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Chapter 5 The Structure and Function of Macromolecules
Some believe…
¢ Primitive Earth provided inorganic precursors from which organic molecules could have been synthesized due to the free energy and absence of a significant quantity of oxygen
¢ In turn, these molecules served as building blocks for the formation of more complex molecules
Fig. 4-2
Water vapor
H2 NH3
“Atmosphere”
Electrode
Condenser
Cold water
Cooled water containing organic molecules
Sample for chemical analysis
H2O “sea”
EXPERIMENT
CH4
• 1953 – Miller set up a closed system to simulate conditions though to have existed on early Earth
• These complex reaction sets could have occurred in solution (organic soup) or as reactions on solid reactive surfaces
Introductory Terms
¢ Macromolecule ¢ Monomer
l Example: • Lego block • letters
¢ Polymer l Example:
• Lego castle • words
Reaction Types
¢ Hydrolysis** ¢ Dehydration** ¢ Endergonic ¢ Exergonic ¢ Redox (OIL RIG)
Macromolecular Reactions J
¢ Dehydration Synthesis:
¢ Hydrolysis:
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4 Macromolecules (polymers) fall into 4 major groups
1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids
Carbohydrates
¢ Structure: l C:H:O in a 1:2:1 Ratio l Example: C6H12O6
¢ Functions: l Short-term energy storage
• Pasta dinner before the big race, game, etc.
l Structural Support
Carbohydrate Types
¢ Monosaccharide ¢ Disaccharide ¢ Polysaccharide ¢ Pentose ¢ Polysaccharide Structural molecules
Carbohydrates
¢ Monosaccharides: l “one sugar” l C:H:O Ratio =
1:2:1 l Simple ring
sugars l Examples:
• Glucose and fructose
Carbohydrates
¢ Disaccharides: l “double sugar” l 2 monosaccharides
joined together by dehydration synthesis
l Example: • Sucrose • Lactose
Carbohydrates
¢ Polysaccharides l Polymers – lots of
monosaccharides are linked together
l Starch and glycogen are examples
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Pentose - carbs ¢ 5 carbon sugars
Structural Carbohydrates
¢ Structural Polysaccharides l Cellulose l Chitin
Lipids - Fats ¢ Structure:
l C, H, O l Hydrophobic (insoluble)
¢ Functions: l Insulation and long-term energy storage
¢ Types: l Fats & Oils l Waxes l Phospholipids l Steroids
Fats ¢ Structure:
dehydration synthesis
Lipids
¢ Examples l Glycerol l Triglycerol
Lipids – saturated vs. unsaturated
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Lipids - phospholipids Phospholipids in water
Lipids - steroids
2005-2006
From Cholesterol → Sex Hormones ¢ What a big difference a little atom can make!
Proteins
¢ Most of a cell is made up of proteins ¢ Instrumental in almost everything
organisms do ¢ Structure:
l All proteins are created from unique combinations
l C,H,O,N l Amino acids
• Peptide bonds
Proteins - function ¢ Major Functions:
l Structure (keratin in hair & nails) l Motion (actin & myosin in muscles) l Transport (hemoglobin transports oxygen) l Signaling (hormones can signal cells to
respond) l Defense (antibodies) l Enzymes (speed up chemical reactions by
lowering activation energy)
l **(Energy (last resort for humans) 4 Cal/g)**
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¢ A protein is one or more polypeptides precisely twisted, folded and coiled into a molecule of unique shape (3-D)
¢ 4 shapes l Primary l Secondary l Tertiary l Quaternary
Protein structure Protein - structure
Proteins ¢ Denaturation:
l When pH, salt concentration, extreme heat, and/or other environmental factors are altered, the protein may unravel and lose its shape
l Biologically inactive l Structure + function l (A change in
structure alters function)
protein denatured video
Nucleic Acids
Informational polymers made of : l Nucleotides:
1. Sugar 2. Phosphate 3. Nitrogen base (A, T, G, C, U*)
l CHNOPS
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Nucleic Acids Nucleic Acids - differences
¢ RNA is single stranded; DNA is double stranded
¢ RNA has uracil instead of thymine ¢ RNA has ribose sugar, & DNA has
deoxyribose sugar. Functions: DNA serves as the genetic code for production
of proteins. RNA- DNA’s helper