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Transcription and Translation. Protein Structure. Made up of amino acids Polypeptide - string of amino acids bonded together (peptide bonds) Enzymes are proteins 20 amino acids are arranged in different orders to make a variety of proteins Assembled on a ribosome.
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Protein Structure • Made up of amino acids • Polypeptide- string of amino acids bonded together (peptide bonds) • Enzymes are proteins • 20 amino acids are arranged in different orders to make a variety of proteins • Assembled on a ribosome
Transcription and Translation: An Overview Transcription Translation
DNA Double stranded Deoxyribose sugar Bases: C,G A,T RNA Single stranded Ribose sugar Bases: C,G,A,U RNA vs. DNA
Transcription • mRNA from DNA • mRNA’s bases are complementary to that of DNA • C-G • A-U • NOTICE: Uracil replaces Thymine • Occurs in nucleus
Major players in transcription • RNA polymerase- • Unwind DNA sequence • mRNA is synthesized using 1 strand of DNA (template strand) • Long chain of mRNA nucleotides are createdbases complementary to the DNA template
TRANSCRIPTION ACGATACCCTGACGAGCGTTAGCTATCG GGG ACU UGC UAU **Each group of 3 bases of mRNA (see colors above) are called a codons
Transcription • After transcription, mRNA- now has the information to carry out protein synthesis
Transcription is done…what now? Now we have mRNA transcribed from the cell’s DNA. It leaves the nucleus through a nuclear pore into the cytoplasm Once in the cytoplasm, it finds a ribosome where translation can begin. The mRNA code has to be read now so a protein can be “assembled”
Translation • Second stage of protein production • mRNA is on a ribosome and “read” in groups of three bases (a codon) • tRNA brings amino acids to the ribosome
tRNA • Transfer RNA (tRNA) is bound to one amino acid on one end • tRNAanticodon complements mRNA codon. • If they do not complement, the tRNA’samino acid will not be a part of the protein!
Ribosome Reads the DNA code • Every mRNA codon of bases encode for an amino acid (see chart handout of Amino Acids) • There is a Start codon(AUG) telling the ribosome where to start translation and a STOP codon ending protein synthesis
ACGATACCCTGACGAGCGTTAGCTATCG UGC GGG ACUG UAU
After All Is Said and Done…. • The amino acid sequence forms a protein • Leads to a particular function and phenotype (trait) in an organism • Proteins can be structural (forming a part of cell materials) • Proteins can be functional (hormones, enzymes, biochemicals)
Protein Shapes Vary Amylase – an enzyme in your mouth Hemoglobin on Red blood cells
Transcription Process by which genetic information encoded in DNA is copied onto messenger RNA Occurs in the nucleus DNA mRNA Translation Process by which information encoded in mRNA is used to assemble a protein at a ribosome Occurs on a Ribosome mRNA protein as tRNA brings in its Amino Acid Transcription vs. Translation Review