Slide 1

Biomolecules - Structural Formulas for Monosaccharides

Monosaccharides are the simplest form of carbohydrates
They are classified based on the number of carbon atoms they contain
The structural formula represents the arrangement of atoms in a molecule

Slide 2

Monosaccharides - Trioses

Trioses have three carbon atoms
Example: glyceraldehyde (an aldotriose)
```
CHO
|
C=O
|
CH2OH
```
The structure is asymmetric with a chiral carbon atom

Slide 3

Monosaccharides - Tetroses

Tetroses have four carbon atoms
Example: erythrose (an aldotetrose)
```
CHO
|
CHO
|
CH2OH
```
The structure is also asymmetric

Slide 4

Monosaccharides - Pentoses

Pentoses have five carbon atoms
Example: ribose (an aldopentose)
```
CHO
|
CHOH
|
CH2OH
```
Another example is deoxyribose (found in DNA)

Slide 5

Monosaccharides - Hexoses

Hexoses have six carbon atoms
Example: glucose (an aldohexose)
```
CHO
|
C=O
|
CHOH
|
CH2OH
```
Glucose is the most abundant monosaccharide in nature and is an important source of energy

Slide 6

Monosaccharides - Hexoses (contd.)

Another example is fructose (a ketohexose)

    |
CH2OH
    |
C=O
    |
    CHOH
    |
    CH2OH

Fructose is found in fruits and is often used as a sweetener

Slide 7

Monosaccharides - Heptoses

Heptoses have seven carbon atoms

Example: sedoheptulose (an ketose)

    |
CH2OH
    |
C=O
    |
CHOH
    |
C=O
    |
CHOH
    |
    CH2OH

Heptoses are less commonly found in nature compared to other monosaccharides

Slide 8

Monosaccharides - Isomers

Isomers are molecules with the same molecular formula but different structural arrangements
Monosaccharides can exist as multiple isomers
Example: glucose and fructose are isomers of each other

Slide 9

Monosaccharides - Enantiomers

Enantiomers are mirror images of each other
Monosaccharides can form enantiomers due to the presence of chiral carbon atoms
Example: D-glucose and L-glucose

Slide 10

Monosaccharides - Ring Structures

Monosaccharides can undergo ring formation in aqueous solutions
The ring structure is more stable due to the formation of a hemiacetal or hemiketal
Example: glucose can exist as both a linear and a ring structure

Monosaccharides - Ring Structures (continued)

Glucose forms a ring structure called a pyranose ring

The ring is formed by the reaction between the aldehyde group (C=O) and a hydroxyl group (OH) on the same molecule

   OH         OH
   |          |
HO-C-H     HO-C-H
   |          |
|    |       |    |
C-O  |    C-O  |
|    |       |    |
CH2OH      H2

The ring structure results in the formation of an additional chiral carbon atom

Monosaccharides - Haworth Projection

The ring structure of monosaccharides can be represented using a Haworth projection
In a Haworth projection, the molecule is depicted as a planar polygon with the ring atoms and functional groups shown

Example: Haworth projection of glucose

     OH
     |
HO-C-H
     |
O    CH2OH

Monosaccharides - Anomers

Anomers are cyclic monosaccharides that differ only in the configuration at the anomeric carbon (the carbon involved in ring formation)
The anomeric carbon can have two different configurations: alpha and beta
The alpha anomer has the hydroxyl group (OH) on the opposite side of the ring compared to the CH2OH group
The beta anomer has the hydroxyl group (OH) on the same side of the ring as the CH2OH group
Example: alpha-D-glucose and beta-D-glucose

Monosaccharides - Glycosidic Bond

Monosaccharides can undergo a condensation reaction to form disaccharides or polysaccharides
The condensation reaction involves the loss of a water molecule and the formation of a glycosidic bond between the anomeric carbon of one monosaccharide and a hydroxyl group of another monosaccharide
Example: formation of a glycosidic bond between two glucose molecules to form maltose

Monosaccharides - Disaccharides

Disaccharides are formed by the combination of two monosaccharides through a glycosidic bond
Examples of disaccharides include maltose (glucose + glucose), sucrose (glucose + fructose), and lactose (glucose + galactose)
Disaccharides serve as a source of energy and are commonly found in foods such as sugar, honey, and milk

Monosaccharides - Polysaccharides

Polysaccharides are long chains of monosaccharides that can be branched or unbranched
They have various functions, including energy storage and structural support
Examples of polysaccharides include starch (energy storage in plants), glycogen (energy storage in animals), and cellulose (structural component in plants)

Monosaccharides - Starch

Starch is a polysaccharide composed of glucose units
It serves as an energy storage molecule in plants
Starch can be separated into two components: amylose (unbranched) and amylopectin (branched)
Amylose consists of a linear chain of glucose molecules joined by alpha glycosidic bonds
Amylopectin has a branched structure with alpha glycosidic bonds and additional branches formed by alpha-1,6-glycosidic bonds

Monosaccharides - Glycogen

Glycogen is a polysaccharide composed of glucose units
It serves as an energy storage molecule in animals, particularly in the liver and muscles
Glycogen has a highly branched structure, allowing for quick release of glucose when needed
The alpha-1,4-glycosidic bonds form the linear segments, and the alpha-1,6-glycosidic bonds form the branches

Monosaccharides - Cellulose

Cellulose is a polysaccharide composed of glucose units
It serves as a structural component in plant cell walls
Cellulose has a linear structure where the glucose molecules are joined by beta-1,4-glycosidic bonds
The beta configuration of the glycosidic bond allows for the formation of strong hydrogen bonds between adjacent cellulose molecules, creating a rigid structure

Summary and Key Points

Monosaccharides are the simplest form of carbohydrates, classified based on the number of carbon atoms they contain
Monosaccharides can exist in different structural forms, including linear and ring structures
Ring structures are more stable and can undergo further reactions to form disaccharides and polysaccharides
Disaccharides include maltose, sucrose, and lactose, while polysaccharides include starch, glycogen, and cellulose
Each polysaccharide has a specific function and unique structural characteristics Sure! Here are slides 21 to 30 for your lecture on “Biomolecules - Structural Formulas for Monosaccharides”:

Slide 21

Carbohydrates - Functions

Carbohydrates serve as an important source of energy in living organisms
They are involved in cell signaling and communication
Carbohydrates play a key role in DNA and RNA synthesis
They are essential for building cell walls and providing structural support
Carbohydrates also contribute to the immune system and blood clotting

Slide 22

Carbohydrates - Classification

Carbohydrates can be classified into three main groups: monosaccharides, disaccharides, and polysaccharides
Monosaccharides are the simplest units of carbohydrates, while disaccharides and polysaccharides are formed by the combination of monosaccharides
The complexity of the carbohydrate increases with the number of monosaccharide units

Slide 23

Monosaccharides - Importance

Monosaccharides are the building blocks of carbohydrates
They are essential for energy production in cells
Monosaccharides are involved in cell recognition and signaling processes
They serve as precursors for the synthesis of other biomolecules, such as amino acids and lipids

Slide 24

Monosaccharides - Chemical Formula

Monosaccharides have the general chemical formula (CH2O)n, where n is the number of carbon atoms
The carbon atoms in a monosaccharide are typically numbered for reference

Slide 25

Monosaccharides - Stereoisomerism

Monosaccharides exhibit stereoisomerism due to the presence of chiral carbon atoms
Chiral carbon atoms have four different groups attached to them
Enantiomers and diastereomers are two types of stereoisomers
Enantiomers are mirror images of each other, while diastereomers have different spatial arrangements

Slide 26

Monosaccharides - Fischer Projection

Fischer projection is a method to represent the chiral structure of monosaccharides
In a Fischer projection, vertical lines represent bonds extending towards the viewer, and horizontal lines represent bonds extending away from the viewer
The lowest numbered chiral carbon is usually placed at the top in a Fischer projection

Slide 27

Monosaccharides - D and L Configuration

Monosaccharides can exist in D or L configurations based on the arrangement of hydroxyl groups around the chiral carbon furthest from the carbonyl group
D-configurations have the -OH group on the right side, while L-configurations have the -OH group on the left side
D-glucose and D-ribose are common examples of D-configurations

Slide 28

Monosaccharides - Haworth Projection (example)

Haworth projection is another method to represent the cyclic structure of monosaccharides
In a Haworth projection, the ring is represented by a planar polygon, with the anomeric carbon at the top
The positions of the substituents are indicated by their positions relative to the ring

Slide 29

Monosaccharides - Anomeric Carbon

The anomeric carbon is the carbon that becomes chiral in the formation of the cyclic structure of monosaccharides
The anomeric carbon is typically labeled with an asterisk (*) in a Haworth projection
It is involved in the formation of glycosidic bonds in disaccharides and polysaccharides

Slide 30

Monosaccharides - Summary

Monosaccharides are the simplest units of carbohydrates
They have the general formula (CH2O)n, where n is the number of carbon atoms
Monosaccharides exhibit stereoisomerism, with D and L configurations
Fischer projection and Haworth projection are used to represent the structure of monosaccharides
The anomeric carbon plays a crucial role in the formation of glycosidic bonds

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