Protein Synthesis (Transcription & Translation) Discuss with you neighbor; -Proteins -Ribosomes -How DNA is involved 5/9/2019

Recall for DNA: A-T, C-G If you know the order of bases on one strand, you can predict the sequence on the other. Example: ACTACCGGTACCA ________________________ In replication, each strand of DNA serves as a pattern to make a new DNA molecule. 5/9/2019

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An Overview of Protein Synthesis Protein synthesis=making a protein Proteins are made up of long chains of amino acids There are 20 different amino acids Proteins=traits Peptide Bonds hold amino acids together The sequence of DNA bases is a code for protein synthesis DNA determines which proteins are made RNA is necessary to put proteins together. 5/9/2019

DNA vs. RNA DNA RNA Sugar Ribose Number of Strands 2 1 Bases ATCG AUCG Deoxyribose Ribose Number of Strands 2 1 Bases ATCG AUCG 5/9/2019

Types of RNA Messenger RNA (mRNA)-RNA that transports information from DNA in the nucleus to the cell’s cytoplasm Transfer RNA (tRNA)-RNA that transports amino acids to the ribosomes to be assembled into proteins. Ribosomal RNA (rRNA)-makes up ribosomes—clamps onto mRNA and uses its information to assemble amino acids in the correct order 5/9/2019

Protein Synthesis is a 2 Step Process 1. Transcription—making an RNA version of a DNA strand 2.Translation—making a protein 5/9/2019

Transcription Part 1 of Protein Synthesis DNARNA (mRNA TRANSCRIBES DNA) The genetic code for a protein is TRANSCRIBED from DNA into RNA mRNA carries this code to the ribosomes where protein synthesis takes place. mRNA specifies the order in which amino acids are joined to form a protein. 5/9/2019

The Process of Transcription 1. Enzymes unzip DNA (enzyme=helicase) 2.Free floating RNA nucleotides bond to exposed DNA nucleotides on one of the strands Example: DNA strand: AGC TAA CCG RNA strand: UCG AUU GGC *3mRNA bases=codon 5/9/2019

Transcription (Continued) 3. Sugars and Phosphates form covalent bonds to form a new backbone. 4. A terminator is reached to indicate the end of the protein—transcription stops, mRNA detaches from DNA 5. mRNA travels to ribosome where translation occurs. 5/9/2019

Transcription… T R A N S C I P O 5/9/2019

Part 2 of Protein Synthesis; Translation * the conversion of mRNA into amino acids (protein) at a ribosome * amino acids are carried to the ribosome by tRNA The anticodon on tRNA matches with the 3 letter codon on the mRNA strand. Ex. mRNA - ACU (codon) matches with tRNA – UGA (anticodon) 5/9/2019

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YOUtubeVideo DNA 5/9/2019