Double Helix
two strands of nucleotides wound about each other; structure of DNA
Nucleotide
A building block of DNA, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.
Purine
Adenine and Guanine
Pyrimidine
Cytosine and Thymine
Chromatin
DNA and protein
Gene
A segment of DNA on a chromosome that codes for a specific trait
DNA replication
the process of making a copy of DNA
DNA Polymerase
Unzips DNA
RNA
single-stranded nucleic acid that contains the sugar ribose
Protein Synthesis
the formation of proteins by using information contained in DNA and carried by mRNA
DNA Transcription
the process of copying a section of DNA in order to make proteins
mRNA
messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome
Introns
regions of DNA that do not code for proteins
Exons
Coding segments of eukaryotic DNA.
Codon
three-nucleotide sequence on messenger RNA that codes for a single amino acid
rRNA
ribosomal RNA; type of RNA that makes up part of the ribosome
Initiation
mRNA attaches to ribosome
tRNA
transfer RNA; type of RNA that carries amino acids to the ribosome
Anticodon
group of three bases on a tRNA molecule that are complementary to an mRNA codon
Elongation
addition of amino acids to the polypeptide chain; continues until it reaches a stop codon
Termination
the ribosome reaches a stop codon on the mRNA and protein synthesis stops.
Gene Mutation
a change in the base sequence of a gene
frameshift mutation
the mutation that causes the reading frame of mRNA codons to shift
point mutation
a mutation affecting only one or very few nucleotides in a gene sequence.