Polysaccharides Overview
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Questions and Answers

What is the primary function of polysaccharides in the body?

  • To facilitate communication between cells
  • To act as enzymes
  • To transport oxygen in the blood
  • To provide structural materials and energy (correct)

Which type of amylase is found in saliva and pancreatic juice?

  • β-amylase
  • γ-amylase
  • δ-amylase
  • α-amylase (correct)

What type of linkage is present in amylose?

  • β-1,4 glycosidic bonds
  • α-1,4 glycosidic bonds (correct)
  • γ-1,5 glycosidic bonds
  • α-1,6 glycosidic bonds

What distinguishes amylopectin from amylose?

<p>Amylopectin is branched and has α-1,6 linkages (D)</p> Signup and view all the answers

Why are starches considered convenient storage materials?

<p>They are easily hydrolyzed to sugars (C)</p> Signup and view all the answers

What is a characteristic of pure starch?

<p>It is a white, tasteless, and odorless powder (B)</p> Signup and view all the answers

Which of the following occurs during the hydrolysis of starch?

<p>Hydrolysis of α-glycosidic linkage (A)</p> Signup and view all the answers

In which structures is starch primarily stored?

<p>Chloroplasts and storage organs (A)</p> Signup and view all the answers

What structural feature distinguishes inulin from starch?

<p>Presence of β-(1,2) linked fructofuranoses (D)</p> Signup and view all the answers

Which of the following correctly describes the action of dietary fiber in the body?

<p>Increases the bulk of stools and facilitates passage through the colon (C)</p> Signup and view all the answers

What is a defining characteristic of glycosaminoglycans?

<p>They are linear polymers made of disaccharides that often contain N-acetylglucosamine (A)</p> Signup and view all the answers

Which of the following statements about mucopolysaccharidoses is true?

<p>They are genetic disorders related to proteoglycan metabolism (B)</p> Signup and view all the answers

Which compound is indicated by a blue color reaction when iodine is applied?

<p>Starch (A)</p> Signup and view all the answers

What is the role of proteoglycans in the body?

<p>They function as conjugated proteins linking core proteins to glycosaminoglycans (D)</p> Signup and view all the answers

What type of bonds link D-glucose units in glycogen?

<p>α-1,4 and α-1,6 glycosidic bonds (C)</p> Signup and view all the answers

Which of the following is a potential consequence of consuming too much dietary fiber?

<p>Increased risk of diarrhea (C)</p> Signup and view all the answers

What structural characteristic differentiates amylopectin from amylose?

<p>Amylopectin contains both α-1,4 and α-1,6 linkages. (B)</p> Signup and view all the answers

What is the primary molecular interaction that allows starch to function as a storage material?

<p>Its capacity to be easily hydrolyzed into sugars. (A)</p> Signup and view all the answers

Which type of linkage does NOT occur in amylose?

<p>α-1,6 linkages. (C)</p> Signup and view all the answers

Which statement accurately describes α-amylase?

<p>It is present in both saliva and pancreatic juice. (C)</p> Signup and view all the answers

What is a defining characteristic of the pure starch composition?

<p>It is white, tasteless, and odorless. (C)</p> Signup and view all the answers

Which condition is associated with polysaccharide metabolism issues?

<p>Skeletal deformities. (B)</p> Signup and view all the answers

What is the primary function of polysaccharides in biological systems?

<p>To provide structural integrity. (A)</p> Signup and view all the answers

What type of amylase exists in sprouted grains and malts?

<p>Beta-amylase. (D)</p> Signup and view all the answers

Which characteristic relates to the hydrolysis of starch?

<p>Amylases hydrolyze starch into simple sugars. (C)</p> Signup and view all the answers

What role does amylose play in starch’s overall structure?

<p>It provides a straight chain component to the starch. (C)</p> Signup and view all the answers

What is the primary structural feature of inulin?

<p>Linear with β-(1,2) linked fructofuranoses (B)</p> Signup and view all the answers

Which statement accurately describes the molecular weight of inulin compared to starch?

<p>Inulin has a lower molecular weight than starch (A)</p> Signup and view all the answers

How do glycosaminoglycans primarily differ from homopolysaccharides?

<p>Glycosaminoglycans are linear polymers of disaccharides (D)</p> Signup and view all the answers

What is the consequence of a deficiency in lysosomal enzymes related to mucopolysaccharides?

<p>Accumulation of glycosaminoglycans in the body (A)</p> Signup and view all the answers

What causes the yellow color reaction of inulin when iodine is applied?

<p>Structure of fructofuranoses (A)</p> Signup and view all the answers

What roles do dietary fibers mostly fulfill in the digestive system?

<p>Increase stool bulk and reduce cholesterol absorption (D)</p> Signup and view all the answers

Which compound produces a violet color reaction when iodine is applied?

<p>Glycogen (D)</p> Signup and view all the answers

What are proteoglycans primarily composed of?

<p>Core proteins linked to glycosaminoglycans (D)</p> Signup and view all the answers

What defines the structure of starch as a polysaccharide?

<p>Branched chains of D-glucose with α-1,4 and α-1,6 linkages (B)</p> Signup and view all the answers

Which characteristics distinguish mucopolysaccharidoses as genetic disorders?

<p>They result from mutations affecting glycosaminoglycan metabolism (B)</p> Signup and view all the answers

Flashcards

Polysaccharides

Large, complex carbohydrates made of many simple sugar units. They are insoluble and high molecular weight.

Starch Structure

A storage polysaccharide in plants, composed of amylose (linear) and amylopectin (branched) chains of glucose.

Amylose

A linear chain of glucose molecules linked by α(1→4) glycosidic bonds in starch.

Amylopectin

A branched chain of glucose molecules linked by α(1→4) and α(1→6) glycosidic bonds in starch.

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α-amylase

An enzyme that breaks down starch by hydrolyzing α(1→4) glycosidic bonds.

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β-amylase

An enzyme that breaks down starch by hydrolyzing α(1→4) glycosidic bonds, found in sprouted grains and malts.

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Starch Function

Starch serves as a storage form of energy for plants, stored in chloroplasts and storage organs, such as seeds.

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Hydrolysis of Starch

The process of breaking down starch into simpler sugars (like glucose) using enzymes like amylase.

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Glycogen structure

A branched polysaccharide composed of D-glucose units linked by α-1,4 and α-1,6 glycosidic bonds. Branching occurs every 8-10 residues.

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Amylose vs. Amylopectin

Amylose is a linear polysaccharide of glucose, while amylopectin is branched. Starch is composed of both.

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Inulin structure

A linear polysaccharide of fructose linked by β-(1,2) bonds.

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Dietary fiber function

Increases stool bulk, facilitates colon passage, prevents constipation, and can decrease blood cholesterol absorption.

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Proteoglycans

Proteins linked to glycosaminoglycans, forming large complexes.

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Mucopolysaccharidoses (MPS)

Genetic disorders resulting from a deficiency in lysosomal enzymes needed to break down glycosaminoglycans. This leads to their accumulation.

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Glycosaminoglycans (GAGs)

Linear polysaccharides composed of repeating disaccharides containing amino sugars.

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Storage Polysaccharides

Polysaccharides used for energy storage in living organisms.

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What are polysaccharides?

Large, complex carbohydrates made up of many simple sugar units linked together. They are insoluble in water and have a high molecular weight.

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What are the main functions of polysaccharides?

They play a crucial role in energy storage for organisms and provide structural support for cells and tissues.

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Starch

A storage polysaccharide found in plants, made up of two types of glucose chains: amylose (linear) and amylopectin (branched).

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What are amylases?

Enzymes that break down starch into smaller sugar molecules by hydrolyzing the glycosidic bonds.

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Glycogen

A branched polysaccharide of glucose units, used for energy storage in animals.

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How is starch broken down?

Starch is broken down by enzymes called amylases, which hydrolyze the glycosidic bonds between glucose units, releasing simple sugars like glucose for energy.

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Inulin

A storage polysaccharide in some plants, consisting of fructose units linked in a linear chain.

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Dietary Fiber

Plant-based carbohydrates that aren't digestible by humans. They have various health benefits.

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What is the function of dietary fiber?

Dietary fiber helps promote regular bowel movements by adding bulk, lowers blood cholesterol, and may reduce the risk of colon cancer.

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What are Mucopolysaccharidoses (MPS)?

A group of genetic disorders where there's a deficiency of enzymes needed to break down glycosaminoglycans. This leads to their buildup and can cause various health issues.

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What is the difference between starch and glycogen?

Both are storage polysaccharides made of glucose, but starch is found in plants while glycogen is found in animals. Glycogen is more highly branched than starch.

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What are the bonds in starch?

Starch has two types of glycosidic bonds: α(1→4) bonds in both amylose and amylopectin, and α(1→6) bonds only in amylopectin.

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Study Notes

Polysaccharides

  • Polysaccharides are high molecular weight carbohydrates
  • They are insoluble and non-sugars
  • On hydrolysis, they yield monosaccharides or products related to them
  • They are polymeric anhydrides of simple sugars
  • D-glucose is a common component
  • Examples of other components include: D- and L-galactose, D-mannose, D-xylose, L-arabinose, D-glucoronic, D-galacturonic, D-mannuronic acids, D-glucoseamine, D-galactoseamine, and aminouronic acids
  • Polysaccharides differ from each other based on molecular weight, chain nature (linear or branched), and type of glycosidic bonds (α or β)

Types of Polysaccharides

  • Homopolysaccharides: Hydrolyze to yield a single monosaccharide
    • Storage polysaccharides: starch, glycogen, inulin
    • Structural polysaccharides: cellulose, pectin, chitin
  • Heteropolysaccharides: Hydrolyze to yield a mixture of monosaccharides
    • Glycosaminoglycans (e.g., hyaluronic acid, chondroitin sulfates A and C, dermatan sulfate): Structural components of connective tissues and mucous substances

Functions of Polysaccharides

  • Energy storage: Starch (plants), glycogen (animals)
  • Structural support: Cellulose (plant cell walls), chitin (exoskeletons)
  • Polysaccharides are also used in industry for various applications including water treatment, pulp and paper, biomedical applications, cosmetics, biotechnology and agriculture

Starch

  • A polymer of α-glucose
  • Stored as granules in chloroplasts and storage organs of plants (e.g., potatoes, seeds)
  • Two types of molecules: amylose (linear and helical) and amylopectin (branched)
  • Amylases (α-amylase and β-amylase) are present in saliva and pancreatic juice; they hydrolyze α-glycosidic linkages, making starch easier to digest as sugars

Glycogen

  • A polymer of α-glucose
  • An animal storage polysaccharide, stored in liver and muscle
  • More branched than starch, with branching after 8-10 residues, making it easily mobilized
  • More compact form of energy storage compared to starch

Inulin

  • Storage polysaccharide of the Compositae family (e.g., tubers of dahlia, artichoke, roots of dandelion)
  • Lower molecular weight than starch
  • Polymer of D-fructose, β-(1,2) linked fructofuranoses
  • Linear, no branching
  • Colors yellow with iodine
  • Yields fructose on hydrolysis

Cellulose

  • A structural polysaccharide in plant cell walls
  • Polymer of β-D-glucose
  • Linear, no branching
  • Insoluble in water and lacks sweetness
  • Provides structural support to plant cells
  • Humans cannot digest cellulose due to the lack of an enzyme to break down β-glycosidic bonds

Pectin

  • A structural component found in the middle lamella between cell walls and in ripe fruits (e.g., guava, apples, pears)
  • A high molecular weight polysaccharide
  • Chemically, it's a polysaccharide of α-D-galacturonic acid, with some carboxyl groups esterified with methyl alcohol or combined with calcium or magnesium ions.
  • It has gelling properties and is used in the food industry as a thickener and gelling agent.

Chitin

  • A structural polysaccharide found in fungi and exoskeletons of arthropods (e.g., crabs, insects)
  • It is a polymer of N-acetyl-β-D-glucosamine
  • It has excellent mechanical properties, providing support to the exoskeleton

Glycosaminoglycans (GAGs)

  • Heteropolysaccharides
  • Composed of repeating disaccharide units with an amino sugar and uronic acid
  • Important components of connective tissues and play a role in lubrication

Hyaluronic acid

  • Most abundant GAG
  • Important component of synovial fluid (lubricant), vitreous body of the eye, and umbilical cord
  • Straight-chain polymer of D-glucuronic acid and N-acetyl-D-glucosamine.

Chondroitin Sulfates

  • Widely distributed in cartilage, tendons, and bones
  • Essential for structural support in these tissues
  • Formed from disaccharide units with D-glucuronic acid and N-acetyl-D-galactosamine, with sulfate groups

Dermatan Sulfate

  • A sulfated mucopolysaccharide similar to chondroitin sulfate A, but has L-iduronic acid instead of D-glucuronic acid

Heparin

  • An anticoagulant and found in liver, lung, and arterial walls
  • It inhibits blood clotting by interfering with the conversion of prothrombin to thrombin

Proteoglycans

  • Proteins conjugated with glycosaminoglycans (GAGs)
  • Important structural components of connective tissues

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Polysaccharides Lecture Notes PDF

Description

Explore the fascinating world of polysaccharides, high molecular weight carbohydrates that play essential roles in biology. This quiz covers their types, structures, and hydrolysis products, including homopolysaccharides like starch and heteropolysaccharides like glycosaminoglycans. Test your knowledge on the various components and characteristics of these vital macromolecules.

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