Transcription & Translation 1.____ -> _____ -> ________ -> _______ 2.What is the sequence of the RNA molecule that you get from this strand of DNA? AATGCG 3.Was that the template strand or the gene strand of DNA? 1.____ -> _____ -> ________ -> _______ 2.What is the sequence of the RNA molecule that you get from this strand of DNA? AATGCG 3.Was that the template strand or the gene strand of DNA?

Homework  Quiz+  Read p , answer #1-5, due Wednesday.

Review Transcription  I have a DNA strand with these sequences: CGTTCGACTGATCGT GCAAGCTGACTAGCA RNA is made by pairing with the top strand. What is the RNA sequence that results? What kind of RNA is it? What do we call the top DNA strand? The bottom DNA strand? Where in the cell did this take place?

Translation  Translation = Assembling a tRNA sequence from an mRNA sequence.  Once an mRNA molecule is made, it leaves the nucleus and travels through the cytoplasm to a ribosome. The rest of protein synthesis happens in the ribosome.

Translation  Two parts.  First, tRNA matches up with mRNA.  tRNA = Transfer RNA,” an RNA molecule with 3 nucleotides on one side and an amino acid on the other.  (Amino acids will be the building blocks of proteins)

Translation  Each three nucleotides on the mRNA is called a codon.  The three matching nucleotides on the tRNA is called the anticodon.

Translation  If my mRNA codon is AUG, what will be the anticodon?

Translation  If my mRNA codon is AUG, what will be the tRNA anticodon? UAC  If my mRNA codon is CCG, what will be the anticodon?

Translation  If my mRNA codon is AUG, what will be the tRNA anticodon? UAC  If my mRNA codon is CCG, what will be the anticodon? GGC  If my mRNA has the codons AUG UUA CGC GGG AAA UAA, what will be the anticodon sequence?

Translation  If my mRNA codon is AUG, what will be the tRNA anticodon? UAC  If my mRNA codon is CCG, what will be the anticodon? GGC  If my mRNA has the codons AUG UUA CGC GGG AAA UAA, what will be the anticodon sequence? UAC AAU GCG CCC UUU AUU

Translation  Second step, the amino acids that are bonded to the backs of the tRNAs bond to each other.  A chain of amino acids is called a protein. Which amino acids are in the chain, and what order they’re in, determines the type of protein.

Paper models

 class.unl.edu/biochem/gp2/m_biology/animation /gene/gene_a3.html class.unl.edu/biochem/gp2/m_biology/animation /gene/gene_a3.html  Yo Yo  s s  Y Y

Protein Synthesis Overview  DNA -> RNA -> Protein -> Trait  TRANSCRIPTION: mRNA for a gene is made from one strand of DNA.  The mRNA leaves the nucleus and goes to the ribosome.  TRANSLATION: In the ribosome, tRNAs match up with their codons in the mRNA.  The backsides of the tRNAs have specific amino acids attached to them. When the tRNAs line up, the amino acids bond to each other and let go of the tRNA.  The chain of amino acids is called a protein.  The protein then performs a function which gives the organism a certain trait. (more on those functions next)

Protein Synthesis Overview  DNA -> RNA -> Protein -> Trait  So if I have a strand of DNA that’s like this:  TACGGGCTAACT  ATGCCCGATTGA  And my cell wants to produce the protein that’s coded for by this gene, in which the bottom strand is the gene strand.  What will be my mRNA sequence?  What will be my tRNA sequence?  What will be my amino acid sequence?  Which ones are identical to the gene strand sequence, and which ones are opposites?

Questions I want to address…

 Why all the hassle? Why coding and decoding, why RNA? Why not just make the protein from the DNA? Several reasons why it didn’t happen this way.  Amino acids can’t bond to DNA’s nucleic acids directly.  DNA is in extremely long, bunched up strands that are too big to pass through the pores in the nucleus.  The DNA is the cell’s master plan, and if it’s getting roughed up and zooming around through the cytoplasm, it’s accumulating damage. This will result in cell dysfunction and death, and the death of that strategy.

Sentence Coding