Presentation on theme: "DNA Transcription & Protein Translation"— Presentation transcript:
1 DNA Transcription & Protein Translation Honors BiologySOL.BIO.6f
2 Today’s ObjectivesTSW investigate and understand common mechanisms of protein synthesis.
3 DNA 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)!
4 Transcription – 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
5 Transcription – 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
6 Transcription – 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)
7 Transcription Reminders The template strand is the DNA strand being copiedThe rRNA strand is the same as the DNA strand except Us have replaced Ts
8 Protein TranslationModified genetic code is “translated” into proteinsCodon code is specific, but redundant!20 amino acids64 triplet (codon) combinations
9 tRNA in cytoplasm has a codon attached to an amino acid
10 tRNA structure 3-base code (triplet) is an “anticodon” Protein moleculeAttached amino acid that is carried from cytoplasm to ribosomes
11 Protein 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