Biological Life Cycle

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  1. Biological Life Cycle
    • the passage from one adult through the reproductive stages to the adult of the next generation
    • Occurs only in sexually reproducing species
    • Includes diploid (2n) and haploid (n) phases
  2. Principal Types of Biological Life Cycles
    • Diplobiontic (gametic)
    • Haplobiontic (zygotic)
    • Alternation of Phases (haplodiplobiontic or sporic)
  3. Requirements of a Biological Life Cycle
    • Meiosis
    • Syngamy
  4. Syngamy
    fusion of gametes to form the zygote (2n)
  5. Chromosomes
    • Packages of DNA and proteins 
    • Contained in the Nucleus
    • Occurs in eukaryotic organisms
    • Consistent chromosome numbers
    • Offspring receives two sets, one from each parent
    • 23 per Set
  6. Haploid
    • "half-ploid"
    • One Set of Chromosomes
  7. Diploid
    Two sets of Chromosomes
  8. Other Sets of Chromosome Names
    • Triploid 
    • Polyploid
  9. Meiosis
    • Produces gametes (n)
    • Reduction cell division
    • Reduces the number of chromosomes
    • Diploid -> haploid
  10. Mitosis
    • Duplication cell division
    • Chromosome # stays the same
    • Diploid -> Diploid
    • Haploid -> Haploid
  11. Types of Syngamy
    • Isogamy
    • Anisogamy
    • Oogamy
  12. Isogamy
    • Gametes equal size
    • Both motile
  13. Anisogamy
    • Gametes unequal size
    • Both motile
  14. Oogamy
    • Gametes unequal size
    • Egg nonmotile
    • Sperm may be motile or nonmotile
  15. Features of Meiosis
    • When it occurs
    • In what structures it takes place
    • The products of meiosis
    • The roles of these products
  16. Characteristics of Mitosis
    Where mitosis occurs in the life cycle
  17. Diplobiontic Life Cycle (Gametic Life Cycle)
    • Typical of many animals, especially vertebrates, including mammals
    • Meiosis occurs in diploid (2n) cells in the primary sex organs (gonads) of the reproductive adults and makes gametes (eggs and sperm)
    • Only the gametes are haploid
    • Organism spends most of its life in the diploid condition
    • Zygote divides by mitosis
  18. Meiosis in Diplobiontic
    • When: adult individual
    • Structures: gonads
    • Products: sperm or eggs
    • Roles: gametes
  19. Mitosis in Diplobiontic
    Diploid phase only
  20. Haplobiontic (Zygotic) Life Cycle
    • The zygote divides by meiosis to produce haploid cells
    • Haploid cells divide by mitosis
    • Some Haploid cells act as gametes
    • The organism spends most of its life in the haploid condition
    • Typical of many protists and fungi
    • Zygote only diploid
  21. Meiosis in Haplobiontic
    • When: following syngamy
    • Structures: zygote
    • Products: vegetative cells
    • Roles: can be vegetative or gametes
  22. Mitosis in Haplobiontic
    Haploid phase only
  23. Alternation of Phases (Haplodiplobiontic/Sporic)
    • Unique to plants
    • Reproduction alternates between a multicellular diploid form and a multicellular haploid form
  24. Phases (Alternation of Phases)
    • diploid and haploid forms of the plant
    • Sporophyte
    • Gametophyte
  25. Sporophyte
    • diploid form of plant
    • "spore producing plant"
    • Cells known as sporocytes divide by meiosis to produce spores
    • Each spore grows into a multicellular haploid gametophyte
  26. Gametophyte
    • haploid form of plant
    • "gamete producing plant"
    • Cells in the haploid gametophytes differentiate to become gametes, i.e. sperm and egg
  27. Meiosis in Haplodiplobiontic (Alternation)
    • When: adult sporophyte
    • Structures: sporangia
    • Products:spores
    • Roles: divide to form multicellular gametophyte
  28. Mitosis in Haplodiplobiontic (Alternaton)
    Both haploid and diploid phases
Card Set:
Biological Life Cycle
2014-11-06 05:15:20
BIO 181 Exam III
Cyclin' thru lief
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