4 Types of RNAmRNA- carries coded instructions for polypeptide (protein) synthesis from nucleus to ribosomes in the cytoplasm.rRNA- part of the subunits of ribosomes.tRNA- carries amino acids to the ribosome and matches them to the coded mRNA message.
5 TranscriptionDNA segments are used as templates to produce complementary mRNA strands.Enzyme: RNA polymeraseSample transcription sequence- pg. 367
6 How RNA Polymerase Works The enzyme binds only to promoters, or regions of DNA with specific base sequences. This enables RNA polymerase to know where to start transcription.
7 Introns and Exons Not all of the new RNA sequence is needed. The needed parts are called exons. The not needed parts are called introns.The introns are removed and the exons are then spliced back together to form the final mRNA strand.
8 The Genetic CodeThe transcribed mRNA sequence contains a code for making proteins.Proteins are made by joining amino acids (20 exist) together into long chains called polypeptides.The amino acid sequence determines the properties of a protein, such as its shape and function.
26 Beneficial Effects of Mutations Mutations that produce proteins with new or altered functions that are useful to organisms in different or changing environments.Evolution (genetic variability)Example: polyploidy