Protein Synthesis Chapter 10
RNA • ribonucleic acid • contains the sugar ribose, uses uracil instead of thymine • is single stranded • usually much shorter in length than DNA (about the length of one gene)
RNA & Transcription During transcription, RNA polymerase binds to DNA and separates the DNA strands. RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled.
RNA vs. DNA RNA DNA So why the big diff? Single-stranded molecule in most of its biological roles and has a much shorter chain of nucleotides. Containsribose Complementary nucleotide to adenine is uracil Double-stranded helix Contains deoxyribose Complementary nucleotide to adenine isthymine
How Genes Work • Genes are coded DNA instructions that control the production of proteins with in the cell. • The first thing that needs to happen is for DNA to be copied into RNA. (transcription) • Now the RNA contains the coded information for making proteins.
The many faces of RNA Vocab!! Yes!! Messenger RNA (mRNA): carries copies of instructions for assemble of amino acids into proteins from DNA to the rest of the cell Ribosomal RNA (rRNA): makes up the major part of the ribosome Transfer RNA (tRNA): transfers amino acids to ribosomes during protein synthesis
The Genetic Code mRNA has a “4” letter alphabet: A, U, C, G “words” (codes) are only 3 letters long each 3 letter “word” is called a codon
The Genetic Code • Start codon: AUG • mRNA: indicates where translation should begin • Stop codons: UAA, UAG, UGA • Signal for translation to end
The Genetic Code UCGCACGGU UCG-CAC-GGU Serine-Histidine-Glycine
Translation Definitely a definition. DNA replication RNA transcription mRNA translation polypeptide Decoding of a mRNA message into a polypeptide chain (amino acids) Takes place on the ribosomes.
Translation • mRNA has the codon • tRNA has the anticodon