Polymerization is…
– the forming of large organic compounds (polymers) by the joining of smaller repeating units called monomers
M
MM
How does polymerization occur?
By Dehydration Synthesis: the removal of a water molecule to form a new bond.
HOH
H2O
HO H
HHO
Short Polymer Monomer
Dehydration removes a water molecule forming a new bond
1 2 3
1 2 3 4
How are polymers broken?
HOH
H2O
HO
H
H
HO
Short Polymer Monomer
Hydrolysis adds a water molecule to break a bond
1 2 3
1 2 3
4
• by hydrolysis - literally, “Water Splitting”
• Add water to break bonds
Carbohydrates• Formula (CH2O)n • 2:1 ratio of H:O• Carbonyl Groups• Ring form in (aq) solution• Important Energy Source• Cellular Structures• Monomer:
– Monosaccharides
• Polymers: – Disaccharides– Polysaccharides
Monosaccharides
Monosaccharides (simple sugars) – Contain 3-7 Carbons each
• Examples: Glucose, Galactose, FructoseGlucose
DisaccharidesDisaccharides (two sugars) – joined by
dehydration synthesis
• Examples: Sucrose, Maltose, Lactose– Maltose = Glucose + Glucose– Lactose = Glucose + Galactose
Sucrose
Glucose Fructose
Polysaccharides
Polysaccharides (many sugars, usually thousands)
• Examples: Starch, Glycogen, CelluloseStarch CelluloseChloroplast Starch
Glycogen
Liver Cell
Plant Cells
Cellulose
Starch and Cellulose Structures(Plant Polysaccharides)
ά – linkages (cis- formation) are easily hydrolyzed, while β - linkages (trans-formation)are not
Glycogen and Chitin (Animals Polysaccharide)
• Glycogen = glucose polymer – Stored in
liver/muscle
• Chitin = structural polymer in exoskeletons
Lipids
• Elements: C, H, O with H:O ratio > 2:1• Hydrophobic• Lipids function in:
– Energy (E) storage, – forming cell membranes, – and as chemical messengers
(ex. hormones)• Monomers: glycerol, fatty acids, sometimes
phosphate groups• Polymers:
– Fats (triglycerides)– Phospholipids– Steroids
TriglyceridesFats (Triglycerides)
– Glycerol + 3 Fatty Acids– Saturated = No Double Bonds (solid)– Unsaturated = Double Bonds (liquid)
OH
OH
OH
OH
OH
OH
Ester Bonds
PhospholipidsPhospholipids
– Glycerol with Phosphate Head + 2 Fatty Acid Chains
– Amphiphilic (“Both” “lover”)• Hydrophilic head• Hydrophobic tail
– Forms 2 layers in water– Makes up cell membranes
Phosphate
Glycerol
Fatty Acids
Steroids
OH
O
Testosterone
HO
O
Estrogen
AKA Sterols– Lipids whose Carbon Skeleton consists of 4
fused rings– Includes:
• Hormones• Cholesterol• Cortisol
– Makes up cell membranes
HOOH
O
O
OH
Proteins (Polypeptides)
• Polymers of AA– 20 AA, all varied in their “R” groups– 9 essential AA can not be made by the body
• 50% of dry weight of organisms
• Varied fcns: enzymatic, structural, hormonal, transport, storage, mvmt, defense, etc.
• Protein function unique with 3-D shape
Proteins• Protein monomers are called amino acids
– Peptide Bond: Bond between 2 Amino Acids:
HH22OO
Side Chains
Backbone
R Group =
Amino end Carboxyl end
Protein Structure
• Primary
• Secondary
• Tertiary
• Quarternary
Figure 5.24 Review: the four levels of protein structure
Polypeptides fold and twist to form a specific shape to create a functional protein
Secondary Structure
• AA H-bonded at backbone
• (no interaction btwn side chains)
• α – Helix• β - Pleated Sheats
Tertiary Structure
• More Complex Folding
• Interactions btwn side chains– H bonds– Ionic Bonding (+/-)– Hydrophobic
Interactions– Disulfide Bridges
Figure 5.22 Examples of interactions contributing to the tertiary structure of a protein
Quarternary Structure
• 2 or more polypeptide chains assemble
• Ex. Hemoglobin (4 polypeptide chains)
Figure 5.23 The quaternary structure of proteins
Functional Proteins
Hi sweeties, Do you remember
me?
In addition to what you know. I am a substrate.
I am an enzyme. I am going to try to convert you.
I am now a product.
I am a glucose now.
I am a product, too.
I am a fructose now.
I am completely unchanged, and ready for some more sucrose!
I am the active site. The substrate binds
to me.
The twisting and folding into tertiary or quarternary structures creates active sites with a specific shape that fits specific substrates that are responsible for catalyzing reactions
Factors That Affect Protein Formation
• pH• Salinity• Temperature (ex.
Boiled egg)• Denaturization =
unraveling of protein loss of shape and function
• Renaturization can occur, but not always
Figure 5.25 Denaturation and renaturation of a protein
Nucleic Acids
• Nucleic Acids– Informational Polymers: Code for all of the
proteins in an organism– Monomers: Nucleotides
• Phosphate Group• Pentose 5-C Sugar
– Ribose or deoxyribose
• Nitrogenous base– Purines (A, G)– Pyrimidines (T, C, U)
Nucleic Acids• Polymers
– DNA – RNA (tRNA, mRNA,
rRNA)
• DNA directs RNA synthesis
• RNA directs protein synthesis