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Protein Synthesis From DNA to protein And viruses And bacteria.

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Presentation on theme: "Protein Synthesis From DNA to protein And viruses And bacteria."— Presentation transcript:

1 Protein Synthesis From DNA to protein And viruses And bacteria

2 Central Dogma You Tube Protein Synthesis (2:51)You Tube Protein Synthesis DNA Transcription and Protein Assembly (3:02) From DNA to proteins DNA Transcription and Protein Assembly FROM GENOTYPE TO PHENOTYPE (From DNA to proteins)

3 Beadle and Tatum REMEMBER US?

4 George Beadle and Edward Tatum during the late 1930s and early 1940s Using Neurospora crassa bread mold determined "one gene one enzyme hypothesis"

5 Protein Synthesis Overview get Central Dogma and Protein Synthesis Worksheets DNA Replication, Transcription, Translation Youtube (8 mins)DNA Replication, Transcription, Translation Youtube

6 Learn these Terms Transcription = DNA mRNA Translation = mRNA protein

7 Three Bases Lingo DNA Triplet ATC mRNA Codon UAG tRNA Anti-codon AUC

8 The 3 RNAs mRNA – messenger RNA – codes from DNA in the nucleus to take the genetic code to the ribosome in the cytoplasm tRNA – transfer RNA – brings a specific amino acid to the ribosome rRNA –ribosomal RNA – plus protein makes up a ribosome

9 Transcription: DNA to mRNA DNA never leaves the nucleus It codes to mRNA to take the message outside the nucleus TRANSCRIPTION YOUTUBE (1:53 )TRANSCRIPTION YOUTUBE

10 RNA polymerase (RNAP) The enzymes that makes RNA from the DNA template DNA RNA RNAP

11 Not all RNA nucleotides make the cut: Introns and Exons Primary mRNA = exons + introns INTRONS = discarded, noncoding region of mRNA EXONS = the coding regions, spliced together RNA are called also = Mature mRNA RNA Splicing Youtube Youtube (1:38)

12 SPLICING RNA Mature mRNA Or Primary RNA

13 SPLICING ANIMATION snRNPs Spliceosome Seriously detailed splicing youtubeSeriously detailed splicing youtube (1:39) McGraw-Hill How Splicesosomes Process RNA Before the mRNA leaves the nucleus, the introns are removed, and the exons are spliced together.

14 Exons leave the nucleus Mature mRNA leaves

15 Transcription Initiation Control

16 Transcription Promotors DNA sequences at start site (recognize TATA BOX) RNA polymerase and accessory proteins (transcription factors) bind to the promoter to initiate production of an mRNA transcription. TATA

17 Transcription Terminator mRNA is cut free from DNA

18 The mRNA travels out of the nucleus through nuclear pores to a ribosome in the cytoplasm The mRNA binds to a ribosome The mRNA binds to a ribosome Ribosome translates codons (use chart ) Ribosome translates codons (use chart )

19 TRANSLATION mRNA (genetic language) needs to be translated into protein language (chain of amino acids) Translation Youtube (2:06) Translation Youtube

20 TRANSLATION Coding from mRNA to making protein (at the ribosome) DNA Translation Youtube (2:06) DNA Translation Youtube

21 tRNA transports amino acids to ribosomes There is a specific amino acid for each tRNA

22 Job of tRNA Complements the codon of mRNA and picks up the appropriate amino acid ANIMATION: Animation of Translation

23 Note the A P E sites Central Dogma youtube (3:03) Central Dogma youtube A site – Amino acid is dropped off P site – Polypeptide builds E site – tRNA exits (after giving its amino acid to building polypeptide chain) APE sites of Ribosome youtube APE sites of Ribosome youtube (1:31)

24 A P E Sites at the Ribosome Translocation: movement of tRNA across the ribosome

25 Notice AUG codon means start building a new protein. UAA, UAG, UGA mean stop building the protein.

26 There are 20 Amino Acids These 20 are shared by all living organisms What does CAC code for? histidine

27 Translation Initiation mRNA attaches to the ribosome (AUG – start codon)

28 Translation Elongation tRNA brings amino acids to the ribosome

29 Translation Termination mRNA reaches one of the STOP codons Bond breaks the last tRNA and its amino acid to release the polypeptide bond

30 Cooooool Protein Synthesis 3-D CENTRAL DOGMA (2:52) CENTRAL DOGMA

31 All mRNAs start with AUG, so all DNA genes start with______?

32 Answer Methionine

33 THINK: What would happen if something caused the base sequence to change? What sorts of things could cause this? Could the base changes be repaired? Would those changes be passed on to the individuals offspring?

34 MUTATION: A change in the base sequence of a gene resulting in a different base sequence and thus different amino acid sequence. What causes mutations? MUTAGENS Thalidomide baby…

35 Mutagen =any source of mutation is a physical or chemical agent –EX: X-rays –UV light –cigarette components –Hazardous chemicals

36 Mutagens

37 Mutation Animations BBC - Education Scotland - Higher Bitesize Revision - Biology - Genetics and adaptation - Mutations: Revision 2BBC - Education Scotland - Higher Bitesize Revision - Biology - Genetics and adaptation - Mutations: Revision 2 EXPLAIN HOW EACH MUTATION IS DIFFERENT FROM THE ORIGINAL DNA SEQUENCE

38 Gene (point)mutations SUBSTITUTION – Replace one base for another. Minimal effect ADDITION – Adding a base DELETION – removing a base Addition/deletions cause a complete Frame Shift that affects the whole gene.

39 Mutation Lingo Mutation = any change in nucleotide sequence of DNA Reading frame = triplet grouping Mutagenesis = creation of mutations

40 More Mutation Lingo Nonsense mutation = change an amino acid into a STOP codon Missence mutation = change the amino acid coding Silent mutation = no change in protein product

41 Chromosome Mutations Translocation Inversion Segment of a same chromosome is turned end to end has moved one segment of a chromosome chromosome to a different chromosome

42 Translocation

43 Translocation 9 and 22


45 Cystic Fibrosis Deletion

46 Albinism is due to a mutation of the melanin pigment gene. A one base substitution results in only 1 amino acid being in error. ALBINISM

47 AAGGTTCGGAGT (DNA) type of mutation Amino acids AACGTTCGGAGT:____________________ AAGGTCTCGGAGT:____________________ AAGGTTCGAGT:_______________________

48 ANSWER- Substitution (C for the G) Insertion (the C) Deletion (the G)

49 Chromosomal mutations Affect the entire chromosome - often fatal. Mutagens can cut up DNA into pieces. When Repair mechanism reassembles them, they may be in the wrong order.

50 Oncogenes Genes that when mutated result in cancer. EXAMPLE: BRCA1 and BRCA2 Found to cause breast cancer on 81-kb region of human chromosome 17


52 Viruses Nothing more than packaged genes Simple tools for geneticists HIV EBOLA



55 Every virus has two stages a dormant, particulate, transmissible stage called the virion stage an active, intracellular stage called the infectious stage

56 Infectious Stage: Lytic Infection 1.attachment 2. Insertion of virus DNA 3. replication of virus components 4.packaging and assembly of new virions 5. exit from cell –lysis bursts

57 Bacteriophage enzyme lyses the bacteriums cell wall, releasing new bacteriophage particles that can attack other cells. Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles Bacteriophage takes over bacteriums metabolism, causing synthesis of new bacteriophage proteins and nucleic acids Bacteriophage injects DNA into bacterium Bacteriophage attaches to bacteriums cell wall Bacteriophage Bacteriophage DNA Bacteriophage protein Bacteriophage protein coat Bacteriophage DNA Bacterial chromosome Lytic Cycle The Lytic Cycle Go to Section:

58 LYTIC INFECTION Lytic Infection Animation

59 Lysogenic Infection The viral DNA becomes integrated into the bacterial DNA after infection. It is replicated along with the host DNA when the host reproduces. The viral DNA is referred to as a prophage.

60 Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles Bacteriophage enzyme lyses the bacteriums cell wall, releasing new bacteriophage particles that can attack other cells Bacteriophage DNA inserts itself into bacterial chromosome Bacteriophage DNA (prophage) may replicate with bacterium for many generations Bacteriophage DNA (prophage) can exit the bacterial chromosome Bacteriophage DNA forms a circle Bacteriophage DNA Bacterial chromosome Bacteriophage injects DNA into bacterium Prophage Lytic Cycle Lysogenic Cycle A Lysogenic Infection Go to Section:

61 DIAGRAM COMPARISON Lytic and Lysogenic Infections

62 Virus Examples RNA instead of DNA: cold, flu, HIV, polio, measles, mumps DNA viruses: herpes. Chicken pox, hepatitis Herpes infections may flare up when under stress, a cold, or sunburn

63 Ebola Virus Causes hemorrhagic fever Movie Outbreak

64 Hanta Virus Southwestern US mice carried it cardiovascular collapse, respiratory failure, and death

65 HIV Has 2 copies of RNA Is a retrovirus (RNA to DNA) Carry enzyme reverse transcriptase

66 Aids infected cells HIV = Human Immunodeficiency Virus AIDS = Acquired Immune Deficiency Syndrome

67 F Factor Fertility factor Allows one bacterium to carry genes to another by conjugation Sex pili

68 Bacterium Plasmid Circular DNA in bacteria Extra genes, not essential for bacterial survival

69 Transformation Uptake of DNA from another bacteria cell

70 Conjugation Physical union of two bacterial cells to transfer DNA

71 R Plasmid Contain genes that are resistant to many antibiotics

72 Transduction Some viruses move bacterial from one bacterial cell to another

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