1. Chapter 5- The Structure and Function of Macromolecules Carbohydrates
AP BIOLOGY

2. Macromolecules
Carbohydrates
Proteins
Lipids
Nucleic Acids

3. Carbohydrates

4. Polymer Vs. Monomer
Polymer: A large molecule made up of identical or similar building blocks
Ex. Polysaccaride
Starches
Monomer: the building block that is used to make polymers
Glucose

5. Carbohydrates Carbohydrates are composed of C, H, O
Most names for sugars end in –ose
CH2O (Empirical Formula)
(CH2O) C6H12O6
Contains a Carbonyl (C=O) & many Hydroxyl (OH)
Function: Energy & Storage
ex: sugars, starches, cellulose, chitin
(CH2O)x
C6H12O6
carb = carbon
hydr = hydrogen
ate = oxygen compound

6. Monosaccharides Simple 1 monomer sugars Ex’s: Glucose Frucotose
Galactose
sugar

7. Biological function of monosaccharides
ENERGY!!!!
Key parts of other molecules (e.g. nucleic acids, ATP)
Monomers for Disaccharides & Polysaccharides.
They form polymers in dehydration reactions.

8. Classifying Monosaccharides
Monosaccharides are uniquely identified based on:
The location of the carbonyl carbon in the straight chain form
The number of carbons present
The spatial arrangement of carbons

9. Sugar structure 5C & 6C sugars form rings in solution
Where do you find solutions in biology?
In cells!

10. Identifying monosaccharides
alpha-glucose
beta-glucose
The arrangement of the –OH group on the #1 carbon does not matter when naming sugars.
The location of the other groups on the 2,3,4, and 5 carbons does matter.

11. C C O C C C C Carbons are numbered energy stored in C-C bonds 5' 4' 1'6' C O 5' C C 4' 1'
energy stored in C-C bonds C C 3' 2'

12. Carbon Skeleton 6 5 3 3-7 Carbons long Classified by number of carbons
6C = hexose (glucose)
5C = pentose (ribose)
3C = triose (glyceraldehyde)
Glyceraldehyde H OH O C OH H HO
CH2OH O
Glucose H OH HO O
Ribose
CH2OH 6 5 3

13. Functional groups determine function
Aldehyde
Carbonyl at end
Ketone
Carbonyl in
middle

14. Forming Disaccharides
glucose+ glucose= Disaccharide
monomer monomer Polymer

15. Disaccharides Sucrose Lactose Maltose 2 monomers Held by
Monosaccharides
Sucrose
Glucose +
Fructose
Lactose
Galactose
Maltose
2 monomers
Held by
glycosidic bonds
Ex’s
Sucrose
Lactose
Maltose

16. Building sugars Dehydration synthesis sucrose (table sugar) glucose
monosaccharides
disaccharide
H2O
sucrose
(table sugar) |
glucose |
fructose
sucrose = table sugar

17. Building sugars glycosidic linkage glucose glucose maltose
monosaccharides
disaccharide
H2O
maltose
glycosidic linkage |
glucose |
glucose |
maltose

18. Lactose

19. Glucose and Fructose
Glucose

20. Polysaccharides Polymers of sugars costs little energy to build
Function:
energy storage
starch (plants)
glycogen (animals)
in liver & muscles
structure
cellulose (plants)
chitin (arthropods & fungi)
Polysaccharides are polymers of hundreds to thousands of monosaccharides

21. Polysaccharides Polymers of sugars joined by glycosidic linkages.
Serve two main functions
Storage- glycosidic linkages are hydrolyzed to obtain monosaccharides as energy is needed.
Structural- make up the materials that are used to protect the organism.

22. Glycosidic Bonds
Chemical linkage between the monosaccharide units of disaccharides, and polysaccharides, which is formed by the removal of a molecule of water
Condensation reaction
Bond forms between the carbon-1 on one sugar and the carbon-4 on the other.

23. Α & β Glycosidic Bonds in cellulose in starch
An α-glycosidic bond- formed when the –OH group on carbon-1 is below the plane of the glucose ring
A β-glycosidic bond is formed when it is above the plane.
Ex. Cellulose- formed of glucose molecules linked by 1-4 β-glycosidic bonds (Above plane)
Ex. Starch- composed of 1-4 α-glycosidic bonds (Below plane )
in cellulose
in starch

24. Polysaccharides- 100’s to 1000’s of monosaccharides
Storage Polysaccharides
Structural Polysaccharides
Starch
Plants
Cellulose
Glycogen
Animals
Chitin
Animals-Insects
Fungi

25. Structural Polysaccharides
Key in forming the structure of an organism.
Most common structural polysaccharide is cellulose.
Makes up cell walls in plants
Used to make paper
Chitin
Polymer of glucose
Forms via 1-4 glycosidic linkage.

26. Cellulose Most abundant organic compound on Earth
herbivores have evolved a mechanism to digest cellulose
most carnivores have not
cellulose = undigestible roughage
Cross-linking between polysaccharide chains:
= rigid & hard to digest
The digestion of cellulose governs the life strategy of herbivores.
Either you do it really well and you’re a cow or an elephant (spend a long time digesting a lot of food with a little help from some microbes & have to walk around slowly for a long time carrying a lot of food in your stomach)
Or you do it inefficiently and have to supplement your diet with simple sugars, like fruit and nectar, and you’re a gorilla.
But it tastes like hay! Who can live on this stuff?!

27. Cow Gorilla can digest cellulose well; no need to eat other sugars
can’t digest cellulose well; must add another sugar source, like fruit to diet
The digestion of cellulose governs the life strategy of herbivores.
Either you do it really well and you’re a cow or an elephant (spend a long time digesting a lot of food with a little help from some microbes & have to walk around slowly for a long time carrying a lot of food in your stomach)
Or you do it inefficiently and have to supplement your diet with simple sugars, like fruit and nectar, and you’re a gorilla.
APBioTOPICS/20Biochemistry/MoviesAP/Macromolecule-Lifewire.swf

28. Helpful bacteria How can herbivores digest cellulose so well?
BACTERIA live in their digestive systems & help digest cellulose-rich (grass) meals
Rumen-Upper part of stomach

29. Digesting starch vs. cellulose
enzyme
starch easy to digest
cellulose hard to digest
Starch = all the glycosidic linkage are on same side = molecule lies flat
Cellulose = cross linking between OH (H bonds) = rigid structure
enzyme

30. Plant Storage Polysaccharides
Starch is the main storage polysaccharide- Found in two forms.
Amylose- main storage polysaccharide found in plants.
1-4 glycosidic linkage found in glucose.
Amylopectin- also in plants.
Like starch with branching.
Branch occurs with a 1-6 glycosidic link.

31. Storage Polysaccharide in Animals
Glycogen is the main storage polysaccharide in animals.
It is even more highly branched than amylopectin.
Stored primarily in muscle and liver cells and is used when glucose stores are low.

32. Polysaccharide diversity
Molecular structure determines function
in starch
in cellulose
isomers of glucose
structure determines function…

33. Linear vs. branched polysaccharides
slow release
starch
(plant)
energy storage
Can you see the difference between starch & glycogen?
Which is easier to digest?
Glycogen = many branches = many ends
Enzyme can digest at multiple ends. Animals use glycogen for energy storage == want rapid release.
Form follows function.
APBio/TOPICS/Biochemistry/MoviesAP/05_07Polysaccharides_A.swf
glycogen
(animal)
fast release

34. Starch Unbranched Glycogen Branched Chloroplast Starch Mitochondria
Fig. 5-6
Chloroplast
Starch
Mitochondria
Glycogen granules
0.5 µm
1 µm
Amylose
Glycogen
Amylopectin
Starch
Unbranched
Glycogen
Branched

35. Difference between starch and cellulose
Starch production involves 1-4 glycosidic linkage of a-glucose monomers.
Helical shape
Cellulose production involves 1-4 glycosidic linkage of b-glucose monomers
Never branched , straight
a- Glycogen
b- Cellulose
Does this matter?

36. (a)  and  glucose ring structures
Fig. 5-7a
 Glucose
 Glucose
(a)  and  glucose ring structures

37. (b) Starch: 1–4 linkage of  glucose monomers
Fig. 5-7bc
(b) Starch: 1–4 linkage of  glucose monomers
(c) Cellulose: 1–4 linkage of  glucose monomers

38. Chitin Chitin is the structural polysaccharide in arthropods
Ex. insects, spiders, crustaceans, and fungi.
Similar to cellulose, but it has a slightly different monomer that is a derivative of glucose

39. (a) The structure of the chitin monomer. (b) (c) Chitin forms the
Fig. 5-10
(a)
The structure
of the chitin
monomer.
(b)
Chitin forms the
exoskeleton of
arthropods.
(c)
Chitin is used to make
a strong and flexible
surgical thread.

40. YES, It matters! Cellulose has a much different structure than starch.
In storage polysaccharides, the polymer hydrogen bonds mainly with itself to form helices (spirals)
Ex. Glycogen
In structural polysaccharides, the polymer hydrogen bonds with other polymer strands to form a strands that form thread like structures
Ex. Chitin & Cellulose

41. Starch vs. Cellulose
Helix
Sheet

42. IT REALLY MATTERS
Animals lack the enzymes (cellular machinery) to break down cellulose.
Only a few bacteria and fungi can break down cellulose.