1. Do Now
Scientist
Discovery
Hershey and Chase
A. Analyzed DNA by X-Ray crystallography
Watson and Crick
B. Proved that the nuclear material in a bacteriophage, not the protein coat infects a bacterium.
Rosalind Franklin
C. Suggested the DNA structure of the double helix
Griffith
D. Discovered transformation in bacteria
Match above.
A court reporter types out a transcript of the court proceedings. What does the underlined word mean?

2. RNA

3. Objectives SWBAT describe the 3 types of DNA.
SWBAT describe the central dogma of biology
SWBAT compare transcription in the prokaryote and eukaryote.

4. Children of the Night Xeroderma pigmentosum
mQA

5. I. RNA Structure RNA= ribonucleic acid
RNA is the 2nd type of nucleic acid– it is also made of millions of nucleotides

6. DNA RNA Double stranded Sugar: deoxyribose Adenine bonds to thymine
Only one type of DNA per organism
Single stranded
Sugar: ribose
No thymine! Adenine bonds instead to uracil
3 types of RNA

7. Types of RNA There are 3 types of RNA:
mRNA: messenger RNA, carries the information for protein synthesis
rRNA: ribosomal RNA, makes the ribosomes in the cells functional. If there is no rRNA on the ribosomes, they won’t function
tRNA: transfer RNA, takes amino acids from the cytoplasm to the ribosomes to make them into proteins

8. mRNA

9. rRNA

10. tRNA

11. Practice 1
Which type of RNA is responsible for helping bring amino acids to make proteins?
Which type of RNA makes up ribosomal subunits ?
What type of RNA is this and what is it’s function? 

12. Function of RNA
What does RNA actually do in the cell? RNA helps make the proteins coded for by DNA
To make proteins, the cell takes DNA, copies the sequence into an RNA copy and then makes proteins. This idea is called the Central Dogma

13. Central Dogma

14. RNA Transcription How is the RNA Strand Actually Made? Transcription
Transcription= when you make an RNA copy of a sequence of DNA
What enzyme is in charge of RNA transcription? RNA polymerase

15. What nucleotide does RNA have instead of thymine?
Uracil

16. RNA Transcription RNA transcription is very similar to DNA replication
BUT! Instead of putting a Thymine (t) next to each Adenine (A), RNA Polymerase puts a Uracil (U) there

17. Practice
What will the RNA strand be?
DNA Strand:
TAAGCGCTCG

18. Transcription: Initiation
Step 1: Initiation
RNA polymerase binds to a certain site on the DNA called the promoter and DNA strands unwind.
RNA polymerase starts to make RNA.
The stretch of DNA that is transcribed is called the transcription unit.

19. Transcription: Elongation
Step 2: Elongation
RNA polymerase adds nucleotides to the 3’end of the RNA molecule.
*RNA polymerase can only add 5’  3’
The DNA double helix reforms as RNA polymerase moves away.

20. Transcription: Termination
Step 3: Termination
A sequence eventually tells the RNA polymerase to stop.
The RNA polymerase falls off, and the mRNA transcript is created!
60 nt/s in EUK

21. Animation
mat/molgenetics/transcription.swf

22. Practice
A DNA template strand has the following sequence: TACGGGATT. What is the mRNA sequence transcribed from the DNA?
Arrange the flow of genetic information in the cell in order: 1. mRNA, 2. DNA, 3. protein.
Come up with a way to remember the three steps of the transcription! (picture, saying, drawing) Be prepared to share out!

23. Where is this happening in the cell?
What’s the main difference between prokaryotic and eukaryotic cells?

24. Differences

25. Prokaryotic Transcription & Translation

26. Eukaryotic mRNA modification
After transcription, pre-mRNA in the nucleus is modified at BOTH ends.
5’ cap: adds a modified Guanine molecule, then nucleotides
Poly-A Tail: Adenine nucleotides are added at the 3’ end

27. RNA Splicing 8000 nucleotides  1200 nucleotides (average)
Introns: intervening sequences that are cut out of the pre-mRNA
Exons: regions left in pre-mRNA to be made into proteins (eventually expressed)

28. Practice Where does transcription happen in prokaryotic cells?
Where does transcription happen in eukaryotic cells?
Which are the introns and exons in the following picture?

29. MIT OCW
rtM

30. Replicate:
TTTT

31. Replicate:
ATCG

32. Transcribe:
CGC

33. Transcribe:
TAG

34. Replicate:
GCGCGCG

35. Transcribe:
GGTTAGC

36. Replicate:
TAATAAG

37. Transcribe:
AAA

38. Transcribe:
GGG

39. Transcribe:
ATGCG

40. Replicate:
CCGGTTAA

41. Replicate:
TATCGC

42. Replicate:
ACGGTA

43. Replicate:
TTACGA

44. Replicate:
TATAGGC

45. Transcribe:
GCGCGCG

46. Transcribe:
CCGTAT

47. Transcribe:
GTCGAG

48. Transcribe:
TACCAG

49. RNA Translation Objectives:
SWBAT understand and describe the process of translation in the cells

50. Central Dogma
DNA  RNA  Proteins
Transcription
Translation

51. Translation
Translation: the process of decoding mRNA into a polypeptide chain
In translation, the information in a nucleic acid is converted into amino acids
Which type of RNA is translated? mRNA

52. Translation
Where does RNA Transcription happen? The same place as DNA replication  the nucleus
Where does translation occur? On the ribosomes

53. Genetic Code CGA UGA AAA
Genetic Code: the information that the RNA carries that specifies the amino acids that will be made
Every 3 nucleotides code for an amino acid. These 3 letter codes are called a codon.
1 codon = 3 nucleotides = 1 amino acid
AAA

54. Practice
Using the genetic code in your guided notes, what is the amino acid for the codon AGU?
SERINE

55. Practice 1 Complete practice 1 on your worksheets
Total time: 5 minutes

56. To transfer amino acids from the cytoplasm to the ribosome
tRNA
Who Can Remember?! What is the function of tRNA?
To transfer amino acids from the cytoplasm to the ribosome

57. tRNA tRNA has a cloverleaf pattern
At one end of the tRNA is the anticodon, it bonds with the codon in the mRNA (it is a complementary sequence)

58. tRNA
At the other end of the tRNA is the amino acid that the mRNA codes for

59. tRNA AAA phenylalanine
Example: the mRNA codon is UUU (remember that RNA does not have thymine but has uracil instead)
What will be the anticodon for this mRNA?
What amino acid will be carried by this tRNA molecule?
AAA
phenylalanine

60. Steps of Translation
Step 1: mRNA leaves the nucleus and attaches to the ribosome
Step 2: tRNA brings specific amino acids to the RNA (according to the mRNA codons)
Step 3: tRNA bonds to the mRNA and its amino acid attaches to the growing polypeptide chain

61. More Terms
The mRNA sequence is very long. How does the cell know at which codon to start making the protein and which codon to stop?
“Start” codon: This codon tells the protein chain to start building. The start codon is AUG or the amino acid methionine. Methionine is therefore the first amino acid in all proteins
“STOP” codon: there are 3 stop codons: UAA, UGA and UAG

62. Transcription Game