Carbohydrates and Their Structures

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Questions and Answers

What type of glycosidic bonds are present in amylopectin?

β 1 → 6 only

β 1 → 4 only

α 1 → 4 and α 1 → 6 (correct)

α 1 → 6 only

Which structural polysaccharide forms the exoskeletons of insects and crustaceans?

Glycogen

Starch

Chitin (correct)

Cellulose

How many glucose units are linked in an oligosaccharide with a total of 10 glucose units?

10 (correct)

What is the formula for an oligosaccharide composed of 10 glucose units?

C60H102O51 Signup and view all the answers

What is the primary storage polysaccharide in animals?

Glycogen Signup and view all the answers

Which characteristic is NOT true of monosaccharides?

They have a bitter taste. Signup and view all the answers

What type of isomerism do glucose and fructose exhibit?

Structural isomerism Signup and view all the answers

What determines the properties and behavior of carbohydrates?

The glycosidic bond type Signup and view all the answers

Which of the following is a function of oligosaccharides?

Cell-cell recognition Signup and view all the answers

What distinguishes aldose sugars from ketose sugars?

Aldose sugars have a carbonyl group at the terminal position. Signup and view all the answers

How many carbon atoms are present in a hexose sugar?

6 Signup and view all the answers

What is formed when two monosaccharides bond together through a condensation reaction?

Disaccharide Signup and view all the answers

Which of the following statements about glycosidic bonds is incorrect?

Only one type of glycosidic bond exists. Signup and view all the answers

What is the primary reason for the difference between alpha and beta glucose?

The orientation of the OH group on C1. Signup and view all the answers

Which of the following statements about glycosidic bonds is false?

Glycosidic bonds are only found in polysaccharides. Signup and view all the answers

How does the structure of polysaccharides differ from oligosaccharides?

Polysaccharides consist of many monosaccharides. Signup and view all the answers

Which monosaccharide is an example of a pentose?

Ribose Signup and view all the answers

What is the main structural characteristic that distinguishes alpha glucose from beta glucose?

The position of the hydroxyl group on the first carbon Signup and view all the answers

In the context of disaccharide formation, which process connects two monosaccharides?

Dehydration synthesis Signup and view all the answers

What is a characteristic feature of disaccharides?

They are formed by the condensation of two monosaccharides. Signup and view all the answers

What role do enzymes play regarding glycosidic bonds in carbohydrates?

They recognize and specifically break certain types of glycosidic bonds. Signup and view all the answers

Study Notes

Glucose Structure

Glucose can exist in both a long chain and a ring form
The ring form is important for carbohydrate reactions
Alpha glucose: OH group on C1 projects downwards below C1
Beta glucose: OH group on C1 projects upwards above C1

Disaccharides

Formed by condensation reaction between two monosaccharides
Glycosidic bond: covalent bond between two monosaccharides
Glycosidic bond determines the properties and behaviour of carbohydrates
Enzymes are specific for certain glycosidic bonds

Oligosaccharides

Polymers of 3-10 sugar units
Often found on cell membranes attached to proteins and lipids
Function in cell-cell recognition

Polysaccharides

Polymers of many monosaccharides
Can differ in branching and connections between monosaccharides
Function in energy storage and structure

Energy Storage Polysaccharides

Starch: energy storage in plants
- Amylose: unbranched, α 1 → 4 glycosidic bonds
- Amylopectin: branched, α 1 → 4 glycosidic bonds and α 1 → 6 glycosidic bonds
Glycogen: energy storage in animals, highly branched similar to amylopectin

Structural Polysaccharides

Chitin: forms exoskeletons of arthropods and cell walls of fungi
- Polymer of N-acetylglucosamine residues linked by β-1→4 glycosidic bonds
Cellulose: structural component of plant cell walls
- Polymer of glucose monomers linked by β-1→4 glycosidic bonds
Peptidoglycan: forms bacterial cell wall
- Composed of sugar chains cross-linked by peptides

Isomerisation

Isomers have the same molecular formula but different arrangement of atoms
Structural isomerism: different order of atom connections
Stereoisomerism: same structural formula but different spatial arrangement
- Enantiomers: mirror images of each other

Monosaccharides

General characteristics:
- Water soluble
- White, crystalline solids
- Sweet taste
Classification based on:
- Location of carbonyl group:
  - Aldose sugars: terminal group is an aldehyde
  - Ketose sugars: carbonyl group on a non-terminal carbon
- Number of carbons:
  - Triose: 3 carbons
  - Tetrose: 4 carbons
  - Pentose: 5 carbons
  - Hexose: 6 carbons
  - Heptose: 7 carbons

Chemical Formula for Oligosaccharide

The formula for an oligosaccharide containing 10 glucose units is C60H102O51.

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Description

This quiz explores the various structures of carbohydrates, including glucose, disaccharides, oligosaccharides, and polysaccharides. You will learn about glycosidic bonds and the importance of these carbohydrates in energy storage and cell recognition.