Bio 172 Exam 4 Prep

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nextMD
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118775
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Bio 172 Exam 4 Prep
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2011-11-29 12:44:45
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Bio 172
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Questions to prepare for Exam 4
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  1. What are the G1 checkpoints?
    • cell size is adequate
    • nutrients are sufficient
    • social signals are present
    • DNA is undamaged
  2. What are the G2 checkpoints?
    • chromosomes have replicated successfully
    • DNA is undamaged
    • activated MPF is present
  3. What are the Metaphase checkpoints?
    all chromosomes are attached to mitotic spindle apparatus
  4. Start Codon
    AUG - Met
  5. Stop Codon
    • UAA
    • UAG
    • UGA
  6. What is P53?
    Tumor Suppressor
  7. What is PDGF?
    Platelet Derived Growth Factor:

    • Signal for cell division
    • promotes wound healing
  8. Cancerous cells have two types of defects:
    • defects that make proteins required for cell growth active when they shouldn't be.
    • defects that prevent tumor suppressor genes from shutting downt the cell cycle.
  9. What is Rb protein?
    a tumor suppressor gene, binds to E2F and inactivates it
  10. What happens if the sister chromatids of one chromosome fail to separate at anaphase?
    One daughter cell receives too few chromosomes; the other receives a replicated chromosome.
  11. The Genetic Code has 4 important properties:
    • Redundant - all amino acids coded by more than one codon
    • Unambiguous - a single codon never codes for more than one amino acid
    • Nearly Universal - All codons specify the same amino acids in all organisms
    • Conservative - The first two bases in codons that specify the same amino acid, are always identical.
  12. RNA and DNA is always synthesized in the ___________ direction.
    5' to 3'
  13. Which mutation changes nucleotide, but does not change amino acid specified by codon?
    Silent
  14. Which mutation changes nucleotide that changes amino acid specified by a codon?
    Missense
  15. Which mutation changes a nucleotide that results in early stop codon?
    Nonsense
  16. Which mutation is defined by an addition or deletion of a nucleotide?
    Frameshift
  17. When segments become flipped and rejoin, it is known as _______________.
    Inversion
  18. When segments become attached to a different chromosome, it is known as _________________.
    Translocation
  19. What are two exceptions to Central Dogma?
    • Many genes code for RNA molecules that do not function as mRNA's - they are not translated into proteins.
    • In some cases, info flows from RNA back to DNA.
  20. How many amino acids are represented in the genetic code by just one codon?
    2 : Methionine and Tryptophan
  21. How many different amino acids would be found in a polypeptide made from translation of an RNA containing only cytosines (C) and adenines (A) in random order?
    8 is the number of POSSIBLE codons, but only 6 are different.
  22. What is the most common number of codons that specifies a single amino acid?
    two
  23. What is a tetrad?
    4 chromatids from homologous chromosomes
  24. Meiosis - What happens in Interphase?
    Chromosomes replicate in parent cell, in uncondensed state, forming sister chromatids.
  25. Meiosis - What happens in Early Prophase I?
    • chromosomes condense
    • nuclear envelope breaks up
    • spindle apparatus forms
    • synapsis of homologous chromosomes.
  26. Meiosis - What happens in Late Prophase I?
    Crossing over of non-sister chromatids
  27. Meiosis - what is Chiasma?
    an x shaped structure caused by each crossover
  28. Meiosis - What happens in Metaphase I?
    Migration of tetrads to metaphase plate is complete
  29. Meiosis - What happens in Anaphase I?
    Homologs separate and begin moving to opposite sides of cell
  30. Meiosis - What happens in Telophase I and Cytokinesis?
    • Chromosomes move to opposite sides of cell
    • then cell divides
  31. Meiosis - What happens in Prophase II?
    • There is no interphase between I and II.
    • Spindle apparatus forms.
  32. Meiosis - What happens in Methaphase II?
    Chromosomes line up at the middle of the cell (metaphase plate)
  33. Meiosis - What happens in Anaphase II?
    Sister chromatids separate, begin moving to opposite sides of cell
  34. Meiosis - What happens in Telophase II and Cytokinesis?
    • Chromosomes move to opposite sides of cell
    • then cell divides
  35. What is crossing over?
    • The process of chromosome exchange.
    • Takes place during Late Prophase I.
  36. Mitosis - What happens in Interphase?
    • After chromosome replication, each chromosome is composed of two sister chromatids.
    • Chromosomes have replicated.
  37. Mitosis - What happens in Prophase?
    • Chromsomes condense
    • Spindle apparates begins to form
  38. Mitosis - What happens in Prometaphase?
    • Nuclear envelope breaks down
    • Kinetochore microtubues contact chromosomes at kinetochore
  39. Mitosis - What happens in Metaphase?
    Chromosomes complete migration to middle of cell.
  40. Mitosis - What happens in Anaphase?
    • Sister chromatids separate
    • Chromosomes are pulled to opposite poles of the cell
  41. Mitosis - What happens in Telophase?
    • The nuclear envelope re-forms
    • Spindle apparatus disintegrates
  42. What event of Meiosis makes meiosis a reduction division, unlike mitosis?
    During Anaphase I, homologs (not sister chromatids, as in mitosis) are separated, making the cel products of meiosis I haploid.
  43. What are homologous chromosomes?
    Chromosomes that are similar in their size, shape, and gene content.
  44. What is a tetrad?
    A group of four chromatids produced when homologs synapse.
  45. Meiosis II is similar to which process?
    Mitosis in haploid cells.
  46. What is synapsis?
    The process of homologous chromosomes pairs coming together.
  47. What is the end result of meiosis and subsequent fertilization of gametes?
    an offspring with a chromosome complement unlike that of either parent
  48. What information can not be obtained from an individual's karyotype?
    • The sequence of bases of a particular gene
    • Karyotype is the study of the number and types of chromosomes present.
  49. What is the composition of a tetrad at the beginning of prophase I?
    • One pair of homologous chromosomes
    • The tetrad is made up of two chromosomes, not four.
  50. Name Five Essential Developmental Processes:
    • Cell Proliferation
    • Programmed cell death
    • Cell movement or differential expansion
    • Cell differentiation
    • Cel-cell interactions
  51. What is totipotent?
    • (all powerful) cells that can de-differentiate and then differentiate to from neded cells.
    • Only occur in plants.
  52. What is responsible for differentiation?
    • Transcriptional control
    • In eukaryotes, transcription is controlled primarily by the presence of regulatory transcription factors.
  53. Cells become specialized because they _________________ different genes.
    express
  54. Do Meristematic cells and stem cells differentiate?
    No, but they continue proliferating throughout life.
  55. What is homeosis?
    • (Like-Condition). Homeosis occurs when cells get incorrect information about where they are in the body.
    • Replacement of one structure by another structure
    • Structure develops in the wrong location
  56. What are homeotic genes?
    • homeotic genes regulate effector genes
    • homeotic gene products identify each segment's structural role
    • hox genes are homeotic genes
  57. What is the function of stem cells in adult mammals?
    They produce cells that differentiate to replace dead or damaged cells.
  58. What is a homeotic mutant?
    An individual with a structure located in the wrong place.
  59. Gastrulation is marked by which of the four essential developmental processes?
    cell movement
  60. What process marks the initiation of cell differentiation?
    Cells initiate differential gene expression.
  61. Which of the following processes is the most important level of control over gene expression?
    transcriptional regulation
  62. What similarities are found when comparing the homeotic genes of Drosophilaand the Hox genes of the mouse?
    • genes are expressed in a similar head-to-tail pattern
    • they are in the same order on the chromosome
    • mutation of the genes in either organism causes homeosis.
  63. What is central dogma?
    • summarizes the flow of information in cells.
    • DNA (info storage) to RNA (info carrier) to proteins (active cell machinery)
  64. Name 2 examples of Ectoderm Layer:
    • Epidermis of Skin
    • Nervous System
  65. Name 2 examples of Mesoderm Layer:
    • Muscular System
    • Reproductive System
    • Skeletal System
  66. Name 2 exaples of Endoderm Layer:
    • Thyroid
    • Liver
    • Pancreas

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