chapter 11.4

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 - DNAPhenotype - Protein & environmental influences

One gene, One polypeptideHypothesis - 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 TypesRibosomal RNA (rRNA) – Makes up part of a ridosomeMessenger RNA (mRNA) – Serves as a messengerTransfer RNA (tRNA) – Read codons and Transfers amino acids

Transcription – DNA nucleotide sequences are converted to a single strand of mRNAThen, 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.

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 INTRONSThe CODING regions are called EXONSOnly 3-5% of your DNA is coded for protein synthesis