Ch 3: Biomolecules
Ch 3: Biomolecules
• Organic compounds
? contain
– Carbon Based
• Very Diverse Group
? 4 major
– H,O,N,C….leads to millions of types of molecules
• Carbon has 4 Valence electrons
– So can covalently bond to?
– Up to 4 elements, including itself
– When with H…
Reasons For Diversity:
1. Can Bond with other Carbons to form….
– Chains
– Branched Chains
– Rings
Ring Structure
• Aromatic Compounds
= Double bond somewhere
Ex: Benzene C6H6
Ring Structure
• Aliphatic Compounds
= Only Single Bonds
Ex: Cyclohexane
C6H12
Reasons For Diversity:
2. Varied Bonding Patterns
(Single, double, triple)
Hydrocarbons
• Alkane Single
• Alkene Double
• Alkyne Triple
Reasons For Diversity:
3. Biomolecules exist as isomers.
Same molecular formula, different structural formula
Importance in Biology?
FORM DRIVES FUNCTION!!
Reasons For Diversity:
3. Biomolecules exist as isomers. C5H12
Same molecular formula, different structurally = different properties
P/S: 4 main macromolecules, and their monomers?
• Proteins
– Amino Acids (20)
• Nucleic Acids
– Nucleotides
– DNA/RNA
• Carbohydrates
– Monosaccharides
– Sugars
• Lipids
– Fatty Acids
Reasons For Diversity:
4. Functional Groups
– Adds to the diversity of biomolecules by replacing
an H atom or a methyl group (-CH3)
– Ex: Hydrocarbon vs
alcohol
Reasons For Diversity:
4. Functional Groups
 Provides a “Fingerprint” which classifies a compound
 Helps to “Predict” how compounds will act in a
chemical reaction
 Makes molecules more reactive
 Where new bonds are formed and broken
 WHERE THE ACTION IS!
Functional Group Practice
Carbonyl C=O
Carbohydrates
• C,H,O
2:1
• Energy!
• Sugars ‘___ose’
‘simple’ =
Monosaccharides
Disaccharides (sucrose)
Polysaccharides –
Storage: Starch, glycogen,
Structure: cellulose
chitin- exoskeleton
Carbohydrate Functional Groups?
Hydroxyl (-OH) Carbonyl (-C=O)
Hexose, Pentose, Triose
Glycosidic Linkages: Dehydration Synthesis
Formation of a disaccharide
http:http://
Dehydration synthesis vs. hydrolysis
Alpha vs Beta Glucose
animation
• 1-4 linkage
Lipids
•
•
•
•
•
Long term storage of energy
Component of cell membrane structure
Protective surface coating (plant cuticle)
Insulation; nerve function (Animals)
Basis for many hormones
• Composition?
• Functional Group?
Waxes
Phospholipids
• C,H,O *No Ratio H:O
• Carboxyl -COOH
Steroids
Fats and Oils (triglycerides)
Steroids
4 interconnected
rings
• Natural…fyi
• Anabolic..fyi
Amphipathic
"amphi" = "both“
- dual nature
-polar/non-polar)
Hydrophilic
*MAJOR component
of all cell membranes
“phospholipid bilayer”
Hydrophobic
Phospholipid
vs
Triglyceride
Structure
Ester Linkages
Hydroxyl-carboxyl connection
H2O
Formation of a triglyceride
• Solid at room temp
(Animal fats)
tightly packed
• Liquid at room temp
(Plant, fish fats- aka oils)
‘kinks’ in the structure
(All single)
Proteins
• Most complex
• Primary elements?
• C, H, O, ****N
• Functional groups?
• Carboxyl –COOH
• Amine -NH2
• *Functions*
• *Forms*
• Building Blocks: Amino Acids- 20 common amino acids
Characteristics of Amino Acids
*FYI only…
Peptide Linkages
• http://www.biotopics.co.uk/as/aminocon.html
LEVELS of PROTEIN STRUCTURE
1
Peptide bonds
2
Alpha,Beta
H-bonds
3
Di-sulfide Bridges
R-group Interaction
4
4+ Tertiary Forms
Protein
Structure and
Function
Beta
• Structural framework
• Storage
• Movement: cellular
and body
• Metabolism/Catalysis
(Enzymes-Hormones)
• Transport
• Body Defense
Globular and Fibrous Proteins
Fibrous Proteins
Little or no tertiary structure.
Long parallel polypeptide chains.
Cross linkages at intervals forming long fibres or sheets.
Usually insoluble.
Many have structural roles.
E.x- keratin in hair and the outer layer of skin, collagen (a connective tissue).
-Actin/Myosin- movement
Globular Proteins
Have complex tertiary and
sometimes quaternary structures.
Folded into spherical (globular)
shapes.
Roles in metabolic reactions.
E.g.- enzymes, hemoglobin, insulin.
-antibodies/defense
Denatured Protein
The Amino
Acids
• R-groupchanges the
shape and the
function
Nucleic Acids
Phosphodiester Linkage