Transcription & Translation Sec 8.4 & 8.5
copyright cmassengale Making Proteins DNA can not make proteins DNA must be converted into RNA (ribonucleic acid) copyright cmassengale
Central Dogma 2 step process The flow of information from DNA---RNA---Proteins Transcription occurs in nucleus Translation occurs in cytoplasm
RNA Nucleic acid Made of nucleotides (monomers) Difference between RNA & DNA RNA has ribose vs. deoxyribose RNA had base the Uracil vs. Thymine Adenine will pair with Uracil (pyramidine-one ring C-U-T) Nucleotides = sugar, phosphate, base All sugars end in= OSE A-U
3 Types of RNA 1. Messenger RNA (mRNA) – carries info from DNA to Ribosomes (read RNA/make proteins) Codons(3 consecutive bases) that code for amino acids 1 codon = 1 amino acid 2. Ribosomal (rRNA) – part of the ribosom 3. Transfer (tRNA) – transfer info from mRNA to polypeptide or protein Anticodons that pair w/ codons
Transcription The process of making a copy of RNA from a DNA molecule. Make 3 types (mRNA, rRNA, tRNA) Accomplished by RNA Polymerase (acts like Helicase) Gets copied Start of gene End s Make RNA. Only transcribe one side or the other. The side that is transcribed (COPY) is called the an Not copied
copyright cmassengale RNA Polymerase will copy info in the DNA. There will be complimentary bonding (C-G, A-U) and create a transcript. The copy is called mRNA mRNA will go the cytoplasm to make a protein copyright cmassengale
copyright cmassengale mRNA now moves thru a ribosome (make protein) Every 3 letters in mRNA will code for 1 amino acid. This gives lots of variety. 4 letters in DNA & RNA (ATCG, AUCG) copyright cmassengale
copyright cmassengale Transfer (tRNA) Transfer RNA amino acids from the cytoplasm to the ribosomes to attach them the growing polypetide chain which will become proteins tRNA go to ribosome, drops on amino acids. Next go to cytoplasm. copyright cmassengale