1) DNA, RNA and proteins
DNA - Read Only Memory
DNA is a polymer of the components Adenine, Guanine, Cytosine, Thymine (AGCT)
DNA is usually double-stranded
5' ACCGTGA 3'
3' TGGCACT 5'
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Base-pairing rules : A pairs with T; G pairs with C
RNA - The program resident in memory
RNA is a polymer of the components Adenine, Guanine, Cytosine and Uracil
RNA is usually single-stranded
Because of base-pairing rules, all information contained in the DNA can be represented in a single strand of RNA.
RNA encodes the sequence of protein, a "polypeptide", composed of amino acid subunits
20 amino acid subunits combine to confer unique biochemical functions to each protein
Example: Plant defensins
15 30 45 60
ATG GAG AAG AAA TCA CTA GCT TGC TTG TCC TTC CTC CTC CTC GTT CTC TTT GTT GCA CAA
M E K K S L A C L S F L L L V L F V A Q
75 90 105 120
GAA ATA GTG GTG AGT GAA GCA AAC ACA TGT GAG AAT TTG GCT GGT TCA TAT AAG GGA GTA
E I V V S E A N T C E N L A G S Y K G V
135 150 165 180
TGC TTC GGT GGA TGT GAC CGT CAC TGT AGA ACA CAA GAG GGC GCA ATT AGC GGC AGA TGC
C F G G C D R H C R T Q E G A I S G R C
195 210
AGG GAT GAC TTT CGC TGT TGG TGC ACT AAA AAC TGT TAA
R D D F R C W C T K N C *
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2) Gene Expression
