hydrogen bonds: Weak, highly directional bonds. These are very important in the bonding of the complementary bases together. A to T and G to C (and in RNA-DNA matches U-A).
double helix: Two antiparallel strands of DNA with a three dimensional structure of a tight helix.
complementary base pairing: The specific and exclusive binding of G to C and A to T (except in RNA where U substitutes for T)
transcription:
codon: The 3 nucleotide segment on mRNA that recognizes a specific tRNA molecule. Each 3 base segement codes for a particular amino acid or the "stop" code.
translation: The process of going from the nucleotide code (as mRNA) to the amino acid code (as polypeptide). This process takes place at the ribosomes.
RNA polymerase: The enzyme that uses DNA as a template and makes a complementary strand of messenger RNA as the product.
DNA polymerase: The enzyme that uses DNA as the template and makes two, semi-conservative copies of DNA (each half new, half old). This enzyme is responsible for replication of DNA information and is not involved in gene expression directly.
promoters: regions on the DNA that bind efficiently to the RNA polymerase
repressor protein:
operon: a region of DNA that contains a promoter, a regulatory region and one or more genes that code for proteins
mRNA: messenger RNA, produced in transcription and used as a template in translation
rRNA: ribosomal RNA. The ribosomes are made up of RNA and proteins.
tRNA: transfer RNA, links to amino acid on one end and has an anticodon that matches the codon sequence on mRNA on the other end. Used in translation.
Adenosine>: one of the bases, pairs with T
Guanine:one of the bases, pairs with C
Cytosine:one of the bases, pairs with G
Thymine:one of the bases, only found in DNA, pairs with A
>Uracil:one of the bases, only found in mRNA, pairs with T
ribosome: a complex of RNA and protein that is the site of translation
anticodon:the three base portion of the tRNA molecule that matches the codon on mRNA