a nucleic acid- that a molecule made out of     nucleotides linked together.
 

 Uracil 

one of the four bases that combine with sugar and phosphate to form a nucleotide subunit of RNA; uracil pairs with adenine. (208) 

the process of forming a nucleic acid by using another molecule as a template; particularly the process of synthesizing RNA by using one strand of DNA molecule as  a template. (208) 

Gene Expression 

the manifestation of the genetic material of an organism in the form of specific traits. (208) 

Translation 

the portion of protein synthesis that takes place at ribosomes and that uses the codons in mRNA molecules to specify the sequence of amino acids in polypeptide chains. 

RNA polymearse 

an enzyme that starts (catalyzes) the formation of RNA by using a stand of DNA molecule as a template. (209) 

codons 

In DNA, a three nucleotide sequence that encodes an amino acid or signifies a start signal or a stop signal. 

genetic code 

the rule that describes how a sequenceof nucleotides , read in groups of three consecutive nucleotides (triplets) that correspond to specific amino acids, specifies the amino acid sequence of a protein. 

Transfer RNA 

an RNA molecule that transfers amino acids to the growing end of a polypeptide chain during translation. 

Operator 

The piece of DNA that overlaps the promoter site and serves as the on-off switch is called an operator. 

Operon 

A group of genes that code for enzymes involved in the same function, their promoter site, and the operator that controls them all function together as an operon. 

lac operon 

The operon that controls the metabolism of lactose. 

repressor 

A protein that binds to an operator and physically blocks RNA polymearse from binding to a promoter site. 

A-T

C-G

 A-U