers

    Which reaction does fructose undergo upon vigorous oxidation?

    <p>Formation of glycaric acid</p> Signup and view all the answers

    Which linkage types are possible in glycogen?

    <p>α(1→4) and α(1→6)</p> Signup and view all the answers

    In the reactions of fructose, which product is formed from its reduction?

    <p>Mannitol</p> Signup and view all the answers

    Which structural form represents the ring isomer of b-D-fructose?

    <p>Furanose</p> Signup and view all the answers

    What is the result of the acetylation of fructose?

    <p>Creation of fructose acetates</p> Signup and view all the answers

    What is an incorrect statement about α-D-fructopyranose?

    <p>It can undergo oxidation to glucuronic acid.</p> Signup and view all the answers

    Which fragment is not part of the structure of D-fructose?

    <p>COOH</p> Signup and view all the answers

    Which of the following is true regarding the formation of glycosidic bonds?

    <p>Glycosidic bonds are formed by elimination of water.</p> Signup and view all the answers

    Study Notes

    Carbohydrate Introduction

    • Carbohydrates are polyhydroxy aldehydes or polyhydroxy ketones
    • They are large molecules that form compounds through hydrolysis
    • They are a vital class of naturally occurring organic compounds
    • Examples of carbohydrates include glucose (grapes), fructose (honey), starch (potatoes), and cellulose (wood)
    • Carbohydrates are composed of carbon (C), hydrogen (H), and oxygen (O)
    • The general formula for carbohydrates is Cm(H2O)m
    • Carbohydrates are often called saccharides
    • Carbohydrates are polyfunctional compounds containing alcoholic hydroxyl groups, aldehyde groups, and ketone groups

    Classification of Carbohydrates

    • Carbohydrates are categorized into three groups based on the number of simple sugars produced by hydrolysis
      1. Monosaccharides: These are single-unit carbohydrates that cannot be broken down into simpler carbohydrates through hydrolysis. Examples include glucose and fructose (C6H12O6)
      1. Oligosaccharides: These contain 2 to 10 monosaccharide units. Disaccharides (e.g., sucrose) contain two monosaccharides, and trisaccharides (e.g., raffinose) contain three.
      • Sucrose → glucose + fructose
      • Raffinose → C6H12O6 + C6H12O6 + C6H12O6
      1. Polysaccharides: These contain more than 10 monosaccharide units. A single molecule of starch or cellulose can form a very large number of glucose units through hydrolysis.
      • Starch: made from amylose & amylopectin
      • Glycogen: branched polymer of glucose; used for energy storage in animals
      • Cellulose: linear polymer of glucose; used as structural material in plant cell walls

    Monosaccharides

    • Monosaccharides are the simplest form of carbohydrates.
    • They have the general formula CnH2nOn, where n ranges from 3 to 8.
    • Different names are given based on the number of carbons in the molecule (trioses, tetroses, pentoses, hexoses, heptoses, octoses)
    • Examples include glyceraldehyde, erythrose, ribose, glucose, and heptulose
    • The most common monosaccharides are pentoses and hexoses
    • Glucose and fructose are amongst the most important and typical hexoses

    Glucose

    • Glucose is the most common monosaccharide
    • Also known as dextrose, it's a dextrorotatory isomer
    • The naturally occurring glucose is D(+) glucose and fructose is D(-) fructose (optical isomers).
    • It's a pentahydroxyhexanal
    • It is a vital component of human blood.
    • Normal blood glucose levels are 65-110 mg/dL
    • In diabetic patients, glucose levels increase
    • It exists as a solid, soluble in water, sparingly soluble in ethanol, and is optically active

    Physical Properties of Glucose

    • Glucose is a white crystalline solid
    • Melting point (M.P.) is 146°C
    • It's soluble in water and sparingly soluble in ethanol
    • It exhibits optical activity

    Naming Simple Monosaccharides

    • Monosaccharides have functional groups like aldehyde or a ketone
    • Chiral centers have a set configuration; changing the configuration will yield a different sugar

    Aldohexoses

    • Examples of aldohexoses include D-allose, D-altrose, D-glucose, D-mannose, D-idose, D-galactose, and D-talose.

    Numbering Monosaccharides

    • In the Fischer projection, the aldehyde group is placed at the top, and the carbon atoms are numbered sequentially.
    • For keto sugars, the keto group is placed second from the top

    Projections for representing Glucose

    • Haworth projection
    • Cyclohexane projection
    • Fischer projection

    Carbohydrate Structure

    • D-sugars have the hydroxyl group on the rightmost chiral carbon
    • L-sugars have the hydroxyl group on the leftmost chiral carbon

    Acetal and Ketal Formation

    • Ketones and alcohols react to form hemiacetals and ketals.
    • The resulting product is an acetal

    Ring Formation in Monosaccharides

    • The -OH group on C5 reacts with C1 to form a 6-membered ring (pyranose).
    • The resulting ring is relatively unstrained

    Specific Rotation

    • Specific rotations of α and β anomers decrease or increase to a stable equilibrium.
    • The process of change in optical rotation is called mutarotation

    Monosaccharide Anomers

    • The anomeric carbon is the carbon that was involved in the hemiacetal/ketal formation.

    Chemical Properties of Glucose

    • Oxidation: Oxidation with a weak oxidizing agent (bromine water) yields gluconic acid. Oxidation with a strong oxidizing agent (nitric acid) yields glucaric acid.
    • Reduction: Reduction with sodium borohydride gives glucitol (sorbitol).
    • Acetylation: Reaction with acetic anhydride in the presence of anhydrous zinc chloride forms penta-acetyl glucose.
    • Reaction with hydroxylamine: Forms glucose oxime
    • Reaction with phenylhydrazine: Forms glucosazone

    Chemical Properties of Fructose (Ketose)

    • Oxidation similar to glucose but with more complex results
    • Reduction similar to glucose, producing sorbitol or mannitol
    • Acetylation, hydroxylamine, and phenylhydrazine reactions are also possible.

    Glycosidic Bond

    • A bond formed between a hemiacetal/ketal functional group of a carbohydrate and another molecule.
      • Methyl-α or -β-D-glucopyranoside as an example

    Disaccharides

    • Sucrose, Lactose, and Maltose are examples

    Polysaccharides

    • Starch, Glycogen, and Cellulose are examples

    Glycogen

    • Major storage form of glucose in animals
    • Highly branched
    • Linear linkages (α-1,4), branch linkages (α-1,6)

    Cellulose

    • Found in plants cell walls
    • Linear polymer of glucose
    • α(1-4) linkages
    • Hydrogen bonding creates strength

    Starch

    • Composed of amylose and amylopectin
    • Amylose: α(1→4) linkages
    • Amylopectin: α(1→4) linkages; α(1→6) branch points

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Carbohydrates Introduction Lecture Notes PDF

    Description

    Test your knowledge on the chemical reactions involving glucose, including oxidation, reduction, and mutarotation. This quiz covers various products formed through different chemical processes, including reactions with hydroxylamine and sodium borohydride. Perfect for students studying carbohydrate chemistry or biochemistry.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser