Block One Lecture 9

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  1. Genetics
    study of what genes are, how they carry info, how info is expressed, and how genes are replicated
  2. Gene
    segment of DNA that encodes a functional product, usually a protein
  3. genome


    genome: all the enetic material in a cell

    genomics: molecular study of genomes

    geontypes: genes of an organism

    phenotype: expression of the genes
  4. Flow of genetic info can occur in three ways. Explain them.
    Within a cell: Parent Cell: DNA--Transcription--> mRNA-- translation--> Protein--> Cell metabolizes and grows

    Between generations of cells: Parent cell DNA--replication of DNA chromosome--> Cell divides--> Daughter cells

    Between cells of same generation: After replication--> Recombination
  5. Polymer of nucleotides:

    Double helix associated with __. 

    Backbone is __

    Strands held together by __.

    Strainds are __



    hydrogen bonds between AT and CG

  6. Nucleic acids
    • consists of nucleotides:
    • - pentose
    • - phosphate group
    • - nitrogen-containing (purine and pyrimidine) base
  7. DNA

    - has __. 

    - shape

    - base pairs

    double helix

    a H bonds with T

    c H bonds with G
  8. DNA is copied by __. Explain
    DNA pol

    • in 5'-->3' direction
    • initiated by RNA priemer
    • leading strand synthesized continuously
    • lagging strand synthesized discontinuously 
    • Okazaki fragments
    • RNA primers are removed and Okazaki fragments are joined by DNA pol and DNA ligase
  9. What is the process of DNA replication?
    1) enzymes unwind the parental double helix

    2) proteins stabilize the unwould parental DNA

    3) The leding strand is synthesized continously by DNA pol

    4) The lagging strand is synthesized discontinuously. NA pol synthesizes a short RNA primer, which is then extended by DNA pol

    5) DNA pol digests RNA primer and replaces it with DNA

    6) DNA ligase joins the discontinuous lfragments of the lagging strand
  10. DNA replication is __.

    Where does it begin? What forms? What two strands are there? Where does it end?

    origin of replication

    replication fork 

    parent and daughter strand

    termination of replication
  11. Transcription
    DNA is transcribed to make RNA (mRNA, tRNA, and rRNA)

    Transcription begins when RNA polymerase binds to the promoter sequence

    Transcription proceeds in the 5'-->3' direction

    Transcription stops when it reaches the terminator sequence
  12. RNA 
    - sugar

    - how many strands
    • has ribose
    • is single stranded
    • A binds with U
    • C binds with G
  13. RNA processing in Eukaryotes
    1) A gene composed of exons and introns is transcribed to RNA by RNA polymerase

    2) Processing involves ribozymes and proteins in the nucleus to remove the intron-derived RNA and splice together the exon-derived RNA into mRNA

    3) After further modification, the mature mRNA travels to the cytoplasm, where it directs protein synthesis
  14. Classes of RNA
    mRNA, rRNA, tRNA
  15. Messenger RNA
    - contains the __ for a protein
    - funcitonal units called __
    - leaves the __ and remains in the __
    - __

    - Consensus sequence __ precedes __ by __
    ---> Comlementary to the __ end of __
    • genetic coding
    • codons
    • nucleus
    • cytoplasm
    • AUG Codon: starts with Formyl-Met
    • AGGAGG
    • AUG
    • 7 bases
    • 3' end 
    • 16S rRNA
  16. mRNA characteristincs
    • Poly A tail
    • 7 Me-G Cap

    • Euk: monocistronic (one gene, one message)
    • Pro: polycistronic (one gene, several messages)
  17. tRNA

    - All tRNAs have similar sequences of __

    3' end always __with the sequence __

    Contain a number (7-15%) of unique/modified bases __ and __

    tRNAs have __secondary structure due to four __

    The cloverleaf contains __:  __, __, and __
    73 to 93 nucleotides

    • terminates 
    • CCA

    Inosine and Psuedouridine

    • cloverleaf 
    • base-paired stems

    • three non-base-paired loops
    • D, anticodon, and TpsiC loop
  18. Translation

    - mRNA is translated in __

    - Translation of mRNA begins at the __

    - Translation ends at a __.
    codons (3 nucleotides)

    start codon, AUG

    STOP codon: UAA, UAG, UGA
  19. __ are expressed at a __
    Other Genes are expressed only as needed: __ and __

    • Constitutive Genes
    • fixed rate

    • •Repressible
    • •Inducible
  20. Structure of the operon?
    the operon consists of the promoter, the operator sites, and structural genes which code for the protein. The operon is regulated by the product of the regulatory gene
  21. What happens with the repressor inactive and the operon on?
    The repressor is inactive and transcription and translation proceed leading to the synthesis of tryptophan

    When the inducer allolactose binds to the repressor binds to the repressor protein, the inactivated repressor can no longer block transcription. The structural genes are transcribed, ultimately resulting in teh production of the enzymes needed for lactose catabolism
  22. Repressor active, operon off
    When the corepressor tryptophan binds to teh repressor protein, the activated repressor binds with the operator, preventing transcription from the operon

    The repressor protein binds with the operator, preventing transcription from the operon
Card Set:
Block One Lecture 9
2014-09-27 13:13:59
Test One
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