1. Building Blocks of Life
Macromolecules
Building Blocks of Life

2. Macromolecules
Smaller organic molecules join together to form larger molecules
macromolecules
4 major classes of macromolecules:
carbohydrates
lipids
proteins
nucleic acids

3. Polymers
Long molecules built by linking repeating building blocks in a chain
monomers
building blocks
repeated small units
covalent bonds
H2O HO H
• great variety of polymers can be built from a small set of monomers
• monomers can be connected in many combinations like the 26 letters in the alphabet can be used to create a great diversity of words
• each cell has millions of different macromolecules

4. You gotta be open to “bonding”!
How to build a polymer
You gotta be open to “bonding”!
Synthesis
joins monomers by “taking” H2O out
one monomer donates OH- (hydroxyl)
other monomer donates H+
together these form H2O
requires energy & enzymes!
H2O HO H
enzyme
Dehydration synthesis
Condensation reaction

5. How to break down a polymer
Breaking up is hard to do!
Digestion
use H2O to breakdown polymers
reverse of dehydration synthesis
cleave off one monomer at a time
H2O is split into H+ and OH–
H+ & OH– attach to ends
requires enzymes
releases energy
H2O HO H
enzyme
Most macromolecules are polymers
• build:
condensation (dehydration) reaction
• breakdown:
hydrolysis
An immense variety of polymers can be built from a small set of monomers
Hydrolysis
Digestion

6. OH H HO
CH2OH O
Carbohydrates
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

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

10. 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)

11. long term energy storage
Lipids
long term energy storage
concentrated energy

12. 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

13. dehydration synthesis
Fats
Structure:
glycerol (3C alcohol) + fatty acid
fatty acid = long HC “tail” with carboxyl (COOH) group “head”
enzyme
Look at structure… What makes them hydrophobic?
Note functional group = carboxyl
H2O
dehydration synthesis

14. Building Fats Triacylglycerol (Triglyceride)
3 fatty acids linked to glycerol
ester linkage = between OH & COOH
hydroxyl
carboxyl

15. Why do humans like fatty foods?
Fats store energy
Long HC chain
polar or non-polar?
hydrophilic or hydrophobic?
Function:
energy storage
concentrated
all H-C!
2x carbohydrates
cushion organs
insulates body
think whale blubber!

16. Saturated fats All C bonded to H No C=C double bonds
long, straight chain
most animal fats
solid at room temp.
contributes to cardiovascular disease (atherosclerosis) = plaque deposits

17. Unsaturated fats C=C double bonds in the fatty acids plant & fish fats
vegetable oils
liquid at room temperature
the kinks made by double bonded C prevent the molecules from packing tightly together
mono-unsaturated?
poly-unsaturated?

18. It’s just like a penguin…
Structure:
glycerol + 2 fatty acids + PO4
PO4 = negatively charged
It’s just like a penguin…
A head at one end
& a tail at the other!

19. Phospholipids Hydrophobic or hydrophilic? fatty acid tails =
PO4 head =
split “personality”
hydrophobic
hydrophillic
“attracted to water”
Come here, No, go away!
interaction with H2O is complex & very important!
“repelled by water”

20. Phospholipids in water
Hydrophilic heads “attracted” to H2O
Hydrophobic tails “hide” from H2O
can self-assemble into “bubbles”
bubble = “micelle”
can also form a phospholipid bilayer
early evolutionary stage of cell?
water
bilayer
water

21. 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

22. Cholesterol Important cell component animal cell membranes
helps keep cell membranes fluid & flexible
Important cell component
animal cell membranes
precursor of all other steroids
including vertebrate sex hormones
high levels in blood may contribute to cardiovascular disease

23. From Cholesterol  Sex Hormones
What a big difference a few atoms can make!
Same C skeleton, different functional groups

24. Multipurpose molecules
Proteins
Multipurpose molecules

25. 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)

26. Proteins Structure monomer = amino acids polymer = polypeptide
H2O
Structure
monomer = amino acids
20 different amino acids
polymer = polypeptide
A.a.s are joined by peptide bonds
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

27. 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
Oh, I get it!
amino = NH2
acid = COOH

28. 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
peptide bond

29. 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

30. Nucleic Acids
Information storage

31. Nucleic Acids Function: genetic material stores information
genes
blueprint for building proteins
DNA  RNA  proteins
transfers information
blueprint for new cells
blueprint for next generation
DNA
proteins

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

33. Nucleotides 3 parts nitrogen base (C-N ring) pentose sugar (5C)
ribose in RNA
deoxyribose in DNA
phosphate (PO4) group
Nitrogen base I’m the A,T,C,G or U part!
Are nucleic acids charged molecules?
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.

34. Dangling bases? Why is this important?
Nucleic polymer
Backbone
sugar to PO4 bond
phosphodiester bond
new base added to sugar of previous base
polymer grows in one direction
N bases hang off the sugar-phosphate backbone
Dangling bases? Why is this important?

35. Another interesting note…
ATP Adenosine triphosphate
modified nucleotide
adenine (AMP) + Pi + Pi + +