Welcome! March 29 th

1. Welcome! March 29th • HW tonight: finish Translation packet • Quiz WEDNESDAY, March 31st • Culminating Poster due Friday, April 2nd • 2 MORE CHAPERONES NECESSARY FOR THIS SATURDAY’s CONSERVATION TRIP. ASAP. • To do: Turn to the back of the translation packet and get ready to take some notes.

2. How much variation in DNA exists between 2 people? Hemoglobin (beta) gene sequence from person A

3. How much variation in DNA exists between 2 people? Hemoglobin (beta) gene sequence from person B

4. How much variation in DNA exists between 2 people? • About 1 in every 1,000 nucleotides is different between 2 people • (0.1% difference means 99.9% identical) • We have about 3 billion nucleotides in all, so that means there are about 3 million nucleotide differences between 2 people

5. What is the observed effect of most mutations? • No Effect (think about it: are there 3 million differences between 2 people?) • Why? • Some mutations code for the same amino acid • Most mutations are in sequences of DNA between genes. • Variation – there are a variety of traits in a population.

6. Genetic diseases • Many alleles are harmless, but some can cause specific diseases. • One disease caused by a specific mutation is sickle cell anemia

7. A Big Picture of our Understanding of Genetics • All the processes we’ve learned…take parent’s information and pass it down to offspring… • Accurately, so that… • Inaccurately, so that…

8. Culminating Genetics Project: • Easy Topics: • Lactose Tolerance/Intolerance • Sickle cell anemia (contrasting having the disease, and “normal” red blood cells) • Fruit fly pigmentation • Other: • Not suggested: Height, Weight, etc.

9. Information flow from DNA to trait messenger RNA Observed trait DNA protein Made by ribosomes outside of nucleus Stored in nucleus Transcription

10. mRNA information  protein Allow variation? Explain identical twins? Translationis the process used to convert mRNA information into proteins. - also known as “protein synthesis” Note: mRNA does not become a protein, the information on mRNA is “read” and ribosomes assemble proteins from this code messenger RNA protein

11. 4 Components used in Translation • mRNA- the message to be translated into protein. • Amino acids- the building blocks that are linked together to form the protein. • Ribosomes- the “machines” that carry out translation.

12. U C U C U G C C A C C G U C C C U A H H N C N C + S + N C N C N C - - N C N C Amino acid tRNA U A C Anti-codon A U G A G A G A C G G U G G C A G G G A U U A A Ribosome mRNA

13. tRNA(transfer RNA)- brings an amino acid to the mRNA and ribosome. • One end of a tRNA molecule has an anticodon that complements with an mRNA codon. • The other end has a specific amino acid. • A tRNA molecule with a particular anticodon always carries the same type of amino acid.

14. How does translation occur? • The ribosome binds to the mRNA molecule. • The tRNA with the anticodon that complements the first codon on the mRNA binds to the first site on the ribosome. • Another tRNA with the anticodon that complements the second codon on the mRNA binds to the second site on the ribosome.

15. U A C U C U S + N C N C A U G A G A G A C G G U G G C A G G G A U U A A Codon

16. U C U C U G U A C S + N C N C - N C A U G A G A G A C G G U G G C A G G G A U U A A Codon

17. A peptide bond forms between the first two amino acids. • The first tRNA leaves, and the ribosome moves along the mRNA to the next codon. • The next tRNA brings in the next amino acid, and a peptide bond is formed between this amino acid and the growing amino acid chain. • The process continues with the ribosome moving along the mRNA molecule and the amino acids linking together until a STOP codon is reached.

18. C U G U C U S + N C N C - N C A U G A G A G A C G G U G G C A G G G A U U A A

19. C U G C C A U C U H N C S + N C N C - N C A U G A G A G A C G G U G G C A G G G A U U A A Codon

20. C C A C U G H N C S + N C N C - N C A U G A G A G A C G G U G G C A G G G A U U A A

21. C C A C C G C U G H H N C N C S + N C N C - N C A U G A G A G A C G G U G G C A G G G A U U A A Codon

22. C C G C C A H H N C N C S + N C N C - N C A U G A G A G A C G G U G G C A G G G A U U A A

23. C C G U C C C C A H H N C N C S + + N C N C N C - N C A U G A G A G A C G G U G G C A G G G A U U A A

24. U C C C C G H H N C N C S + + N C N C N C - N C A U G A G A G A C G G U G G C A G G G A U U A A

25. U C C C U A C C G H H N C N C + + S N C N C N C - - N C N C A U G A G A G A C G G U G G C A G G G A U U A A

26. C U A U C C H H N C N C S + + N C N C N C - - N C N C A U G A G A G A C G G U G G C A G G G A U U A A

27. A U U C U A U C C H H N C N C + S + N C N C N C - - N C N C Release factor A U G A G A G A C G G U G G C A G G G A U U A A STOP Codon

28. A U U C U A H H N C N C S + + N C N C N C - - N C N C Chain of amino acids (polypeptide) A U G A G A G A C G G U G G C A G G G A U U A A

29. N S C + - - + H H H H H H H H N C N C S + S + S + + N N C N C N C N - - N C N C + + - - - - C C Protein folding

30. Allow variation? Explain identical twins? N S C + - - + H H Functional protein

31. The CODE of translation

32. CODONS mRNA nucleotides are translated in groups of 3 called codons. AUGCACUGCAGUCGAUGA

33. Each codon codes for a specific amino acid. 20 different amino acids can be used in different combinations to form a protein. For example: mRNA codonamino acid AAU asparagine CGC arginine GGG glycine

34. Amino Acid sequence determines the 3-D protein shape • Interactions between amino acids cause folding and bending of the chain Examples: • positive (+) and negative (-) parts of amino acids are attracted to each other. • hydrophobic regions are attracted to each other • Folding http://www.stolaf.edu/people/giannini/flashanimat/proteins/hydrophobic%20force.swf • Structure levels http://www.stolaf.edu/people/giannini/flashanimat/proteins/protein structure.swf

35. How is the amino acid sequence determined? • The mRNA • Each codon is a code for one amino acid DNA sequence: T A C C G A G A T T C A mRNA sequence: A U GG C UC U AA G U amino acid sequence: Met -- Ala -- Leu -- Ser

36. Allow variation? Explain identical twins?

37. Your turn • Complete the “Translation Practice” worksheet

38. Welcome! March 30th • Agenda: Gene Expression Quiz tomorrow. • You need: Translation Practice Packet, Poster Chart • To Do: Think about this: We’ve studied transcription, translation, and replication. A mistake in which of these processes would result in a genetic (“inheritable”) mutation?

39. Mutations Mutation- a change in the DNA nucleotide sequence Mutations can cause subtle or dramatic effects on observed traits in individuals

40. Observed trait DNA mRNA protein translation protein function (enzyme activity) transcription How does your DNA determine your traits? Allow variation? Explain identical twins? • Remember: • Traits are determined by the functions of proteins • Protein function is determined by protein shape • Protein shape is determined by amino acid sequence

41. Mutations can change the amino acid sequences of proteins DNA sequence: T A C C G A G A T T C A mRNA sequence: A U GG C UC U AA G U amino acid sequence: Met -- Ala -- Leu -- Ser DNA sequence: T A C C G A G A T T C A mRNA sequence: A U GG C UA U AA G U amino acid sequence: Met -- Ala -- Iso -- Ser T

42. How does this mutation change the amino acid sequence? (Original) DNA sequence: A A T G C A T A T G C A mRNA sequence: U U AC G UA U AC G U amino acid sequence: Leu -- Arg -- Ile -- Arg (Mutated) DNA sequence: A A T T C A T A T G C A mRNA sequence: U U AA G UA U AC G U amino acid sequence: Leu -- Ser -- Ile -- Arg

43. 3 types of mutations Substitution Insertion Deletion T T A C C G A G A T T C A Substituting one nucleotide for another. T A C C G A T G A T T C A Inserting one or more nucleotides T A C C G A G A T T C A Deleting one or more nucleotides

44. Frameshift mutations • One or more than one nucleotide can be added or deleted with insertion and deletion mutations. • If the number of nucleotides is not a multiple of 3, it is called a frameshift mutation. • Why do we call this a frameshift mutation? • Can substitution mutations cause frameshifts? Explain why or why not.

45. Score: __/8 4 pts total for mutation #1-4: completed translation, correctly described results & labeled the mutation (take of ½ pts where needed) 4 pts for these questions COMPLETE, LOGICAL • Which mutations had the biggest effect on the protein sequence? WHY? (#4, deletion…) • Which mutations had the smallest effect on the protein sequence? WHY? (#2, substitution…) • Connections: (any logical answer) #1: Substitution, one amino acid difference, #2: substitution, no change, #3: Deletion, frameshift (3 aminos change, no stop); #4: Deletion, frameshift,Early stop codon, protein chopped)

46. Consequences of mutations… • If a mutation in sperm or egg DNA is not fixed, the new sequence of DNA is passed on to offspring. • Over generations, more mutations accumulate. • As a result, differences occur between people’s DNA sequences!

47. Period 1: Tests Back • Ampicillin: allowed us to “select” for bacteria with pGLO, it wasn’t just for kicks. • What is NECESSARY for the last question?