1. Macromolecules
Chapter 3

2. Macromolecules are polymers, built from monomers
A polymer is a long molecule consisting of many similar building blocks
These small building-block molecules are called monomers
Three of the four classes of life’s organic molecules are polymers:
Carbohydrates
Proteins
Nucleic acids
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

3. The Synthesis and Breakdown of Polymers
A condensation reaction or more specifically a dehydration reaction occurs when two monomers bond together through the loss of a water molecule
Enzymes are macromolecules that speed up the dehydration process
Polymers are disassembled to monomers by hydrolysis, a reaction that is essentially the reverse of the dehydration reaction
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

4. Dehydration removes a water molecule, forming a new bond H2O
Fig. 5-2a HO 1 2 3 H HO H
Short polymer
Unlinked monomer
Dehydration removes a water
molecule, forming a new bond
H2O
Figure 5.2 The synthesis and breakdown of polymers HO 1 2 3 4 H
Longer polymer
(a)
Dehydration reaction in the synthesis of a polymer

5. HO 1 2 3 4 H H2O HO 1 2 3 H HO H (b) Hydrolysis adds a water
Fig. 5-2b HO 1 2 3 4 H
Hydrolysis adds a water
molecule, breaking a bond
H2O
Figure 5.2 The synthesis and breakdown of polymers HO 1 2 3 H HO H
(b)
Hydrolysis of a polymer

6. Carbohydrates OH H HO
CH2OH O
Energy Molecules

7. Carbohydrates are composed of C, H, O
(CH2O)x C6H12O6
Function:
energy u energy storage
raw materials u structural materials
Monomer: sugars
ex: sugars, starches, cellulose
(CH2O)x
C6H12O6
carb = carbon
hydr = hydrogen
ate = oxygen compound
sugar

8. Sugars 6 5 3 Most names for sugars end in -ose
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

9. energy stored in C-C bonds
Numbered carbons C 6' C O 5' C C 4' 1'
energy stored in C-C bonds C C 3' 2'

10. Simple & complex sugars
Monosaccharides
simple 1 monomer sugars
glucose
Disaccharides
2 monomers
sucrose
Polysaccharides
large polymers
starch OH H HO
CH2OH O
Glucose

11. Polysaccharides Polymers of sugars Function:
costs little energy to build
easily reversible = release energy
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

12. Long term energy storage…
Lipids
Long term energy storage…

13. Lipids Lipids are composed of C, H, O “Family groups”
long hydrocarbon chains (H-C)
“Family groups”
fats
phospholipids
steroids
Do not form polymers
big molecules made of smaller subunits
not a continuing chain
Made of same elements as carbohydrates but very different structure/ proportions & therefore very different biological properties

14. Fats store energy Long HC chain Function: polar or non-polar?
hydrophilic or hydrophobic?
Function:
energy storage
concentrated
all H-C!
2x carbohydrates
cushion organs
insulates body
What happens when you add oil to water
Why is there a lot of energy stored in fats?
• big molecule
• lots of bonds of stored energy
So why are we attracted to eating fat?
Think about our ancestors on the Serengeti Plain & during the Ice Age. Was eating fat an advantage?

15. Phospholipids Hydrophobic or hydrophilic? fatty acid tails =
PO4 head =
split “personality”
hydrophobic
hydrophillic
“attracted to water”
“repelled by water”

16. Steroids Structure: 4 fused C rings + ??
different steroids created by attaching different functional groups to rings
different structure creates different function
examples: cholesterol, sex hormones
cholesterol

17. Multipurpose molecules
Proteins
Multipurpose molecules
clockwise:
Rubisco — most important protein on the planet?
Hemoglobin — a red blooded protein :-)
Collagen — strings you together
Growth Hormones — working hard in you right now!

18. Proteins Most structurally & functionally diverse group
Function: involved in almost everything
enzymes (pepsin, DNA polymerase)
structure (keratin, collagen)
carriers & transport (hemoglobin, aquaporin)
cell communication
signals (insulin & other hormones)
receptors
defense (antibodies)
movement (actin & myosin)
storage (bean seed proteins)
Storage: beans (seed proteins)
Movement: muscle fibers
Cell surface proteins: labels that ID cell as self vs. foreign
Antibodies: recognize the labels
ENZYMES!!!!

19. Proteins Structure monomer = amino acids polymer = polypeptide
H2O
Structure
monomer = amino acids
20 different amino acids
polymer = polypeptide
protein can be one or more polypeptide chains folded & bonded together
large & complex molecules
complex 3-D shape
Rubisco = 16 polypeptide chains
Hemoglobin = 4 polypeptide chains (2 alpha, 2 beta)
hemoglobin
Rubisco
growth hormones

20. Amino acids H O | H || —C— C—OH —N— R Structure central carbon
amino group
carboxyl group (acid)
R group (side chain)
variable group
different for each amino acid
confers unique chemical properties to each amino acid
like 20 different letters of an alphabet
can make many words (proteins)
—N— H R

21. dehydration synthesis
Building proteins
Peptide bonds
covalent bond between NH2 (amine) of one amino acid & COOH (carboxyl) of another
C–N bond
H2O
dehydration synthesis
free COOH group on one end is ready to form another peptide bond so they “grow” in one direction from N-terminal to C-terminal
peptide bond

22. Building proteins Polypeptide chains have direction
N-terminus = NH2 end
C-terminus = COOH end
repeated sequence (N-C-C) is the polypeptide backbone
can only grow in one direction

23. Primary (1°) structure Order of amino acids in chain
amino acid sequence determined by gene (DNA)
slight change in amino acid sequence can affect protein’s structure & its function
even just one amino acid change can make all the difference!
Sickle cell anemia: 1 DNA letter changes 1 amino acid = serious disease
Hemoglobin mutation: bends red blood cells out of shape & they clog your veins.
lysozyme: enzyme in tears & mucus that kills bacteria

24. Secondary (2°) structure
“Local folding”
folding along short sections of polypeptide
interactions between adjacent amino acids
H bonds
weak bonds between R groups
forms sections of 3-D structure
-helix
-pleated sheet
It’s a helix or B sheet within a single region. Can have both in one protein but a specific region is one or another

25. Tertiary (3°) structure
“Whole molecule folding”
interactions between distant amino acids
hydrophobic interactions
cytoplasm is water-based
nonpolar amino acids cluster away from water
H bonds & ionic bonds
disulfide bridges
covalent bonds between sulfurs in sulfhydryls (S–H)
anchors 3-D shape
How the whole thing holds together

26. Quaternary (4°) structure
More than one polypeptide chain bonded together
only then does polypeptide become functional protein
hydrophobic interactions
Structure equals function wonderfully illustrated by proteins
Collagen is just like rope -- enables your skin to be strong and flexible.
hemoglobin
collagen = skin & tendons

27. Protein denaturation Unfolding a protein
conditions that disrupt H bonds, ionic bonds, disulfide bridges
temperature pH
salinity
alter 2° & 3° structure
alter 3-D shape
destroys functionality
some proteins can return to their functional shape after denaturation, many cannot

28. Nucleic Acids
Information storage

29. Nucleic Acids Examples: Structure: RNA (ribonucleic acid)
single helix
DNA (deoxyribonucleic acid)
double helix
Structure:
monomers = nucleotides
DNA
RNA

30. Nucleotides 3 parts nitrogen base (C-N ring) pentose sugar (5C)
ribose in RNA
deoxyribose in DNA
phosphate (PO4) group
DNA & RNA are negatively charged:
Don’t cross membranes.
Contain DNA within nucleus
Need help transporting mRNA across nuclear envelope.
Also use this property in gel electrophoresis.

31. Types of nucleotides 2 types of nucleotides different nitrogen bases
purines
double ring N base
adenine (A)
guanine (G)
pyrimidines
single ring N base
cytosine (C)
thymine (T)
uracil (U)

32. 5. 1) Which term includes all others in the list
5.1) Which term includes all others in the list? A) monosaccharide B) polysaccharide C) carbohydrate D) disaccharide

33. 5. 1) Which term includes all others in the list
5.1) Which term includes all others in the list? A) monosaccharide B) polysaccharide C) carbohydrate D) disaccharide

34. 5. 2) Which of the following is not a protein
5.2) Which of the following is not a protein? A) cholesterol B) an enzyme C) insulin D) hemoglobin

35. 5. 2) Which of the following is not a protein
5.2) Which of the following is not a protein? A) cholesterol B) an enzyme C) insulin D) hemoglobin

36. 5.3) Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes? A) The purines would be separated from the deoxyribose sugars. B) All bases would be separated from the deoxyribose sugars. C) The phosphodiester bonds between deoxyribose sugars would be broken. D) The two strands of the double helix would separate. E) The pyrimidines would be separated from the deoxyribose sugars.

37. 5.3) Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes? A) The purines would be separated from the deoxyribose sugars. B) All bases would be separated from the deoxyribose sugars. C) The phosphodiester bonds between deoxyribose sugars would be broken. D) The two strands of the double helix would separate. E) The pyrimidines would be separated from the deoxyribose sugars.

38. 5.4) Which of the following statements concerning unsaturated fats is true? A) They contain more hydrogen than saturated fats having the same number of carbon atoms. B) They are more common in animals than in plants. C) They have fewer fatty acid molecules per fat molecule. D) They have double bonds in the carbon chains of their fatty acids. E) They generally solidify at room temperature.

39. 5.4) Which of the following statements concerning unsaturated fats is true? A) They contain more hydrogen than saturated fats having the same number of carbon atoms. B) They are more common in animals than in plants. C) They have fewer fatty acid molecules per fat molecule. D) They have double bonds in the carbon chains of their fatty acids. E) They generally solidify at room temperature.

40. 5.5) The structural level of a protein least affected by a disruption in hydrogen bonding is the A) tertiary level. B) primary level. C) secondary level. D) quaternary level.

41. 5.5) The structural level of a protein least affected by a disruption in hydrogen bonding is the A) tertiary level. B) primary level. C) secondary level. D) quaternary level.

42. Practice FRQ – Macromolecules

44. Practice FRQ – Macromolecules (10 points)