BIO 100 EXAM 2

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  1. Genotype
    the particular genetic makeup of an individual
  2. Phenotype
    The visable measureable features of an individual
  3. Chromosome
    a single, large DNA molecule wrapped around proteins (histones); located in the nuclei of most eukaryotic cells
  4. Sister Chromatids
    • one of the two identical DNA molecules that make up a duplicated chromosome following DNA replication
    • connected at a region of the chromosome known as the centromere
  5. Homologous chromosomes
    • Same gene different alleles
    • The two copies of each chromosome in a diploid cell. one chromosome in the pair is inherited from the mother, the other is inherited from the father
  6. How are the X and Y chromosomes different from homologous chromosomes?
    Genes located on the X and Y chromosome in males do not have a second copy
  7. What are alleles?
    Alternative versions of the same gene that have different nucleotide sequences
  8. Diploid
    • having two copies of every chromosome
    • sex cells or gametes
  9. Haploid
    • Having only one copy of every chromosome
    • somatic cells (non-reproductive cells)
  10. Autosomes
    paired chromosomes present in both males and females; all chromosomes except the X and Y chromosomes
  11. Sex Chromosomes
    • Paired chromosomes that differ between male and female
    • XX= Female
    • XY= Male
  12. In humans, does the male or female determine the sex of the child?
  13. Heterozygous
    Having two different alleles of a given gene
  14. Homozygous
    Having two identical alleles of the same gene
  15. Dominant
    An allele that can mask the presence of a recessive allele
  16. Recessive
    an allele that reveals itself itself in the phenotype only if the organism has two copies of that allele
  17. What is the genotype of a person who is heterozygous dominant?
  18. ***What are the two major sources by which genetic variation is introduced into offspring?
    • -mutation
    • -chromosomes passed down
  19. Crossing over
    • Homologousmaternal and paternal chromosomes pair up and swap genetic information. Maternal chromosomes actually contain segments from paternal chromosomes and vice versa
    • Meiosis I
  20. Independent assortment
    • Alleles of different genes are distributed independently of one another, not as a package. A unique combination of maternal and paternal chromosomes is distributed into each sperm and each egg.
    • Meiosis II
  21. Describe the 3D structure of DNA.
    • two strands of linked nucleotides are bound together and twisted around each other to form a spiral-shapped double helix
    • the sugars and phosphates = backbone
    • bases = rungs
  22. Where is DNA found in a cell?
    inside the nucleus in the form of chromosomes
  23. What are the componets of chromosomes?
    DNA and protein (histones)
  24. What holds the sugar and phosphate groups together?
    Ester Bonds
  25. What holds the bases together?
    Hydrogen bonds
  26. What are the three componets of a nucleotide?
    a sugar, a phosphate and a base
  27. Describe the assembly of the nucleotide into the 3D structure of DNA.
    • the outside is phosphate groups and sugars alternating
    • the middle is A,T,C,G held together by hydrogen bonds attached to a sugar
  28. Describe the process of DNA replication.
    • 1. the helix unwinds and the two strands unzip
    • 2. DNA polymerase pairs new nucleotides to each individual DNA strand matich A with T and C with G.
    • 3. The end result is 2 molecules of DNA
  29. What enzyme is involved in DNA replication?
    DNA Polymerase
  30. Is there any difference in the DNA found in different cells of the human body?
    No, just different parts of the DNA are being read
  31. What is PCR?
    • Polymerase Chain Reaction
    • a laboratory technique used to replicate, and thus ampify, a specific DNA segment
  32. Describe the steps of PCR.
    • 1. Heating- separates DNA strands
    • 2. Cooling- Allows DNA polymerase to pair new nucleotides with the original template strand
  33. What are the "ingredients" required for PCR?
    • -DNA
    • -Nucleotides A,T,C,G
    • -DNA polymerase
    • -Primers
  34. Describe the stpes in running a gel.
    • 1. Collect cells and extract DNA from the crime scene evidence.
    • 2. PCR amplify multiple STR regions
    • 3. Separate STR's using gel electrophoresis
  35. Why does DNA move through the gel?
    because it has a negative charge, and therefore it moves towards the positive end of the gel.
  36. Coding regions
    Sequences of DNA that serve as instructions for making proteins
  37. Non-Coding regions
    DNA sequences that do not hold instructions to make protein
  38. Are coding or non-coding regions more variable?
    Non-coding sequences vary much more between individuals
  39. Which region is used in making DNA fingerprints?
    STR (Short Tandem Repeat) Regions
  40. How many chromosomes are found in haploid cells?
  41. How many chromosomes are found in diploid cells?
  42. Binary fission
    A type of asexual reproduction in which one parental cell divides into two
  43. Population
    a group of organisms of the same species living together in the same geographic area
  44. Evolution
    Chance in allele frequencies in a population over time
  45. Fitness
    The relative ability of an organism to survive and reproduce in a particular environment
  46. Natural Selection
    Differential survival and reproduction of individuals in response to environmental pressure that leads to chance in allele frequencies in a population over time
  47. Adaptation
    The response of a population to environmental pressure, so that advantageous traits become more common in the population over time
  48. Directional selection
    Occurs when a single phenotype predominates in a paticular environment
  49. Stabilizing selection
    occurs when phenotypes at each end of the spectrum are less suited to the environment than organisms in the middle of the phenotypic range
  50. Diversifying selection
    Tupically occurs in a "patchy" environment, in which extremes of the phenotypic range do better than middle range individuals
Card Set:
BIO 100 EXAM 2
2011-10-14 23:11:34

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