BIO Final pt 1

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BIO Final pt 1
2012-05-07 02:02:19

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  1. DNA?
    substance of inheritance
  2. DNA made up of?
    nucleic acids are unique in their ability to direct their own replication from monomers
  3. DNA replication?
    process by which a DNA molecule is copied & how cells repair their DNA
  4. Chromosomes?
    DNA & proteins
  5. Watson & Crick?
    1953-created double-helical model for the structure of DNA
  6. pathogenic?
    disease causing
  7. non-pathogenic?
  8. Genetic trait of pathogenicity be transferred btwn bacteria?
    • Griffith
    • yes=>bacterial transformation
    • result: when killed pathogenic bacteria w/heat & then mixed all remains w/ living bacteria of non-pathogenic strain, becomes pathogenic
  9. Griffith?
    • 1928
    • discovery of the genetic role of DNA
    • study Streptococcus pneumonae(bacterium)=> 2 strains:
    • 1 pathogenic(disease causing)
    • 1 non-pathogenic(harmless)
    • more evidence tht DNA is genetic material
  10. transformation?
    change in genotype & phenotype due to the assimilation of external DNA by a cell
  11. bacteriophages?
    • viruses
    • "bacteria-eaters"
    • AKA phages
  12. Virus?
    • little more than DNA
    • sometimes RNA
    • enclosed by a protective coat => protein
  13. Chase & Hershey?
    • performed experiment showing that DNA is the genetic material of a phage
    • T2 (E.Coli) => injected w/ radioactive isotope: P & S
    • P=> DNA(only)
    • S=>protein (only)
    • IMPT: provided evidence tht nucleic acids rather then proteins are hereditary material
  14. Chagraff?
    • 1: base composition varies btwn species
    • 2: w/in a species, # of A-T base are equal & C-G base are equal
    • A=T (2 H bonds)
    • C=G (3 H bonds)
  15. Wilkins & Franklin ?
    produced X-ray diffraction of DNA
  16. double helix?
    presence of 2 strands accounts
  17. Key features of DNA structure?
    • sugar PO4 backbones of the 2 strands
    • held by H bonds btwn nitrogenous bases (paired in the interior of helix)
    • antiparallel
  18. partial chemical structure?
    strong covalent bonds link units of ea. strand while weaker H bonds hold one strand to the other
  19. antiparallel?
    oriented in opposite directions
  20. Purines?
    A & G
  21. Pyrimidines?
    C & T
  22. Purine + Purine?
    too wide
  23. Pyrimidine + Pyrimidine?
    too narrow
  24. Purine + Pyrimidine?
    width is uniform diameter
  25. DNA pairing - template strand?
    2 strands: complementary -> ea. store the info necessary to reconstruct the other
  26. Semiconservative model?
    both daughter molecule will consist of 1 intact parent & 1 newly synthesized strand
  27. Conservative model?
    2 parental strands while other daughter molecule will consis of 2 newly synthesized strands
  28. Dispersive model?
    daughter molecule contains a mixture of old & new DNA
  29. Messelson & Stahl?
    • experiment supported the semiconservative model of DNA replication
    • 3 models
  30. Origins of replication?
    replication of DNA molecule -> short stretches of DNA having a specific sequence of nucleotides
  31. replication fork?
    Y-shaped region where parental strands of DNA are being unwound
  32. helicases?
    enzymes that participate in the unwinding -> untwist the double-helix at the replication forks, separating the 2 parental strands & making them available as template strands
  33. single strand binding proteins?
    bind to the unpaired DNA strands keeping them from re-pairing
  34. topoisomerase?
    relieves the strain of twisting by breaking, swiveling & rejoining DNA strands
  35. RNA chain?
    Primer synthesized by enzyme primase
  36. Nitrogenous bases of DNA?
    • T -> thymine
    • A-> adenine
    • C->cytosine
    • G->guanine
    • along w/ 5 C-sugar=> deoxyribose (covalently bonded)
  37. nitrogenous base T?
  38. nitrogenous base A?
  39. nitrogenous base C?
  40. nitrogenous base G?
  41. 5-C sugar?
    • deoxyribose
    • covalently bonded
  42. very critical to DNA structure?
    • 1" prime...
    • phosphate (PO4)
  43. nucleotide? (nucleic acid?
    sugar + nitrogenous bases + P
  44. Avery?
    • 1944
    • focused on 3 mains:
    • 1)DNA
    • 2)RNA
    • 3)protein
    • transforming agent -> DNA
  45. Phage head is made up of...?
  46. cytosine makes up 38% of the nucleotides in a sample of DNA from an organism...percentage of nucleotides in this sample would be thymine..?
  47. What also holds the bonds btwn stacked pairs of DNA?
    Van der Waals interactions
  48. What is function of DNA polymerase III?
    add nucleotides to end of a growing DNA strand
  49. New DNA strand elongates only in the 5' to 3' direction b/c..?
    DNA polymerase can only add nucleotides to the free 3' end
  50. 3' prime end?
    always OH group
  51. 5' prime end?
    always PO4 group
  52. Transfer RNA(#1) attached to amino acid lysine enters ribosome, and binds to growing peptide on the other tRNA(#2) in ribosome already..where does tRNA(#2) move to after this bonding of lysine to the polypeptide?
    E site
  53. Sickle cell disease is result of what kind of mutation?
  54. Which point mutation would most likely have a catastrophic effect on functioning of a protein?
    base deletion near the start of a gene
  55. What to expect of a eukaryotic cell lacking telomerase?
    reduction in chromosome length
  56. Transfer RNA(#1) attached to amino acid lysine enters ribosome, and binds to growing peptide on the other tRNA(#2) in ribosome already..when ribosome reaches a stop codon on mRNA, no corresponding tRNA enters A site..if translation reaction were to be experimentally stopped, which would u isolate?
    assembled ribosome w/ a polypeptide attached to tRNA in P site
  57. Particular triplet of bases in the nontemplate strand of DNA is AAA...anticodon in tRNA tht binds to mRNA codon is..??
  58. What is meant by description of "antiparallel" regarding strands tht make up DNA?
    5' to 3' direction of 1 strand runs counter to the 5' to 3' direction of the other strand
  59. RNA polymerase moves in which direction along DNA?
    3'->5' along template strand
  60. Protein synthesis sequence..?
    • 1) small ribosomal subunit binds w/ mRNA
    • 2) aminoacyl-tRNA binds to A site
    • 3) peptide bond forms btwn new amino acid & polypeptide chain
    • 4) tRNA translocates to P site
    • 5) tRNA leaves P site, & P site remains vacant
  61. RNA polymerase differs from DNA polymerase?
    RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis
  62. put this in framshift mutation?
  63. Synthesis of lagging strand?
    Each Okazaki fragment on lagging strand must be primed separately (1&4)
  64. DNA polymerase III?
    • forms Okazaki fragments
    • elongates each Okazaki fragement adding on to its primer
    • leading strand: continuously synthesizes the leading strand, adding on to the primer
  65. DNA polymerase I?
    • aka "proof reading" or backfilling w. DNA from RNA
    • leading strand: removes primer from the 5' end of leading strand & replaces it w/ DNA on the adjacent 3' end
    • Lagging strand: removes the primer from the 5' end of ea. fragment & replaces it w/ DNA, adding on to the 3'end of adjacent fragment
  66. DNA ligase?
    • fills in (seals) all spots on lagging base
    • leading strand: joins the 3'end of DNA tht replaces the primer to the rest of the leading strand
    • lagging: joins the Okazaki fragments
  67. Helicase?
    • cuts H bonds
    • cause to unwind
  68. SSBP?
    single strand binding protein
  69. Topoisomerase?
    hepls to unwind & not get it tight
  70. Steps of DNA replication?
    • 1) helicase
    • 2) SSBP
    • 3)topoisomerase
    • 4) primase (RNA polymerase)
    • 5) DNA polymerase III
    • 6)DNA polymerase I
    • 7) Ligase
  71. Progeria?
    • genetic defect
  72. Gene expression?
    process by which DNA directs the synthesis of proteins
  73. Genes?
    provide the instructions for making specific proteins
  74. Transcription?
    • any kind of RNA on a DNA template
    • actual synthesis of RNA under the direction of DNA
    • produces mRNA
  75. mRNA?
    • carries a genetic message from the DNA to the protein
    • synthesizing machinery of the cell
  76. Gene to Protein?
    • DNA ----> RNA ------> proteins
    • (transcripts) (translation) (gene product)
    • mRNA->rRNA->tRNA message of DNA to protein
    • self-replication

    • rRNA=>ribosomal
    • tRNA=>transfer
  77. Translation?
    • actual sunthesis of a polypeptide, which occurs under the direction of mRNA
    • occurs on ribosomes
  78. single stranded?
    • Uracil substitutes for T (except for T w/ A it will be U)
    • ribose sugar
    • RNA polymerase
  79. Only find U in...?
  80. Prokaryotes?
    • translation & transcription occurs together
    • DNA is not separated by nuclear membranes from ribosomes & other proteins -synthesizing
    • lacks nucleus
    • mRNA produced by transcription is immediately translated w/o add. processing
  81. Eukaryotes?
    • RNA transcripts are modified before becoming true mRNA
    • nuclear envelope separates transcription from translation in space/time
    • transcription occurs=> nucleus
    • translation occurs=> cytoplasm
  82. How many bases corresponds to amino acid?
  83. Genetic info..?
    encoded as sequence of nonoverlapping base triplets, or codons
  84. Triplets of nucleotide bases?
    smallest units of uniform length tht can code for all amino acids
  85. triplet code?
    genetic instruction for a polypeptide chain are written in the DNA as a series of codons
  86. Codon in mRNA..?
    • is either translated into amino acid or serves as a translational stop signal
    • 3rd base in sequence
  87. RNA synthesis?
    • catalyzed by RNA polymerase which pries the DNA strands apart & hooks together the RNA nucleotides
    • follows same base-pairing rules as DNA, except tht in RNA U subs for T
  88. stages of transcript??
    • 1) initiation
    • 2) elongation
    • 3) termination
  89. promoter?
    • DNA sequence where RNA polymerase attaches & initiates transcription
    • signals the intiation of RNA synthesis
  90. transcription unit?
    • stretch of DNA tht is transcribed into RNA molecules
    • helps eukaryotic RNA polymerase recognize promoter sequence
  91. Elongation of RNA strand..?
    RNA polymerase moves along DNA, continues to untwist double helix, exposing 10-20 DNA bases at a time for pairing w/ RNA nucleotides
  92. Alteration of mRNA ends..?
    • ea. end of pre-mRNA mol. is modified in particular way:
    • 5'end receives a modified nucleotide cap
    • 3'end gets poly-A tail
  93. RNA splicing?
    removes introns & joins exons
  94. Are molecules of tRNA all the same?
    • NO!
    • each carries specific amino acid on 1 end
    • each has an anitcodon on other end
  95. tRNA molecule?
    • consists of single RNA strand tht is only about 80 nucleotides long
    • L-shaped
  96. aminoacyl-tRNA synthase?
    • specific enzyme
    • joins each amino acid to correct tRNA
  97. Ribosome has 3 binding sites for tRNA..?
    • 1)P site
    • 2) A site
    • 3) E site
  98. P site?
    • binding site
    • aka Peptidyl-tRNA
  99. A site?
    • Aminoacyl-binding site
    • starts & active
  100. E site?
    Exit site
  101. 3 stages of translation?
    • 1) initiation ->w/AUG
    • 2) elongation -> gets longer & longer
    • 3) termination -> protein
  102. Mutation?
    changes in the genetic material of cell
  103. point mutations?
    changes in just one base pair of gene
  104. Types of point mutations?
    • base-pair substitutions => replacement of 1 nucleotide & its partner w/another pair of nucelotide
    • base-pair insertions or deletions => result in frameshift
  105. Cell division?
    • continuity of life is based on the reproduction of cells
    • integral part of cell cycle
  106. cell cycle?
    life of a cell from time it first formed from a dividing parent cell until its own division into 2 daughter cells
  107. Organisms depend on cell division for..?
    • development from a fertilized cell (reproduction)
    • growth
    • repair (aka tissue renewal)
  108. Cell division results from..?
    • daughter cells w/ identical genetic info-> DNA
    • except meiosis
  109. special type of cell division tht produce sperm/eggs?
  110. Genome?
    • all DNA in cell constitutes this
    • consist of single DNA molecule or # of DNA molecules
  111. Chromosomes?
    • DNA molecules in cell are packages into this
    • replication/distribution of so much DNA is manageable
  112. Somatic cells?
    • nonreproductive cells
    • 2 sets of chromosomes (46 chromosomes ->2 sets of 23 ea.parent)
  113. gametes?
    • reproductive cells =>sperm & eggs
    • have half as many chromosomes as somatic cells
    • 1 set of chromosomes
  114. chromatin?
    • eukaryotic cells consists of this
    • complex of DNA & protein tht condenses during cell division
    • building material of chromosomes
  115. Cell divison consists of...?
    • Mitosis
    • Cytokinesis
  116. Mitosis?
    division of nucleus
  117. cytokinesis?
    division of the cytoplasm
  118. Meiosis?
    • gametes are produced by variation of cell division
    • yields nonidentical daughter cells tht have only 1 set of chromosomes, half as many as parent cell
  119. Cell cycle ?
    • mitotic (M) phase
    • Interphase
  120. Mitotic (M) phase?
    • mitosis & cytokinesis
    • shortest part of cycle
  121. Interphase?
    • cell growth & copying of 90% of chromosomes in preparation for cell division
    • longer part of cycle
    • cell is about to divide, grows& copies its chromosomes in preparation for cell division
    • divided into subphases:
    • 1)G1 phase ("1st gap")
    • 2)S phase("synthesis")
    • 3)G2 phase ("2nd gap")
  122. cell duplicated during which phase?
    S phase
  123. Mitosis is divided into 5 phases?
    • prophase
    • prometaphase
    • metaphase
    • anaphase
    • telophase
  124. mitotic spindle?
    composed of centrosomes & the microtubules that extend from them
  125. asters?
    radial arrays of shorter microtubules tht extend from centrosomes
  126. centrosomes?
    • regions in animal's cells tht organize the microtubules of spindle
    • contains 2 centrioles
  127. G2 of interphase?
    • nucleur envelope encloses nucleus
    • nucleus=>1 or more nucleoli
    • 1 centrosomes have formed by duplication of single centrosome
    • chromosomes=>duplicated during S phase, can't be seen individually b/c not condensed
  128. Prophase?
    • chromatin fibers become more tightly coiled->discrete chromosomes
    • nucleoli disappear
    • 2 identical sister chromatids joined at their centromeres (cohesins)
    • mitotic spindle being to form
    • centromeres move away from ea. other ->propelled by microtubules
  129. prometaphase?
    • nuclear envelope fragments
    • microtubules extending from ea. centrosome can now invade nuclear area
    • chromosomes=>more condensed
    • ea.2 chromatids have kinetochore
    • some of microtubules attach to kinetochore
    • kinetochore microtubules->pulling back & forth like tug of war
  130. metaphase?
    • centrosomes=>opp poles of cells
    • chromosome convene @ metaphase plate
    • for ea. chromosome -kinetochore of sister chromatids are attached to kinetochore microtubules coming from opp poles
  131. cell cycle control system ?
    • similiar to a clock
    • cyclically operating set of molecules in cell that triggers & coordinates key events in cell cycle
  132. G0 phase?
    cell does not receive the go-ahead signal, exit the cycle, switching into nondividing state
  133. 2 types of regulatory proteins?
    • cyclins
    • cyclin-dependent kinases (Cdks)
  134. cyclins?
    • protein tht gets its name from its cyclically fluctuating concentration in cell
    • kinase to be active
  135. Protein kinases?
    • enzymes tht activate or inactivate other proteins by phosphorylating them
    • some give go-ahead signals @ G1 & G2 checkpoints
  136. G2 checkpoint?
    molecular control of cell cycle
  137. MPF?
    • maturation-promoting factor
    • cyclin-Cdk complex tht triggers a cell's passage past G2 checkpoint into M phase
  138. Density dependent inhibition?
    • crowded cells stop dividing
    • external signals
  139. anchorage dependence?
    • must be attached to substratum in order to divide
    • signaled to cell cycle via pathways involving plasma membrane proteins & elements of cytoskeletons linked to them
  140. What amino acid sequence will be generated based on this following mRNA condon seq?
  141. A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence NH2-phe-leu-ile-val-COOH would be..?
    3' AAA-GAA-TAA-CAA 5'

  142. Which of the results in the figure would be expected after one round of DNA replication in the presence of 14N?
  143. normal cell converted to cancerous cell by a process called..?
  144. Trait?
    physical or chemical expression of heredity
  145. homozygous?
    identical gene pairs on homologous chromosomes
  146. heterozygous?
    • non-identical gene pairs on homologous chromosomes
    • individual will be hybrid for trait in question
  147. dominant?
    • allele tht is phenotypically expressed in homozygous or heterozygous state
    • allele masks presence of recessive allele
  148. recessive?
    • allele tht is only expressed when homozygous
    • recessive trait only appears when dominant allele is absent
  149. phenotype?
    actual physical appearance/characteristic of organism
  150. genotype ?
    genetic makeup of organism based on alleles present
  151. Mendel?
    discovered basic principles of heredity by breeding garden peas in carefully planned experiments
  152. character?
    heritable feature tht varies among individuals such as flower color
  153. At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork:3' C C T A G G C T G C A A T C C 5'..
    RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?
    5' A C G U U A G G 3'
  154. Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. This suggests...?
    that the parents were both heterozygous.
  155. Two characters that produce a 9:3:3:1 phenotypic ratio in the F2 generation should have which of the following properties?
    The genes controlling the characters obey the law of independent assortment
  156. A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?
  157. Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of the cross BbTt × BBtt will have black fur and long tails?
  158. In a cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?
  159. Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies.How many genes must be responsible for these coat colors in Labrador retrievers?
  160. Drosophila (fruit flies) usually have long wings (+) but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg). If a homozygous bent wing fly is mated with a homozygous vestigial wing fly, which of the following offspring would you expect?
    All +bt +vg heterozygotes
  161. A 1:2:1 phenotypic ratio in the F2 generation of a monohybrid cross is a sign of
    incomplete dominance
  162. Which of the following is an example of polygenic inheritance?
    Skin pigmentation in humans
  163. A woman has six sons. The chance that her next child will be a daughter is
  164. Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents?
    XCXc and XCY
  165. Males are more often affected by sex-linked traits than females because
    males are hemizygous for the X chromosome
  166. Hardy-Weinberg principle?
    states that, if a population is not evolving, then the frequencies of alleles and genotypes in that population will remain constant from one generation to the next. Further, this principle allows us to predict what the genotype frequencies will be in a non-evolving population. We can conclude that a population may be evolving if its genotype frequencies differ from those predicted by the Hardy-Weinberg principle.
  167. Which of the following are basic components of the Hardy–Weinberg model?

    Frequencies of two alleles in a gene pool before and after many random matings
  168. Which of the following statements is not a part of the Hardy–Weinberg principle?
    The genotype frequencies in the offspring generation must add up to two.
  169. True or false? The Hardy–Weinberg model makes the following assumptions: no selection at the gene in question; no genetic drift; no gene flow; no mutation; random mating
  170. Which of the following evolutionary forces results in adaptive changes in allele frequencies?
  171. What genotype frequencies are expected under Hardy–Weinberg equilibrium for a population with allele frequencies of p = 0.8 and q= 0.2 for a particular gene?
    The expected genotype frequencies are 0.64, 0.32, and 0.04 for A1A1, A1A2, and A2A2, respectively
  172. Which of the following evolutionary forces could create new genetic information in a population?
  173. When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?
    the gene involved is on the X chromosome
  174. A man with Klinefelter syndrome (47, XXY) is expected to have any of the following EXCEPT
    increased testosterone.
  175. What is a nondisjunction?
    An error in cell division that causes homologous chromosomes or sister chromatids to move to the same side of the dividing cell
  176. When can nondisjunction occur?
    Nondisjunction errors can occur in meiosis I, when homologous chromosomes fail to separate, or in either mitosis or meiosis II, when sister chromatids fail to separate.
  177. Which syndrome is characterized by the XO chromosome abnormality?
    Turner syndrome
  178. What kind of cell results when a diploid and a haploid gamete fuse during fertilization?
    A triploid cell
  179. Of the following chromosomal abnormalities, which type is most likely to be viable in humans?
  180. If a diploid cell undergoes meiosis and produces two gametes that are normal, and one with n − 1 chromosomes, and one with n + 1 chromosomes, what type of error occurred?
    A nondisjunction error occurred in meiosis II, in which both sister chromatids of a chromosome migrated to the same pole of the cell.