www.nicholls.edu/biol-qcf. Chapter 3. Biology Sixth Edition Raven/Johnson (c) The McGraw-Hill Companies, Inc. The Chemistry of Carbon. Organic molecules contain C and H. Because carbon only has 4 electrons in its outer shell, it can attach to four separate molecules.
Organic molecules contain C and H
Because carbon only has 4 electrons in its outer shell, it can attach to four separate molecules
Organic molecules consisting of only C and H are called hydrocarbons.
Hydrocarbon chains can have functional groups that cause the macromolecule to behave in a certain way.
Carboxyl Group: -COOH -COO¯ + H+
Energy is released when macromolecules are split.
Structure of Amino Acids
(R or Functional
Contains –O or only H
Secondary Structure - Folding due to hydrogen bond
Motifs – Characteristic secondary structure ( creates a fold or crease)
Driven into its tertiary structure by hydrophobic reactions with water, disulfide bonds, and other ionic and covalent bonds
-remember: some amino acids are nonpolar.
Domain – structurally independent functional unit
Two or more polypeptide chains associate to form a functional protein
All nucleotides have:
1.) nitrogenous base
2.) pentose sugar
3.) phosphate group
A chemical difference between DNA and RNA
Nucleotides (monomer) connected by phosphodiester bonds to form nucleic acid (polymer).
Hydrogen bonds between base pairs gives DNA its characteristic double-helix shape.
H instead of CH3
DNA vs RNA: RNA has Uracil instead of Thymine
RNA – single stranded, contains uracil, #2 C attached to OH
Nucleotide bases also play an important part in other molecules crucial to life: ATP, NAD, and FAD.
Lipids serve as long-term energy stores in cells, form membranes, and serve as hormones and insulation.
Lipids contain more energy per gram than any other
Lipids are nonpolar, thus they do not dissolve in water (hydrophobic).
All lipids are insoluble in water!!
Fatty Acids: long chains of hydrocarbons with an acidic functional group –COOH
Saturated: no double bonds between carbons, “saturated
with hydrogen”, higher melting point than unsaturated
Unsaturated: has one or more double bonds between carbons
functional group –COOH
Solids (butter) at room temperature; fatty acids can align close to each other
Liquids (corn oil) at room temperature; double bonds prevent fatty acids from aligning close to each other
Phospholipids consist of:
2 Fatty acids
Terpenes – long chain lipids; components of many biologically important pigments
All steroids characteristically have four carbon rings.
Carbohydrates contain C, H, and O and serve as quick energy and short-term energy storage.
Monomers of carbohydrates are the monosaccharides (simple sugars)
Glucose is metabolized by cellular respiration
Dehydration synthesis – consumes energy
Hydrolysis splits the disaccharides and releases energy
Your taste buds can taste the difference!
Energy storage for animals
Modified form of cellulose with a nitrogen group added to the glucose units. Structural building material in insects, many fungi, and certain other organisms.