Sections 3-4

Structure of RNA Made of nuleotides Three differences between DNA & RNA Sugar DNA = deoxyribose sugar RNA = ribose sugar RNA is single stranded RNA uses Uracil instead of Thymine to bond with Adenine

Types of RNA Three types of RNA mRNA Messenger RNA rRNA Ribosomal RNA tRNA Transfer RNA

Types of RNA Messenger RNA This is a copy of complimentary strand of DNA Eventually will code for a protein to be made

Types of RNA Ribosomal RNA RNA found in ribosomes (organelles in the cell)

Types of RNA Transfer RNA Help produce a protein from mRNA Brings amino acids (monomer of protein) to ribosome to bond them together and make a whole protein

Transcription Taking DNA and making an RNA copy Occurs in the cell’s nucleus RNA polymerase opens the DNA and adds RNA copy to the template Once this is made it is called pre-mRNA

RNA Editing Pre-mRNA is a rough draft to the final copy of mRNA Some parts of pre-mRNA are not needed to make a certain protein These unnecessary parts are called introns Introns get cut out of pre-mRNA Before leaving the nucleus, mRNA needs to get a cap and tail to finalize the RNA strand

The Genetic Code Proteins are made of amino acids There are 20 amino acids In order to make a protein from a strand of mRNA, the mRNA is read in a 3 letter sequence called codons

The Genetic Code Each three letter codon represents an amino acid DNA = AGCGTGCCA RNA = Codons = Amino acids =

The Genetic Code RNA knows when to start and stop based on the codons read There is ONE start codon: AUG There are THREE stop codons: UAA, UAG, UGA

Translation Taking mRNA and making a protein Occurs in the cytoplasm on a ribosome tRNA brings specific amino acids to ribosome If mRNA = AUG, then tRNA = UAC The tRNA has the anti-codon

Translation As new tRNA brings amino acids to the ribosome, past ones break off leaving just amino acids bonded to each other This continues until one of the three STOP codons is met Finished amino acid strand goes through protein folding

Mutations Changes in the DNA sequence that affect the cell Two types of mutations Gene mutation Chromosomal mutation

Gene Mutation Point mutation A change in one nucleotide in a DNA sequence Occur only in a single point of the DNA Can sometimes be a problem Frameshift mutation A change in the reading frame of DNA Since DNA is read in 3 letter codons, if there is an insertion, deletion, or large change in these codons the frame is changed

Chromosomal Mutation A change in the number of chrom0somes in the cell Four types Duplication Deletion Inversion Translocation