1. Review Question 1
How many molecules of water are needed to completely hydrolyze a polymer that is 4 monomers long? 3

2. Review Question 2
After you eat a slice of apple, which reactions must occur for the amino acid monomers in the protein of the apple to be converted into proteins in your body?
Amino acids are incorporated into proteins in your body by dehydration reactions

3. CARBOHYDRATES

4. Carbohydrates Serve as fuel and building material
Include both sugars and their polymers (starch, cellulose, etc.)

5. Sugars Monosaccharides Are the simplest sugars
Contain a single chain of carbon atoms with hydroxyl groups
They also contain carbonyl (aldehyde or keytone) groups
Can be combined into polymers

6. Examples of monosaccharides
Triose sugars (C3H6O3)
Pentose sugars (C5H10O5)
Hexose sugars (C6H12O6)
H C OH
H C OH
HO C H
H C OH
C O
HO C H H C O
Aldoses
Glyceraldehyde
Ribose
Glucose
Galactose
Dihydroxyacetone
Ribulose
Ketoses
Fructose
Figure 5.3

7. Monosaccharides May be linear Can form rings OH 4C 3 2
H C OH
HO C H
H C O C 1 2 3 4 5 6 OH 4C
6CH2OH 5C
H OH
2 C 1C
3 C 2C
1 C
CH2OH HO
(a) Linear and ring forms. Chemical equilibrium between the linear and ring
structures greatly favors the formation of rings. To form the glucose ring,
carbon 1 bonds to the oxygen attached to carbon 5.
Figure 5.4
The first (1) carbon is the carbon that has the carbonyl group attached to it.

8. α glucose vs. β glucose
50% of the time when glucose forms rings, alpha glucose is formed as opposed to beta glucose

9. Oligosaccharides – contain two or three monosaccarides attached by covalent bonds called glycosidic linkages
Disaccharides
Consist of two monosaccharides
Are joined by a single glycosidic linkage

10. Figure 5.5 CH2OH O H H OH HO OH H2O
Dehydration reaction in the synthesis of maltose. The bonding of two glucose units forms maltose. The glycosidic link joins the number 1 carbon of one glucose to the number 4 carbon of the second glucose. Joining the glucose monomers in a different way would result in a different disaccharide.
Dehydration reaction in the synthesis of sucrose. Sucrose is a disaccharide formed from glucose and fructose. Notice that fructose, though a hexose like glucose, forms a five-sided ring.
(a)
(b) H HO
H OH OH O
CH2OH
H2O 1 2 4
1– 4 glycosidic linkage
1–2 glycosidic linkage
Glucose
Fructose
Maltose
Sucrose
Figure 5.5

11. Polysaccharides Polysaccharides
Are polymers of sugars with several hundred to several thousand monosaccharide subunits held together by glycosidic linkages
Serve many roles in organisms

12. Storage Polysaccharides
Chloroplast
Starch
Amylose
Amylopectin
1 m
(a) Starch: a plant polysaccharide
Figure 5.6
Starch
Is a polymer consisting entirely of glucose monomers
Is the major storage form of glucose in plants

13. Two types of Starch Amylose Amylopectin
Straight chain polymer of α (alpha) glucose
Has 1-4 glycosidic linkages
Amylopectin
Branched chains of α glucose and β glucose
Has 1-4 glycosidic linkages in the main chains and 1-6 glycosidic linkages at the branch points

15. Glucose Storage in Animals
Glycogen
Consists of glucose monomers
Similar to Amylopectin (has 1-4 and 1-6 glycosidic linkages), but there are more branches in glycogen
Stored in muscle and liver

16. (b) Glycogen: an animal polysaccharide
Mitochondria
Giycogen granules
0.5 m
(b) Glycogen: an animal polysaccharide
Glycogen
Figure 5.6

17. Structural Polysaccharides
Cellulose
Is a polymer of glucose
Has different glycosidic linkages than starch
The main structural polysaccharide in plants and plant cell walls

18. Cellulose is a straight chain polymer of β glucose with 1-4 glycosidic linkages
(c) Cellulose: 1– 4 linkage of  glucose monomers H O
CH2OH OH HO 4 C 1
(a)  and  glucose ring structures
(b) Starch: 1– 4 linkage of  glucose monomers
 glucose
 glucose
Figure 5.7 A–C

19. Unlike amylose and amylopectin (starches), cellulose molecules are neither coiled nor branched
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

20. Cellulose is difficult to digest
However, it does contribute to “roughage” in the diet  fibre
Cows have microbes in their stomachs to facilitate this process
Figure 5.9

21. Chitin, another important structural polysaccharide
Is found in the exoskeleton of arthropods
Can be used as surgical thread
(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