Genotype to Phenotype - Introduction to Biology - Lecture Slides, Slides of Biology

Download Genotype to Phenotype - Introduction to Biology - Lecture Slides and more Slides Biology in PDF only on Docsity! From DNA to Protein: Genotype to Phenotype Docsity.com One Gene-One Polypeptide ¢ hypothesis * polypeptide Docsity.com Genetic Code • triplet code – 3 nucleotide bases – 1 triplet codes for 1 amino acid – redundancy Docsity.com Genetic Code • copied during transcription – DNA → RNA – mRNA produced • codon • reading frame Docsity.com Transcription * DNA— mRNA — copy of genetic code Docsity.com RNA Processing • only in eukaryotes • 1. mRNA end alteration – 5’ cap – poly(A) tail Docsity.com RNA Processing • 2. RNA splicing – introns – exons Docsity.com Translation • mRNA → protein • in cytoplasm – ribosomes • made of rRNA – tRNA Docsity.com tRNA • specificity of amino acid and tRNA binding occurs via specific aminoacyl-tRNA synthetase Docsity.com Ribosomes • 2 subunits made of rRNA and proteins – transcribed from DNA – assembled in nucleolus – subunits join only when mRNA binding occurs Docsity.com Ribosomes • tRNA anticodon / mRNA codon coupling – T site – A site – P site – E site Docsity.com Translation • 3. Termination – stop codon is read – release factor binds – translation complex falls apart Docsity.com Polyribosomes • one mRNA may be used to make several protein copies simultaneously Docsity.com Protein Destination • signaled by polypeptide being produced • 2 signals – 1. destination is cytoplasmic – 2. destination is the ER for further modification – signal peptide – signal recognition particle (SRP) Docsity.com Point Mutations • 1. substitutions – silent mutation – missense mutation – nonsense mutation Docsity.com Point Mutations • 2. insertions and deletions – frameshift mutations • mutagens – chemical and physical Docsity.com Chromosomal Mutations ¢ deletion * duplication ¢ inversion * translocation ® Docsity.com