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Unformatted text preview: ules and ions.
– Thus if ÈH+: HC03- + H + · H2C03 · H20 + C02
‡ ÍH+ – But if Í H+: H20 + C02 · H 2C03 · H+ + HC03‡ ÈH +
• Thereby maintaining normal blood pH range of 7.35 – 7.45
– Acidosis: blood pH < 7.35 (Note: not acidic!)
– Alkalosis: blood pH > 7.45 Carbon — a unique element Biological Molecules
Some molecules are special in biology
• H2O - small, slightly polar molecule ﬁ
• Organic molecules are based on carbon. H
H CH H
methane lipid 1. Each carbon atom forms four bonds.
2. Carbon atoms can bond to other
carbons, thus constructing long
and/or branched chains of carbon —
the “carbon backbone ” of the
3. Carbon can form double bonds to
modify the shape or flexibility of the
Thus only carbon can form the complex
molecules needed for complex
biological functions. Functional Groups of Organic Molecules Organic Compounds (“R groups” = reactive side groups)
Ketone: C=O on C within chain
Aldehyde: C=O on terminal C of chain • Have a “carbon backbone”
— a chain of more than one
carbon. • “Organic” originally
meant “made by
Carboxylic acid – (Most still are. But some
are synthetically derived
from those that are.)
• Heyer C.f., Fig. 4.10 6 Biological Chemistry Organic Macromolecules
Forms & Features Dehydration synthesis
(condensation reaction) Large macromolecules are constructed from smaller subunits.
Forms Features Carbohydrates Sugars and starch Energy source;
Structural units Proteins Amino acids and Proteins Enzymes;
Energy source Nucleic Acids Nucleotides, RNA, DNA Genetic instructions;
Cellular energy units Lipids Fats, oils, and steroids Hydrophobic;
Energy source Dehydration ( “removing water ”) synthesis:
Forming polymers produces water as a byproduct. Hydrolysis
(digestion reaction) Organic Macromolecules
Monomers & Polymers
Large macromolecules are constructed from smaller subunits.
Subunit Macromolecule Carbohydrates Monosaccharide Polysaccharides Proteins Amino acid Polypeptide Nucleic Acids Nucleotides RNA, DNA Lipids Fatty acids
or other carbon backbone Hydrolysis (“ water breaking ”) is opposite of dehydration synthesis.
Breakdown of a polymer requires water Monosaccharides 1. Carbohydrates “single sugar” • Used for: Energy, structure • Monomer: Mono-saccharide — “one sugar”
• Polymer: Poly-saccharide — “many sugar...
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- Spring '10
- molecular biology