1. Carbohydrates

2. Carbohydrates-sugars
Made of C, H,O
Carb = Carbon hydr = water Carbohydrate = carbon + water
general formula = CH2O 2-1 ratio of hydrogen to oxygen like water H2O
ribose C5H10O5
glucose C6H12O6
sucrose C12H22O11
many carbohydrate names end in -ose

3. More carbohydrate basics
Monomer: monosaccharide – one sugar
Functions of carbohydrates:
Energy for metabolism (glucose)
Short term energy storage (glycogen/starch)
Structure: plants – cell wall animals – exoskeleton
Source of carbon for other molecules
Cell surface markers – cell identification

4. Monosaccharide: Simple Sugars
Monossaccharides like glucose are the main source of energy in living things

5. Modified Monosaccharides
Some monosaccharides have functional groups attached to them – give them special functions
Activated form involved in Becomes part of proteins The monomer of chitin - the
freeing energy from glucose which hold tissue together functional group provides
additional sites for H bonding between chitin molecules

6. Disaccharides-2 sugars
2 monosaccharides linked together by a condensation reaction
- form a glycosidic bond
Examples:
Sucrose – Table Sugar
glucose + fructose
Lactose – Milk Sugar
glucose + galactose
Maltose –
glucose + glucose

7. Polysaccharides-Many Sugars
Polysaccharides are polymers composed of large numbers of monosaccharides.
- the monosaccharides are joined by condensation reactions.
- form glycosidic bonds
Used for short term
energy storage and
structure

8. Energy Storage Polysaccharides
Starch
polymer made up of glucose monomers
Stores glucose in plants
Chloroplast
Starch
1 m
Starch: a plant polysaccharide

9. Glycogen: an animal polysaccharide
Polymer of glucose monomers
Is the major storage form of glucose in animals
Stored in liver and muscle
More highly branched than
starch – contains more
stored energy
Mitochondria
Glycogen granules
0.5 m
Glycogen: an animal polysaccharide
Glycogen

10. Starch and Glycogen are Easily Broken Apart by Hydrolysis
Allows the stored glucose to be easily used

11. Structural Polysaccharides
Cellulose
Is a polymer of glucose – connected in a straight unbranched chain
Multiple strands of cellulose are held together by hydrogen bonds – makes a rigid structure
Is a major component of the tough walls that enclose plant cells

12.  Figure 5.8 About 80 cellulose molecules associate
Plant cells
0.5 m
Cell walls
Cellulose microfibrils
in a plant cell wall 
Microfibril
CH2OH OH O
Glucose monomer
Parallel cellulose molecules are
held together by hydrogen
bonds between hydroxyl
groups attached to carbon
atoms 3 and 6.
About 80 cellulose
molecules associate
to form a microfibril, the
main architectural unit
of the plant cell wall.
A cellulose molecule
is an unbranched 
glucose polymer.
Cellulose
molecules
Figure 5.8

13. Cellulose and starch are both polymers of glucose,
but the bonds which hold them together are different
The difference in bonds creates differences in the molecules

14. Cellulose is difficult to digest
Animals can’t break the bonds between the glucose molecules –dietary fiber
Animals that eat plants have bacteria in their stomachs that can break the bonds of cellulose- allow their hosts to digest plants
Figure 5.9

15. Chitin, another important structural polysaccharide
Is a polymer of a form of glucose with an attached functional group
Is found in the exoskeleton of arthropods
(a) The structure of the
chitin monomer. O
CH2OH OH H NH C
CH3
(b) Chitin forms the exoskeleton
of arthropods. This cicada
is molting, shedding its old
exoskeleton and emerging
in adult form.
(c) Chitin is used to make a
strong and flexible surgical
thread that decomposes after
the wound or incision heals.
Figure 5.10 A–C

16. 3 Molecules Made From Glucose – What’s the Difference?
Differences in bonding
and shape give the
molecules different
functions

17. Other Uses for Carbohydrates
Cell surface markers – carbohydrates attached to parts on the cell membrane where they act to identify the cell
ABO blood groups
are identified by
carbohydrates on
their surface