DNA, Replication, Transcription

DNA Nucleotides

Adenine, Guanine, Cytosine, Thymine

DNA Replication

The process of copying a DNA molecule

RNA Nucleotides

Adenine, Uracil, Cytosine, Guanine

mRNA

Messenger that carries genetic info from DNA to cytoplasm

Produced in nucleus by transcription

tRNA

A carrier molecule for amino acids

Molecules match an amino acid to its corresponding mRNA codon

Delivering them to the site of protein synthesis - ribosome

20 diff amino acids, also 20 types of tRNA

rRNA

Subunits join with proteins in the cytoplasm to form the subunits of ribosomes

The Genetic Code

The sequence of nucleotides in DNA provides a code for constructing a protein

Protein Construction

Conversion of a nucleotide sequence to an amino acid sequence

Transcription

Rewrites the DNA code into RNA, using the same nucleotide “language”

Initiation, Elongation, and Termination

Codons

Each “word” of a protein, consisting of three nucleotides

Initiation

RNA polymerase binds to a promoter, where the helix unwinds and transcription starts

Elongation

RNA nucleotides are added to the chain

Termination

RNA Polymerase reaches a terminator sequence and detaches from the template

Anticodon

Allows the tRNA to bind to a specific mRNA codon, complementary in sequence.

Mutation

A change in the nucleotide sequence of DNA

Mutations can be caused by

Mutagens - Radiation and chemicals

Spontaneous - Errors in DNA replication

Genetically modified organisms

Contain one or more genes introduced by animal means

Transgenic organisms

Contain at least one gene from another species

GM plants

Resistance to herbicides and pests

Improved nutritional profile

GM animals

Improved qualities

Production of proteins or therapeutics