MACROMOLECULES

1. CHAPTER 5
The Structure and Function of
Macromolecules
“You are what you eat!”

3. - Anorexia and
bulimia are major
eating disorders
suffered in the
world

4. Iron deficiency
Normal RBC’s

5. Goiter: Iodine Deficiency
Thyroid Enlargement

6. Rickets: vitamin D deficiency

7. Bodybuilding

8. What does it mean to be a
MACROmolecule?
 You must be a Large molecule
 You have a complex structure
Macromolecule
“little” molecule

9. I. Most macromolecules are polymers,
built from monomers
 What is a polymer?
• Poly = many; mer = part.
• A long molecule made of monomers bonded
together
 What is a monomer?
• A monomer is a sub-unit of a polymer.

10.  Three of the classes of life’s organic molecules are
polymers
• Carbohydrates, Proteins, Nucleic acids

11. A. Making and Breaking Polymers
 How do monomers bind to form polymers?
• condensation reactions called dehydration
synthesis (removal of water)

12. How can polymers break down when
monomers are needed?
 Hydrolysis reaction
• Hydro = water; lysis = break
• Water is added and the lysis of the polymer
occurs.

13. Hydrolysis

14. II. Classes of Organic Molecules:
• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids

15. A. CARBOHYDRATES

16.  What are Carbohydrates?
• Sugars and their polymers
• Carbo = carbon, hydrate = water; carbohydrates
have the molecular formula (CH2O)n
 Functions of Carbohydrates in living things:
• Major fuel/energy source
• Can be used as raw materials for other
Macromolecules
• Complex sugars = building material in plants
 What is the Carbohydrate Monomer?
• Monosaccharide (“mono” = one; “saccharide” =
sugar)

17. 1. Structure of Monosaccharides
 Contain only C, H, O
 Hydroxyl group is attached to each carbon
 One carbon contains a carbonyl group

18. • Classified according to the size of their carbon chains and
location of Carbonyl group

19.  In aqueous solutions many monosaccharides form
rings:

20. 2. Structure of Disaccharides
 Consist of two monosaccharides
 Are joined by a glycosidic linkage
 What reaction forms the glycosidic linkage?
• Dehydration synthesis

22. 3. Polysaccharides
 Structure: Polymers of a few hundred or a few
thousand monosaccharides.
 Functions: energy storage molecules or for
structural support:

24.  Starch is a plant storage form of energy, easily
hydrolyzed to glucose units

25.  Cellulose is a fiber-like structural material made of
glucose monomers used in plant cell walls

26. Why is Cellulose so strong?
 Glucose monomers are flipped to expose equal Hydroxyl
groups on either side of the chain
 When Cellulose chains are lined up next to each other, they
Hydrogen Bond making a strong material that’s difficult to
break!

28.  Glycogen is the animal short-term storage form
of energy
 Glucose monomers

29.  Chitin is a polysaccharide used as a structural
material in arthropod exoskeleton and fungal cell
walls.

30. B. LIPIDS
 What are Lipids?
• Fats, phospholipids, steroids, waxes, pigments
• Hydrophobic (“hydro”=water; “phobic” = fearing)
• Consist mostly of hydrocarbons
• Do NOT consist of polymers

31.  Functions of Lipids in living things:
• Energy storage
• membrane structure
• Protecting against desiccation (drying
out).
• Insulating against cold.
• Absorbing shocks.
• Regulating cell activities by hormone
actions.

32. 1. Structure of Fats (Triglycerides)
 Consist of a single glycerol and usually three fatty
acids
 Glycerol – an alcohol with three carbons
 Fatty Acid - Long Hydrocarbon chains with a
Carboxyl group at one end.

34. Saturated and Unsaturated Fats
 Unsaturated fats :
• one or more double bonds
between carbons in the fatty
Oleic acid
acids allows for “kinks” in the
tails
• liquid at room temp cis double bond
(b) Unsaturated fat and fatty acid
causes bending
• most plant fats
 Saturated fats:
• No double bonds in fatty acid
tails
• solid at room temp
• most animal fats
Stearic acid
(a) Saturated fat and fatty acid

36. Saturated fatty
acid

37. Saturated fatty
acid
Unsaturated
fatty acid
Why are Unsaturated Fats better for
you than Saturated Fats?

38. 3. Phospholipids
 Structure: Glycerol + 2 fatty acids + phosphate
group.
 Function: Main structural component of
membranes, where they arrange in bilayers.

39. Phospholipids in Water

40. 4. Waxes
 Function:
• Lipids that serve as coatings for plant
parts and as animal coverings.

41. 5. Steroids
 Structure: Four carbon rings with no fatty acid tails
 Functions:
• Component of animal cell membranes (Ex:
Cholesterol)
• Modified to form sex hormones

42. PROTEINS

43. C. Proteins
 What are Proteins?
• Chains of amino acid monomers connected by
peptide bonds
• Have a 3 dimensional globular shape

44. Examples of Protein Functions
 Immune System
• Binding of antibodies (proteins) to foreign substances
 Transport
• Membrane transport proteins that move substances across
cell membranes
• Hemoglobin carries oxygen, iron, and other substances
through the body.
 Muscle Contraction
• actin and myosin fibers that interact in muscle tissue.
 Signaling
• Hormones such as insulin regulate sugar levels in blood.

46. Amino Acids
 Monomers of polypeptides
• Molecules with carboxyl and amino groups
• Differ in their properties due to differing side
chains, called R groups

47. 20 different
amino
acids exist
The sequence of
amino acids and the
interactions of the
different amino acids
determine a proteins
shape

48.  Peptide bonds connect amino acids to form
polypeptide chains
 One or more polypeptide chains make up a
protein

49. Proteins are very complex! Their specific
structure determines their function.
HEMOGLOBIN: Transport of
ACTIN: Filament involved in
gases and iron in blood
muscle contraction

50. Four Levels of Protein Structure
 Primary structure HN +
3
Gly ProThr Gly
Glu
Thr
Gly Amino acid
Amino end
Cys LysSeu
subunits
• Is the unique sequence of
LeuPro
Met
Val
Lys
Val
amino acids in a
Leu
Asp
AlaVal Arg Gly
Ser
Pro
Ala
polypeptide
Glu Lle
Asp
Thr
Lys
Ser
Lys Trp Tyr
Leu Ala
Gly
lle
Ser
ProPheHis
Glu His
Ala
Glu
Val
Ala Thr PheVal
Asn
lle
Thr
Asp Tyr Ala
Arg
Ser Arg Ala
GlyPro
Leu
Leu
Ser
Pro
SerTyr
Tyr
Thr Ser
Thr
Ala
Val o
Val
ThrAsnProLys
Glu c
o–
Figure 5.20 Carboxyl end

51.  Secondary structure
• Is the folding or coiling of the polypeptide into a
repeating configuration resulting from hydrogen
bonding of amino with carboxyl groups
• Includes the α helix and the β pleated sheet
β pleated sheet
O H O H O O H
H H H H H
R
Amino acid C C N R C C N R C C N C C N
N N C N
subunits C N R CC R
C C R C R C C
H O H O H O H O
H H H
R R R R
O O C O C O
C C
H H H H
C N C N H C N C N H C N C N H C N C N
H H H H
C H O C H O C H O C H O C
R R R
R R
C H C H
N H O C N H O C
N
O C
H
O C
N H
α helix
C
H C R H R H C R H C R
N H O C N H
O C
O C N H O C N
C C H
R R H
H
Figure 5.20

52.  Tertiary structure
• Is the overall three-dimensional shape of a
polypeptide
• Results from interactions between amino
acids and R groups
Hydrophobic
interactions and
CH CH van der Waals
CH22
H3C CH3 interactions
O
Hydrogen H H3C CH3 Polypeptide
bond O CH backbone
HO C
CH2 CH2 S S CH2
Disulfide bridge
O
CH2 NH3+ -O C CH2
Ionic bond

53.  Quaternary structure
• Is the overall protein structure that results from the
aggregation of two or more polypeptide subunits

54.  Chaperonins
• Are protein molecules that assist in the proper
folding of other proteins
Correctly
folded
Polypeptide
protein
Cap
Hollow
cylinder
Chaperonin Steps of Chaperonin 2 The cap attaches, causing the The cap comes
3
(fully assembled) Action: cylinder to change shape in off, and the properly
1 An unfolded poly- such a way that it creates a folded protein is
peptide enters the hydrophilic environment for the released.
Figure 5.23 cylinder from one end. folding of the polypeptide.

56. Sickle Cell Disease: A simple change in Primary Structure

57. Enzymes
 Are a type of protein that acts as a catalyst, speeding
up chemical reactions up to 10 billion times faster
than they would spontaneously occur.

58. Environmental Factors That Determine
Protein Conformation
 Change in environment may lead to denaturation
of protein (pH, temperature, salinity, etc.)
 Denatured protein is biologically inactive
 Can renature if primary structure is not lost

59. NUCLEIC
ACIDS

60. D. Nucleic Acids : The stuff of
Genes
 Nucleic acids store and transmit hereditary information
 Genes
• Are the units of inheritance
• Program the amino acid sequence of polypeptides
• Are made of nucleic acids

61. Two Kinds of Nucleic Acids
 DNA (Deoxyribonucleic acid)
• double stranded
• can self replicate
• makes up genes which code for proteins
is passed from one generation to another
 RNA (Ribonucleic acid)
• single stranded
• functions in actual synthesis of proteins
coded for by DNA
• is made from the DNA template molecule

63. 1. Nucleotide Monomer Structure
 Both DNA and RNA are composed of nucleotide
monomers.
 Nucleotide = 5 carbon sugar, phosphate, and
nitrogenous base
Deoxyribose in DNA Ribose in RNA

65. 2. Building the Polymer
 Phosphate group of one nucleotide forms strong
covalent bond with the #3 carbon of the sugar of
the other nucleotide.

66. DNA:
• Double helix
• 2 polynucleotide chains wound
into the double helix
• Base pairing between chains
with H bonds
•A-T
•C-G

67. Summary of the Organic
Molecules: