This document discusses carbohydrates and classifies them into three categories: monosaccharides, disaccharides, and polysaccharides. Monosaccharides are simple sugars that serve as building blocks. Disaccharides are formed when two monosaccharides bond together. Polysaccharides are complex carbohydrates formed from chains of many monosaccharides bonded together. Carbohydrates provide energy, energy storage, and structural support in organisms. Their general formula is CH2O.
4. Objectives
• To understand the classification of
1 carbohydrates
• To become familiar with steroisomerism
2
• To draw the structures of and to
3 indicate the reactions of several hexoses
• To compare the structures and reactions
4 of disaccharides and polysaccharides
5. Carbohydrates
• All carbohydrates are composed of
carbon, hydrogen, and oxygen in a
1:2:1 empirical ratio.
• The general empirical formula for a
carbohydrate is CH2O.
If a carbohydrate has 5 carbons
atoms, what would be its empirical
formula? C5H10O5
If a carbohydrate has 12
hydrogen atoms present, what
would be its empirical formula?
C6H12O6
• Most carbohydrates end with the suffix -ose
6. Functions of Carbohydrates
• Provide energy source: A fuel source when
catabolized during cellular respiration. Energy is
stored in the chemical bonds within the molecule
and released during cellular respiration. Usually
simple sugars.
• Provide energy storage: Plants store energy in a
complex carbohydrate form called starch
(amylose). Animals store energy in a complex
carbohydrate in their muscle tissue and liver in
the called glycogen.
• Structural Building Material: Plants build their cell
walls of a complex carbohydrate material called
cellulose. Animals such as arthropods build their
exoskeletons of a complex carbohydrate called
chitin. Chitin is also found in the cell walls of
7. Classes of Carbohydrates
• There are three major classes of carbohydrates:
1. Monosaccharides (simple sugars) These
are the monomers or building blocks for all other
classes of carbohydrates. Examples: glucose,
fructose, galactose, and ribose.
2. Disaccharides are produced by joining
two simple sugars by dehydration synthesis
forming a covalent bond between them.
Examples: sucrose (table sugar), maltose,
lactose
3. Polysaccharides (complex
carbohydrates) are produced by joining many
monosaccharides together by many dehydration
synthesis reactions forming a polymer molecule.
Examples: amylose, glycogen, cellulose, and
chitin
13. Carbohydrates
Carbohydrates (or saccharides) consist of only
carbon, hydrogen and oxygen
Carbohydrates come primarily from
plants, however animals can also biosynthesize
them
The “Carbon Cycle” describes the processes by
which carbon is recycled on our planet
- Energy from the sun is stored in plants, which
use photosynthesis to convert carbon dioxide and
water to glucose and oxygen
- In the reverse process, energy is produced
when animals oxidize glucose during respiration
Photosynthesis
6CO2 + 6H2O + Energy C6H12O6 + 6O2
Respiration