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From DNA to Protein. Remember Genes On Chromosomes???. Some genes contain the instructions to make a protein. Some proteins are:. Structural. Functiona l. Gives form and structure…… Examples: Keratin (skin, nails, horns), Collagen (connective tissue), Actin and Myosin (muscles).
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Remember Genes On Chromosomes??? • Some genes contain the instructions to make a protein
Some proteins are: Structural Functional Gives form and structure…… Examples: Keratin (skin, nails, horns), Collagen (connective tissue), Actin and Myosin (muscles) Have a job to do…..Examples: Hormones (signal proteins such as insulin), enzymes, antibodies
***Proteins are polymers made up of single subunits called amino acids ***Amino acids bonded together (a peptide bond)
From Gene to Protein • DNA can’t do it alone. Needs the help of another nucleic acid molecule called RNA (Ribonucleic acid) mRNA, messenger RNA ** RNA involved: tRNA, transfer RNA
Compare DNA and RNA DNA RNA A, G, C, T A, G, C, U *Double-Stranded *Deoxyribose sugar *Single-Stranded *Ribose sugar
How are Proteins Assembled?? • 2 step process make up protein synthesis: • Transcription • Translation
Protein Synthesis is Like a Factory………. DNA, has the instructions (genetic code) to build a protein
TRANSCRIPTION The process by which DNA is ‘read’ to produce a strand of mRNA. Notice there are NO T’s in mRNA!!! RNA polymerase 5’ 3’ A G T C G T C A A T G C T A T G C A T T C C G T A C T C A G C A G T T A C G A T A C G T A A G G C A T G DNA 3’ 5’ A G U C G U C A A U G C U A U G C A U U C C G U A C mRNA 5’ 3’
Three mRNA Bases Are Called Codons ** mRNA’s codons code for one of 20 naturally occurring amino acids (See your handout) ** Eample; AUG is amino acid Methionine (Met), the codon that begins translation **A stop codon (*UAA, UAG or UGA) ends the process
mRNA binds to a ribosome that “reads” the mRNA codons mRNA codon
When tRNA (transfer RNA) has an anti-codon that compliments mRNA’s codon, it will release its amino acid Amino Acid tRNA Anti-Codon mRNA Codon
TRANSLATION Remember our strand of mRNA from before? LYS ALA THR ILE ARG ALA SER VAL SER U C A G C A G U U A C G A U A C G U A A G G C A U G C A G U C G U C A A U G C U A U G C A U U C C G U A C G
Polypeptides • Proteins are polypeptides • They fold according to its function such as enzymes and antibodies
Recall Enzymes proteins thatcontrol biochemical reactions including the synthesis ofDNA, RNA and Proteins
Let’s Synthesize! ** Look at your table of mRNA codons! ** Remember, to decipher amino acid sequence you read the mRNA codonNOT the tRNA anti-codon DNA Instruction Code TAC CCG AGC GTA TGC TTC GGA GTA ATT mRNA’s Transcription AUG GGC UCG CAU ACG AAG CCU CAU UAA tRNA’s Translation UAC CCG AGC GUA UGC UUC GGA GUA AUU Amino Acid (based on mRNA!!!) Met Gly Ser His Thr Lys Pro His Stop Start ** Notice that tRNA is EXACTLY the same as DNA but the T’s have been replaced with U’s