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2010-02-28 16:05:15
genetics exam review usp james donaldson bruist

Review Questions for the Genetics Exam
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  1. During which phase of the cell cycle are chromosomes not condensed?
    Interphase (G1-G2).
  2. During which phase of mitosis does the nuclear envelope break down?
  3. What occurs during prophase 1 of meiosis?
    • 1.) Homologous chromosome pairs congregate
    • 2.) Crossing over occurs between homologous pairs (recombination)
  4. During which phase of meiosis do homologous pairs separate?
    Anaphase 1. Sister chromatids remain connected at this step.
  5. True or False?
    DNA synthesis occurs during interphase II.
    • False.
    • In meoisis, DNA synthesis only occurs once, during the S phase of interphase I.
  6. True or False?
    Autosomal and sex chromosomes occur in pairs.
  7. What is the basic tool by which all genes are mapped?
    A three point cross.
  8. True or False?
    Multiple recombination events may occur between distant genes. Genes are linked if an odd # of recombinations occurred.
    • False.
    • They are linked if an even # of recombinations occurred.
  9. What does it mean if two genes, with respect to one another, have a very low recombination frequency?
    They are close in proximity on the chromosome. For ex. a value of 0.010 means that 1% of the time, these two genes were recombined.
  10. If a specific characteristic in a group of offspring is determined solely by that same characteristic in the mother, what can be said of that gene?
    It is located in the circular DNA of the chloroplast/mitochondria of the mother.
  11. True or False?
    The same motif in different RNA molecules will often fill a role unique to that molecule.
    • False.
    • The same motif in different RNA molecules often serves a similar role.
  12. True or False?
    Proteins can recognize DNA and RNA sequences, but must momentarily disrupt their secondary structure.
  13. True or False?
    Induced fits involving "reading" proteins and DNA utilize nonspecific sequence deformability of the nucleic acid.
    • False.
    • Deformability relies almost solely on particular nucleic acid sequences.
    • Example: Eco RV and the GATATC
  14. In a relaxed circle, what is the relationship between LK and the number of twists?
    They are equal. There are no writhes in a relaxed circle, therefore only twists determine the LK.
  15. True or False?
    Unwinding negatively supercoiled DNA facilitates strand separation, which is essential for replication and transcription.
  16. Which base is a purine structure and has only an oxygen group facing the major groove off of carbon-6?
  17. Which base is a precursor to adenine and guanine?
  18. Which base is a methylated version of uracil?
  19. Ribonucleosides end in the suffix ______, while ribonucleotides end in the suffix ______.
    • 1.) -ide
    • 2.) -ate
  20. What prevents RNA from forming the B-type helix?
    The hydroxyl group on C-2 of ribose causes steric hindrance.
  21. Which type of helix is described as having a "donut hole?"
    Type-A. This allows the C-2 hydroxyl of RNA's ribose to avoid steric hindrance.
  22. Which type of nucleic acid-helices has its bases pushed out toward the side?
  23. What can a protein "read" to determine a nucleic acid sequence?
    • 1.) Hydrogen (electron) donors and acceptors on bases
    • 2.) Hydrophobic patches
  24. True or False?
    If a piece of double stranded DNA is unwound (but not broken), its linking number will change.
    • False.
    • Since neither strand was broken while unwinding, the linking number will remain unchanged, while writhes will compensate.
  25. What are the components (DNA and enzymatic) of a type II topoisomerase?
    • 1.) Gate segment of DNA
    • 2.) Transport segment of DNA
    • 3.) 2 ATP binding domains