Presentation on theme: "DNA Transcription & Protein Translation"— Presentation transcript:
1DNA Transcription & Protein Translation Honors BiologySOL.BIO.6f
2Today’s ObjectivesTSW investigate and understand common mechanisms of protein synthesis.
3DNA Transcription DNA must be copied to messenger RNA (mRNA) mRNA goes from nucleus to the ribosomes in cytoplasmmRNA complements known as codonsOnly 3 nucleotide “letters” longRemember RNA has uracil (U) instead of thymine (T)!
4Transcription – Step I Template DNA Strands A C G T A T C G C G T A T G C A T A G C G C A TTemplate DNA Strands
5Transcription – Step II A C G T A T C G C G T AU G C A U A G C G C A UTemplate DNA is Matched Up with Complementary mRNA Sequences
6Transcription – Step III A C G U A U C G C G U AU G C A U A G C G C A UmRNA leaves nucleus and goes to ribosomesA new complementary RNA strand is made (rRNA)
7Transcription Reminders The template strand is the DNA strand being copiedThe rRNA strand is the same as the DNA strand except Us have replaced Ts
8Protein TranslationModified genetic code is “translated” into proteinsCodon code is specific, but redundant!20 amino acids64 triplet (codon) combinations
9tRNA in cytoplasm has a codon attached to an amino acid
10tRNA structure 3-base code (triplet) is an “anticodon” Protein moleculeAttached amino acid that is carried from cytoplasm to ribosomes
11Protein Synthesis Start: Ribosome binds to mRNA at start codon (AUG) Elongation:tRNA complexes bind to mRNA codon by forming complementary base pairs with the tRNA anticodonThe ribosome moves from codon to codon along the mRNA.Amino acids are added one by oneRelease: release factor binds to the stop codon