Science 7 ch 4

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  1. Heredity
    Passing of physical characteristics from parent to offspring
  2. Trait
    Each different characteristics
  3. Genetics
    The scientific study of heredity
  4. Fertilization
    When a new organism begins to form when the egg and sperm join
  5. Purebred
    An organism that is the offspring of many generations that have the same trait
  6. Gene
    The factors that control a trait
  7. Alleles
    The different form of a gene
  8. Dominant Allele
    One whose traits always show up in the organism when the allele is present
  9. Recessive Allele
    A trait that is hidden when the dominant allele is present-
  10. Hybrid-
    Organism who have 2 different alleles for a trait
  11. -What were the results of Mendel's experiments or crosses?
    • When he crossed purebred plants for stem height, all were tall
    • When he crossed hybrid plants for stem height, 3/4 were tall and 1/4 were short
  12. What controls the inheritance of traits in organisms
  13. -Probability
    A number that describes how likely it is that an event will occur
  14. -Punnett square
    A chart that shows all possible combinations of alleles that can result from a genetic cross
  15. Phenotype
    The physical appearance or visible traits
  16. Genotype
    The genetic makeup of or allele combination
  17. Homozygous
    An organism that has 2 identical alleles
  18. Heterozygous
    An organism that has 2 different alleles
  19. Codominance
    The alleles are neither dominant nor recessive and both alleles are shown in the offspring.
  20. What is probability and how does it help explain the results of genetic crosses?
  21. Meiosis
    The process by which the number of chromosomes are reduced by half to form sex cells
  22. Asexual reproduction
    Has to do with the egg and sperm
  23. Haploid
    - Half the number of body cells-Diploid- The total number of body cells
  24. Diploid-
    The total number of body cells
  25. What events occur during meiosis?
  26. How is meiosis similar to mitosis?
    They both result in separation of existing cells into new ones
  27. How is meiosis different from mitosis?
  28. Meosis is responsible for reproducing gametes
    • Meisos involves not one but 2 cell divisions
    • cells that undergo meiosis reduce their number of chromosomes by half
    • Germ cells are haploid, contain one complete set of chromosomes
  29. Somatic cell
    Any cell forming the body of an organism except germ cells
  30. How is mitosis different from meiosis?
    Mitosis is responsible for reproducing somatic cellsMitosis involves one cell divisionSomatic cells are diploidCells that undergo mitosis duplicate their chromosomes
  31. Gamete
    Sex cells - sperm & egg
  32. How many pairs of chromosomes do human cells contain
  33. What Sutton observed about chromosome number
    • grasshopper sex cells have half the number of chromosomes as body cells
    • grasshopper body cells and sex cells have the same number of chromosomes
  34. Chromosome theory of inheritance?
    Genes are carried from parents to their offspring on chromosomes
  35. A number that describes how likely it is that an event will occur?
Card Set
Science 7 ch 4
Science 7th grade ch 4 genetics
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