This document provides an overview of the plant biochemistry course taught by Salman Saeed at the University College of Management & Sciences in Khanewal, Pakistan. It covers the key topics of carbohydrates, including their classes (monosaccharides, disaccharides, oligosaccharides, polysaccharides), properties, importance for survival, examples (glucose, fructose, galactose, lactose, maltose, sucrose, starch, glycogen, cellulose), and the effects of inadequate carbohydrate intake on the body.

1. Course Title:
Plant Biochemistry
Course Instructor: SALMAN SAEED
Botany department
UNIVERSITY college of management & Sciences, Khanewal,
PAKSITAN

2. Carbohydrates

3. Carbohydrates
Are compounds of tremendous biological and
commercial importance.
o The name Carbohydrates indicates that
they are hydrates of Carbon, and contain
carbon, hydrogen and oxygen.
o Most of them contain hydrogen and
oxygen in the ratio of 2:1.

4. Classes of Carbohydrates
 Monosaccharides composed of one unit of a
polyhydroxy group
 Disaccharides are composed of two units
 Oligosaccharides are composed of 3-10 units
 Polysaccharides are composed of hundreds of
thousands of units.

5. Carbohydrates and functional
groups
 Carbohydrates are polyhydroxy aldehydes
or ketones, or substances that yield such
compounds in hydrolysis.

6. Monosaccharides
contain a single polyhydroxy aldehyde or
ketone unit.
They are the simplest
sugars and cannot be
hydrolyzed into simpler
compounds.
• Their general formula is
CnH2nOn,where n varies
from 3 to7. The most
important are the
pentoses and hexoses

7. CLASSIFICATION OF
CARBOHYDRATES
• The naturally occurring carbohydrates may be classified into three
main groups, particularly on the basis of their behaviour towards
hydrolysis.
• Monosaccharides are classified according to three different
characteristics: the placement of its carbonyl group, the number of
carbon atoms it contains, and its chiral handedness.
• If the carbonyl group is an aldehyde, the monosaccharide is an
aldose; if the carbonyl group is ketone, the monosaccharide is a
ketose. Monosaccharides with three carbon atoms are called
trioses; those with four are called tetroses; five are called
pentoses; six are called hexoses.

8. Disaccharides
 Contain two monosaccharide units attached
together.
• Disaccharides are the most common oligosaccharides found in
nature. Most of the naturally occurring representatives occur in
plants, rather than animal sources.
• The three most important disaccharides found free are sucrose,
lactose, and maltose; a few others are cellobiose and trehalose.
• Based on the type of linkage present in their molecule, the
disaccharides are classified as follows:

9. Disaccharides
Non Reducing Reducing
C1—C1
Glycosidic linkage
Trehalose
C1—C2
Glycosidic linkage
Sucrose
C1—C4
Glycosidic linkage
Lactose
Maltose
Cellobiose
C1—C6
Glycosydic linkage
Gentiobiose
Melibiose
Isomaltose

10. Polysaccharides
 Composed of very long chains of attached
monosaccharides units
Oligosaccharides are less
common

11. Polysaccharides continued
• Polysaccharides represent an important class of biological polymers.
Their function in living organisms is usually either structure or storage
related. Polysaccharides are high molecular weight carbohydrates which
yield a large number of monosaccharides on hydrolysis and are further
classified as:
 Homopolysaccharides
• They contain only a single type of monosaccharide. Some
homopolysaccharides serve as storage forms (starch and
glycogen) and others serve as structural component in plant cell
walls and animals exoskeletons (cellulose and chitin)
 Heteropolysaccharides
• They contain more than one kind of monosaccharide.They are
numerous in both plants and animals, agarose in plants and
hyaluronic acid in animals.

12. Properties of Carbohydrates
 Physical Properties
 They are called sugars
 Taste sweet--- degree varies
 Fructose is the sweetest
 Solid at room temperature
 Soluble in water
solubility helps in carbs to be transported quickly.

13. Why do we need
Carbohydrates to survive?
 To provide the body with energy.
 To help the central nervous system, the kidneys, the
brain, the muscles (including the heart), to function
properly.
 Aids in intestinal health and waste elimination.

14. Carbohydrates

15. Carbohydrates
MONOSACCHARIDES:
• Glucose
• Fructose
• Galactose
DISACCHARIDES:
• Lactose
• Maltose
• Sucrose
POLYSACCHARIDES:
• Starch
• Glycogen
• Cellulose

16. Carbohydrates

17. Without ADEQUATE carbohydrates…??
 Muscle tissue breakdown
 Fatigue
 Brain power diminishes
 Body will go into ketosis
 Nausea
 Mood swings
 Weakness
 Dizziness
 Bad breath
 Depression