Bio: Genetics

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Bio: Genetics
2011-05-10 23:01:27
gene genetics DNA

Show Answers:

  1. When doing a punnett square for 2 parents and their child's possibility of a trait, how many punnett squares do you do?
    2, one for each possibility
  2. When doing a punnett square for genes or genotypes, what is different?
    • You use X's and Y's with the capital and lower case letters.
    • Examples:
    • XBXb
    • XBY
    • *note: Y will never get a letter with it.
  3. Why do sex-linked traits typically affect more men than women?
    Males have 1 X chromosome, which is where the sex-linked trait is located, and the Y chromosome is blank.
  4. When does independent assortment occur?
    Metaphase I of meiosis
  5. During Anaphase II of meiosis, what separates?
    SISTER chromatids
  6. What causes nondisjunction?
    when a mitotic spindle breaks during cytokenesis.
  7. Phenotype
    observable or physical trait
  8. Genotype
    genetic code that explains phenotype
  9. Gene
    unduplicated segment of a chromosome that codes for a trait
  10. Allele
    alternate form of a trait or gene
  11. Homozygous
    • 2 copies of the same allele
    • Examples:
    • YY or yy
  12. Heterozygous
    • 1 copy of each allele
    • Example:
    • Yy
  13. Pleiotropy
    one gene affects many phenotypes
  14. Polygenic inheritance
    many genes affect 1 phenotype
  15. External thing that affects gene expression
  16. Chance of having a boy or girl?
    50% for both
  17. Which is physically bigger: X or Y chromosome?
  18. X chromosome has _____ base pairs
    Y chromosome has _____ base pairs
    • X= 153 million
    • Y= 50 million
  19. Colorblindness is ______ and on the ___ chromosome.
    recessive; X