Cell reproduction

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Cell reproduction
2010-12-12 14:14:48
Biology cell reproduction mitosis meiosis binary fission Gregor Mendel DNA RNA

Biology module 3
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  1. Homozygous
    Matching pair of genes
  2. Heterozygous
    Mismatched pair of genes
  3. Alleles
    One member of a pair or series that occupy a specific position on a specific chromosome.
  4. Dihybrid cross
    One in which parentals differ in two traits
  5. Genotype
    The genetic makeup of an organisim with reference to trait
  6. Phenotype
    The set of observable charicteristics of an organisim, or of the total of it's heritable traits
  7. The principle of segregation
    states that pairs of genes segregate during gamete formation such that fusion of gametes during fertilization pairs genes in a zygote.
  8. The principle of independant assortment
    States that each pair of alleles segregate independantly during gamete formation
  9. Binary fission
    A method of asexual reproduction that involves the splitting of a parent cell into two approximately equal parts.
  10. Gene
    A sequence of nucleotides that codes for a specific protein.
  11. Gene locus
    Where a specific gene is located on a chromosome
  12. How many chromosomes and of what kind does a human have?
    23. 22 are autosomes and 1 is sexual
  13. Homologous
    Having the same number of allels or genes in the same order of arrangment
  14. Somatic
    relating to the body, the Soma
  15. Autosomes
    Any chromosomes other than a sex chromosome
  16. Centromere
    A specialized structure on the chromosome, appearing during cell division at the restricted central region where the two chromotids are held together and form an x shape
  17. Diploid
    organism or cell that has two copies of every type of chromosome. Humans are diploid. Designated as 2N (2=number of copies, N=number of types) they devid by mitosos.
  18. Haploid
    A cell that has only one copy of every type of chromosome. Designated as N. Haploid cell are gametes and devide by meiosis.
  19. Gamete
    Mature sexual reproductive cell that unites with another cell to form a new organisim
  20. Mitosis
    A process that takes in the nucleus of a dividing cell that results in the formation of a new nucleus, each having the same number of chromosomes as the parent nucleus.
  21. Meiosis
    the cellular process that results in the number of chromosomes in gamete producing cells to be reduced to one half, and that involves a reduction division in which one of each pair of homoglous chromosomes passes to each daughter cell.
  22. Cell cycle
    The sequence of events from one cell division to the next
  23. Name the steps in Interphase:
    • G1 or Gap 1 phase- where the cell increases it's supply of protein and organelles.
    • Synthsis phase- where each linear chromosome is replicated.
    • G2 or Gap 2 phase- cell increases protein and in animal cells, the centrioles appear.
  24. Name the steps of cell reproduction:
    Prophase, Metaphase, Anaphase and Telophase
  25. What happens during mitosis' prophase?
    Strands of DNA condense to form chromosomes which migrate to the poles of the cell and the nuclear envelope disappears. This cell is 2N.
  26. What happpens during mitosis' metaphase?
    Individual chromosomes line up along the equator of the cell. The spindle forms and spindle fibers become attached to the centromeres of each chromosome. This cell is 2N.
  27. What happens during mitosis' anaphase?
    The spindle fibers contract pullling the centromere and chromosome in half, and daughter chromosomes migrate to the poles of the cell. This cell is 4N.
  28. What happens during mitosis' Telophase?
    A cleavage furrow forms and the cell splits into halves. Chromosomes uncoil and the nuclear envelope reforms. Each cell daughter is 2N.
  29. Meiosis 1 is..
    Reductional division, in which a single cell gives rise to two geneticly unique haploid cells.
  30. Meiosis 2 is...
    Equational Division. The number of chromosomes in each daughter does not change.
  31. Test Cross
    the expermiental cross of an individual organisim of dominant phenotype but unknown genotype with a homozygous recessive genotype (and phenotype).
  32. What organisms undergo binary fission?
    Bacteria, alge, mushrooms and ferns.
  33. Nondisjunction
    The failure of chromosomes to seperate properly during the Anaphase which can cause disease such as Down's Syndrome.
  34. Genetic code
    The sequence of nucleatides in DNA and RNA that determine the specific amino acid sequence in the synthesis of proteins.
  35. Codon
    A series of three adjacent bases in one polynucleotide chain of a DNA or RNA molecule, which codes for a specific amino acid.
  36. Chromosome
    Any of several threadlike bodies, consisting of chromatin, that carry the genes in a linear order.
  37. Nucleotide
    Any of various compounds consisting of a nucleoside combined with a phosphate group and forming the basic constituent of DNA and RNA.
  38. How do nucleotides base pair?
    Adenine binds to thymine with 2 hydrogen bonds, and cytosine binds to guanine with 3 hydrogen bonds. In RNA thymine is replaced with uracil. A and G are purines, whereas C, T and U are pyrimidines.
  39. M phase
    The phase in which cells divide.
  40. describe the parts of Interphase.

    G1 phase:
    S phase:
    G2 phase :
    • G1 phase: The cell collects protein and increases it's organelles.
    • S phase: Linear chromosome is replicated.
    • G2 phase: Increases protein preparing to replicate.
  41. Which phase is the shortest?
    M phase
  42. What is G0 (Gap 0/Resting phase)?
    The period in which the cell is dormant.
  43. Name 2 cell types in the human body that do not divide.
    Muscle and nerve cells.
  44. Name 1 tissue type in the body that divides often.
  45. Explain the purpose of mitosis in the human body.
    Mitosis is used to repair and replace cells that wear out or die.
  46. Describe and distinguish between replicated chromosomes and homologous chromosomes.
    Replicated have a matched pair of chromosomes. Homologous have an unmatched pair.
  47. Anaphase is unique in chromosome number. Explain.
    The cell becomes an N4 until it divides and becomes two N2s.
  48. Is a cell in anaphase diploid? Explain.
    It depends. If it starts out as haploid, then yes. If it started as diploid it would be N4.
  49. What is the purpose of meiosis in the human body?
    It is for reproduction using gamete cells.
  50. Briefly describe the phases of Meiosis I.
    Prophase is where DNA condenses and forms chromosomes. But the big difference is when chromosomes form chiasmata to trade bits of DNA so that what results is an individual, different than the parent cell. Metaphase Cells line the equator, The spindle forms and attaches to chromasomes. Anaphase: The spindle pull apart the chromosomes where they migrate to the poles. Telophase: The cell splits, the nuclear envelope reappears and chromosomes unwind.
  51. Why is Meiosis I called reduction division? What is being reduced?
    The number of chromosomes, so that it will be able to unite with a gamete for sexual reproduction.
  52. What is crossing over and during which phase of Meiosis I does crossing over occur?
    The trading of genetic material. It happens in prophase.
  53. What is “Independent Assortment” of chromosomes and who is associated with this theory? During what phase of Meiosis I does it occur?
    Random combining of chromosomes when two gametes join. Gregor Mendel. The metaphase.
  54. Briefly describe what happens in each phase of Meiosis II.
    Prophase: Strands of DNA form replicated chromosomes. They migrate to the poles while the nuclear envelope disappears. Metaphase Cell lines up along the equator and spindles appear and attach to the chromosomes. Anaphase Spindle fiber pulls the chromosomes apart and they migrate to the poles of the cell. Telophase: The cell divides and the chromosomes uncoil while the nuclear envelope reforms.
  55. Centrosome
    • A cellular structure that acts as
    • an organizing center for the assembly of microtubules.
  56. Mitotic spindle
    • As the centrosomes move apart, they begin sprouting microtubules in all directions. One variety of them forms a football-shaped cage around the nuclear material, while a second variety attaches to the chromosomes themselves. Taken
    • together these are the microtubules active in cell division.
  57. Cytokinesis
    The division of the cytoplasm and the plasma membrane following the division of the nucleus resulting into two cells, each having its own nucleus and cytoplasm surrounded by a plasma membrane.