RNA and Protein Synthesis 12-3 RNA and Protein Synthesis

Genes Genes are coded DNA instruction that control the production of proteins within the cell the first step in decoding the message of DNA is copy part of the nucleotide sequence from DNA to RNA

Structure of RNA Almost the same as DNA – they are long chains of nucleotides – sugar, phosphate and nitrogen base 3 main differences Different sugar DNA = deoxyrobose, RNA = ribose DNA is a double helix, RNA is a single strand RNA has Uracil (U) instead of Thymine (T)

Types of RNA mRNA – (messenger) RNA molecule that carries copies of instructions from a gene to the ribosome tRNA – (transfer) type of RNA molecule that transfers each amino acid to the ribosome rRNA – (ribosomal) type of RNA that helps make up ribosomes

DNA vs RNA

Protein Synthesis Two main steps Transcription Translation Takes place in the nucleus Translation Takes place at the ribosomes

Transcription Transcription is the copying of the information from DNA to mRNA RNA polymerase is an enzyme that binds to DNA and separates the DNA strands. Then it uses one strand of DNA as a template to make nucleotides of RNA The enzyme will only bind to a part of the DNA know as a promoter

Transcription

The Genetic Code Proteins get made by joining together amino acids into long chains called polypeptides The language that RNA uses to determine the amino acid sequence is called the genetic code

Every 3 nitrogen bases is called a codon or a “word” Each codon is a code for a different amino acid

Translation Translation is when the cell uses the information on the RNA to produce proteins

mRNA leaves the nucleus and attaches to a ribosome tRNA will bring amino acids to the ribosome Anticodons on the tRNA will attach to the codon of mRNA linking the amino acids together in the correct order

protein synthesis video