Presentation on theme: "Protein Synthesis From DNA to protein And viruses And bacteria."— Presentation transcript:
Protein Synthesis From DNA to protein And viruses And bacteria
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)
Beadle and Tatum REMEMBER US?
George Beadle and Edward Tatum during the late 1930s and early 1940s Using Neurospora crassa bread mold determined "one gene one enzyme hypothesis"
Protein Synthesis Overview get Central Dogma and Protein Synthesis Worksheets DNA Replication, Transcription, Translation Youtube (8 mins)DNA Replication, Transcription, Translation Youtube
Learn these Terms Transcription = DNA mRNA Translation = mRNA protein
Three Bases Lingo DNA Triplet ATC mRNA Codon UAG tRNA Anti-codon AUC
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
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
RNA polymerase (RNAP) The enzymes that makes RNA from the DNA template DNA RNA RNAP
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)
SPLICING RNA Mature mRNA Or Primary RNA
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.
Exons leave the nucleus Mature mRNA leaves
Transcription Initiation Control
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
Transcription Terminator mRNA is cut free from DNA
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 )
TRANSLATION mRNA (genetic language) needs to be translated into protein language (chain of amino acids) Translation Youtube (2:06) Translation Youtube
TRANSLATION Coding from mRNA to making protein (at the ribosome) DNA Translation Youtube (2:06) DNA Translation Youtube
tRNA transports amino acids to ribosomes There is a specific amino acid for each tRNA
Job of tRNA Complements the codon of mRNA and picks up the appropriate amino acid ANIMATION: Animation of Translation
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)
A P E Sites at the Ribosome Translocation: movement of tRNA across the ribosome
Notice AUG codon means start building a new protein. UAA, UAG, UGA mean stop building the protein.
There are 20 Amino Acids These 20 are shared by all living organisms What does CAC code for? histidine
Translation Initiation mRNA attaches to the ribosome (AUG – start codon)
Translation Elongation tRNA brings amino acids to the ribosome
Translation Termination mRNA reaches one of the STOP codons Bond breaks the last tRNA and its amino acid to release the polypeptide bond
Cooooool Protein Synthesis 3-D CENTRAL DOGMA (2:52) CENTRAL DOGMA
All mRNAs start with AUG, so all DNA genes start with______?
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?
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…
Mutagen =any source of mutation is a physical or chemical agent –EX: X-rays –UV light –cigarette components –Hazardous chemicals
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
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.
Mutation Lingo Mutation = any change in nucleotide sequence of DNA Reading frame = triplet grouping Mutagenesis = creation of mutations
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
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
Translocation 9 and 22
Cystic Fibrosis Deletion
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
AAGGTTCGGAGT (DNA) type of mutation Amino acids AACGTTCGGAGT:____________________ AAGGTCTCGGAGT:____________________ AAGGTTCGAGT:_______________________
ANSWER- Substitution (C for the G) Insertion (the C) Deletion (the G)
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.
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
Viruses Nothing more than packaged genes Simple tools for geneticists HIV EBOLA
Every virus has two stages a dormant, particulate, transmissible stage called the virion stage an active, intracellular stage called the infectious stage
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
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:
LYTIC INFECTION Lytic Infection Animation
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.
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:
DIAGRAM COMPARISON Lytic and Lysogenic Infections
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
Ebola Virus Causes hemorrhagic fever Movie Outbreak
Hanta Virus Southwestern US mice carried it cardiovascular collapse, respiratory failure, and death
HIV Has 2 copies of RNA Is a retrovirus (RNA to DNA) Carry enzyme reverse transcriptase
Aids infected cells HIV = Human Immunodeficiency Virus AIDS = Acquired Immune Deficiency Syndrome
F Factor Fertility factor Allows one bacterium to carry genes to another by conjugation Sex pili
Bacterium Plasmid Circular DNA in bacteria Extra genes, not essential for bacterial survival
Transformation Uptake of DNA from another bacteria cell
Conjugation Physical union of two bacterial cells to transfer DNA
R Plasmid Contain genes that are resistant to many antibiotics
Transduction Some viruses move bacterial from one bacterial cell to another