Chapter 11.4

Genotype: Genetic Make-up. The nucleotide sequence in DNA. Phenotype - Expressed trait. The organisms specific traits lies in protein and their wide variety of functions. Genotype - DNA Phenotype - Protein & environmental influences

One gene, One polypeptide Hypothesis - Beadle & Tatum The function of an individual gene is to dictate the production of a specific enzyme. Genes dictate the production of a polypeptide Information flow - DNA to RNA to Protein Gene - sequence of bases Bases - “Language Letters” Many genes - “Sentence”

RNA: Ribonucleic Acid - On the molecular level - the sugar is a ribose instead of a deoxyribose  Contains nitrogenous base called Uracil (U) instead of Thymine (T)  A - T for DNA  A - U for RNA  Is a single twisted strand -not a double like DNA **Responsible for traveling outside the cell to make proteins in the ribosomes

3 RNA Types Ribosomal RNA (rRNA) – Makes up part of a ridosome Messenger RNA (mRNA) – Serves as a messenger Transfer RNA (tRNA) – Read codons and Transfers amino acids

Transcription – DNA nucleotide sequences are converted to a single strand of mRNA Then, the RNA (transcribed messages) leaves the nucleus and goes to the cytoplasm where it directs the ribosomes to make proteins **What happens is the “nucleic acid language” is now written in an “amino acid language” so the ribosomes can understand it…that is the transcription.

The CODING regions are called EXONS In Eukaryotes some DNA does not code so a message needs to be “edited” so only the coding information is sent out. NON-coding regions are called INTRONS The CODING regions are called EXONS Only 3-5% of your DNA is coded for protein synthesis