Chapter 3The Chemical Building Blocks of Life

Trevor Morera, Daniel Guevarra, Fabian Abarca

Carbohydrates Monosaccharides – single sugar that is simple,

containing as few as three carbon atoms, but when they play a central role in energy storage, they contain six carbons

C6H12O6 is not only the chemical formula for glucose, but for both structural isomers and stereoisomers

Disaccharides (two linked monosaccharides) are effective reservoirs of glucose and serve as transport molecules and provide nutrition in plants and animals, respectively.

Carbohydrates (2) Polysaccharides which are longer

polymers made of monosaccharides joined through dehydration reactions

Starch is a storage polysaccharide, consisted of alpha glucose molecules linked in long chains, similarly to cellulose (but with beta glucose)

Chitin, found in shellfish and fungi, is a substituted version of glucose.

Lipids Lipids are hydrophobic molecules (insoluble in water). Storage fats are all one kind of lipid. Oils, waxes, and

some vitamins are also lipids Fats are complex polymers of fatty acids attached to

glycerol A fat molecule is a triglyceride, containing three fatty

acids. Saturated fats have all carbon atoms in the fatty acid

chains bonded to at least two hydrogen atoms, having all the hydrogen atoms possible

Unsaturated fats have fatty acids with double bounds between pairs of successive carbon atoms.

Lipids (2) Monounsaturated fats have one double bond. Polyunsaturated fats have more than one double

bond. Fats are excellent energy-storage molecules Most fats contain over 40 carbon atoms, ratio of

energy storing bonds in fats is more than twice that of carbohydrates

Phospholipids are complex lipids that form the core of all biological membranes, the basic structure of a phospholipid is of three subunits: glycerol, fatty acids, and a phosphate group

Nucleic Acids Nucleic acids are information molecules. Two main varieties of nucleic acids are

DNA and RNA. DNA encodes genetic information use to

assemble proteins. Nucleic acids can serve as templates to

make precise copies of themselves.

Nucleic Acids (2) Nucleic acids are long polymers of

nucleotides. A nucleic acid is basically a chain of

five-carbon sugars RNA is a transcript of a DNA strand Adenine, a nucleotide, is a key part of

ATP, other nucleotides are important in NAD+ and FAD

Proteins Proteins are molecules with diverse structures and functions,

composed of polymers of amino acids (an amino group and an acidic carboxyl group)

Protein functions are categorized into the following: enzyme catalysis, defense, transport, support, motion, regulation, and storage

There are 20 different amino acids, with a generalized structure of amino and carboxyl groups bonded to a central carbon atom, with an additional hydrogen and functional side R group

Peptide bonds link amino acids Levels of structure are: primary (amino acid sequence),

secondary (hydrogen bonding patterns), tertiary (folds and link), and quaternary (subunit arrangements)

Proteins (2) Motifs are made from secondary structure

elements that combine, fold, or crease Domains are distinct parts of a protein that

make it up Protein folding relies on chaperone proteins Improper folding results to diseases Denaturation causes proteins to become

inactive