EX 3 DNA Replication

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EX 3 DNA Replication
2015-04-12 16:28:32
biol189 dna ex3
BIOL 189 EX 3
BIOL 189 Exam 3 DNA Replication
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  1. What did Hershey and Chase observe and
    conclude? (know what a bacteriophage is, and understand the experiment)
    • Hershey and Chase took bacteria
    • (e. coli) and bacteria attacking viruses (backteriopahe T2) to find if protein
    • or DNA contained genes.  (Side by side
    • radioactivity experiments)
  2. What macromolecule transfers information
    from one generation to the next?
    • DNA & RNA are long linear
    • polymers, called nucleic acids that transfer information from one generation to
    • the next
  3. What are the 3 basic components of DNA and RNA, and how are they
    • 5 Carbon sugar, phosphate
    • group, and a nitrogen base
  4. What are the 4 nitrogenous bases used in
    DNA? In RNA?
    • DNA-Adenine (A), Cytosine (C),
    • Guanine (G), Thymine (T)

    • RNA-Adenine (A), Cytosine (C),
    • Guanine (G), Uracil (U)
  5. Who discovered the molecular structure
    of DNA?
    Watson and Crick
  6. What is base complementarily (base
    pairing), and why is it important?
    • Base
    • paring=nucleotides from pairs through hydrogen bonding, to create a double
    • helix (e.g A-T, C-G).  Base pairing
    • allowed a mechanism for replication and explained structure
  7. How do the two strands of DNA line up
    (their relative directionality)?
  8. What is the directionality of a strand of DNA based on?
    • Directionality
    • of sugar-phosphate backbone carbons are numbered on the sugar (pentose
  9. How is DNA replicated? Include
    information about the replication bubble, DNA polymerase, and DNA ligase.
    • DNA
    • Polymerase: copies each strand, is direction specific.

    • Replication
    • bubble: enlarges on each end at the replication fork

    • DNA ligase:
    • fills the final gaps in the sugar phosphate group
  10. The plans in DNA are used to make
    proteins in two steps. What are they?
    • Transcription
    • RNA synthesis based on a DNA template in nucleus

    • Translation-
    • protein synthesis from RNA template in cytoplasm
  11. What is transcription, and where does it
    take place?
    • Protein
    • synthesis from RNA template, takes place in Cytoplasm
  12. Show how mRNA is transcribed from a DNA
    strand, including RNA polymerase, promoter

    sequences, and termination sequences
    • enzyme RNA
    • polymerase uses the genes from DNA template strand to make mRNA, adding
    • nucleotides in the 5’ -> 33 direction

    • 1.    
    • initiation:RNA
    • pol starts transcriptions at a promoter sequence on the DNA template strand

    • 2.    
    • elongation:
    • RNA pol elongates mRNA by adding nucleotides in on the 3’ end of the growing
    • strand

    • 3.    
    • termination:
    • when RNA pol reaches a termination sequence at the end of the gene, the mRNA
    • pol detach and float away separately
  13. What is the difference between an intron
    and an exon?
    • Introns: parts
    • of mRNA that are not used for making the protein (non-coding)

    • Exons: parts
    • of mRNA that are necessary for making proteins (coding)
  14. What is translation, and where does it occur?
    Using code in processed mRNA to make a protein-occurs in cytoplasm
  15. What is meant by redundancy of the genetic code?
    Redundancy: more than one codon fro many amino acids
  16. How does tRNA link the codon on mRNA with an amino acid?
    tRNA: 64 varieties, each one has a particular anticodon couples with a particular amino acids which it binds with
  17. Show how mRNA is translated (rRNA, tRNA, anticodon, ribosome).
    • mRNA-transcribed from DNA: contains plans to be translated tRNA-64 varieties: each one has a particular amino acid that it binds to Ribosomes: organelles with two subunits: large and small
    •      -composed of rRNA and proteins
    •      -large subunit link to tRNA
    •      -small subunit link to mRNA
  18. How does translation start and stop? Be able to translate if provided the codon chart.
    Translation starts with the ‘start’ codon AUG, and ends at any of the ‘stop’ codons
  19. What do the two subunits of the ribosome
  20. How do different types of mutations affect the organismal phenotype?
    • Base Mutations:
    • one base is replaced by another; may or may not change amino acid, may or may
    • not change protein function

    • Deletion: one
    • or more nucleotides is deleted; may change amino acid sequence from that point
    • forward unless a multiple of three

    • Insertion: one
    • or more nucleotides is added; may change amino acids sequence from that point
    • forward unless a multiple of three
  21. What are viruses, viroids, and prions?
    • Viruses: DNA
    • (ex. Chicken pox) or RNA (ex. AIDS, colds) in a protein coat which puncture the
    • cell membrane and insert genetic material to reproduce

    • Viroids: small
    • RNA molecules that infect plants- NO PROTEEIN PRODUCTION

    • Proins:
    • proteins currently thought to be misfolded; misfolding id=s contagious
  22. What is the difference between the lytic cycle and the lysogenic cycle in bacteria?
  23. Potential exam question: What two things happen to mRNA before it passes out of the nucleus, and why