Carbohydrates: Disaccharides and Polysaccharides

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Questions and Answers

What constitutes a disaccharide?

Two monosaccharides joined by glycosidic linkage (correct)

Three monosaccharides linked together

One amino acid and one monosaccharide

Two fatty acids linked together

Which of the following disaccharides is classified as a reducing sugar?

Raffinose

Lactose (correct)

Sucrose

Isomaltose (correct)

Which disaccharide is made up of one glucose and one fructose unit?

Sucrose (correct)

Lactose

Galactose

Maltose

What enzyme hydrolyzes lactose into glucose and galactose?

Lactase Signup and view all the answers

Which of the following is a characteristic of non-reducing disaccharides?

Both components in the glycosidic linkage are non-reducing groups Signup and view all the answers

What symptom may indicate lactose intolerance in adults?

Excess gases and bloating Signup and view all the answers

How many monosaccharide units are required to classify a carbohydrate as a polysaccharide?

More than 10 units Signup and view all the answers

What is the result of hydrolyzing sucrose?

Glucose and fructose Signup and view all the answers

Which type of polysaccharide contains only one type of monosaccharide unit?

Homopolysaccharides Signup and view all the answers

What is the storage form of glucose in animal liver and muscles?

Glycogen Signup and view all the answers

Which component of starch forms about 80% of its structure?

Amylopectin Signup and view all the answers

What type of glycosidic bond links glucose residues in cellulose?

β 1-4 Signup and view all the answers

What is a primary difference between amylose and amylopectin?

Amylose is linear, amylopectin is branched. Signup and view all the answers

What type of glucose units does glycogen consist of?

α Glucose Signup and view all the answers

What is the function of cellulose in the human intestine?

It absorbs water and increases stool bulk. Signup and view all the answers

Which polysaccharide serves as the structural component in plants?

Cellulose Signup and view all the answers

Which component of starch is hydrolyzed by amylase to yield maltose and isomaltose units?

Amylopectin Signup and view all the answers

Which type of glucose does cellulose consist of?

b Glucose Signup and view all the answers

What is the primary linkage pattern in glycogen?

Both α 1-4 and α 1-6 linkages Signup and view all the answers

What is the main occurrence site of glycogen in organisms?

In human and animal muscles Signup and view all the answers

What distinguishes amylose from amylopectin in starch?

Amylose is a linear chain while amylopectin contains branching Signup and view all the answers

What is the primary function of hyaluronic acid in the body?

Lubrication and shock absorption Signup and view all the answers

Which of the following GAGs is classified as sulfate-free?

Hyaluronic acid Signup and view all the answers

What role does chondroitin sulfate play in the body?

Helps to maintain cartilage structure Signup and view all the answers

Study Notes

Disaccharides

Definition: Two monosaccharides joined by a glycosidic linkage.
Classification:
- Reducing disaccharides: contain a free anomeric carbon, capable of reducing other compounds. Examples: maltose, isomaltose, lactose.
- Non-reducing disaccharides: do not have a free anomeric carbon. Examples: sucrose.
Maltose: Composed of two glucose units. Hydrolyzed by maltase into two glucose molecules.
Lactose: Composed of one galactose and one glucose unit. Hydrolyzed by lactase into galactose and glucose.
Lactose Intolerance: Some individuals lack lactase, leading to digestive issues after dairy consumption.
Sucrose: Composed of one glucose and one fructose unit. Non-reducing due to involvement of both aldehyde and ketone groups in glycosidic linkage. Hydrolyzed by sucrase into glucose and fructose.

Polysaccharides

Definition: Condensation products of more than 10 monosaccharide units.
Classification:
- Homopolysaccharides: Contain only one type of monosaccharide. Classified by their building units:
  - Glucans: Formed from Glucose units; examples include glycogen, starch, cellulose.
  - Fructans: Formed from Fructose units; example is inulin.
- Heteropolysaccharides: Contain two or more different monosaccharide units.
Glycogen: Storage form of glucose in the liver and muscles of animals. Highly branched structure, with 1,6 branch linkages every 8-10 residues.
Starch: Storage form of glucose in plants. Composed of amylose (linear) and amylopectin (branched) polymers of glucose.
Cellulose: Linear polysaccharide of glucose units linked by β 1,4 glycosidic bonds. Humans cannot digest cellulose due to lack of β amylase. Provides bulk in the digestive system.
Heteropolysaccharides
- Glycosaminoglycans (GAGs): Contain amino sugars. Classified as:
  - Sulfate-free GAGs: Hyaluronic acid
  - Sulfate-containing GAGs: Chondroitin sulfate, Dermatan sulfate, Keratan sulfate, Heparin.
Hyaluronic acid: Lubricant and shock absorbent present in synovial fluid, vitreous humor, and other tissues.
Chondroitin sulfate: Most abundant GAG, present in cartilage, ligaments, and other tissues. Maintains skeletal shape and compressibility of cartilage.
Heparin: Anticoagulant found in mast cells (lung, liver, arterial wall).

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Description

This quiz covers the structure and classification of disaccharides and polysaccharides. Learn about key examples, such as maltose, lactose, and sucrose, along with their hydrolysis processes and relevance in human digestion. Test your understanding of carbohydrate biochemistry.