bio 214 exam IV

Card Set Information

bio 214 exam IV
2014-04-28 21:57:38
cell biology

exam 4
Show Answers:

  1. Two complementary nucleotides in an RNA or a DNA molecule that are held together by hydrogen bonds—for example, G with C, and A with T or U.
    base pair
  2. The orderly sequence of events by which a cell duplicates its contents and divides into two.
    cell cycle
  3. Specialized DNA sequence that allows duplicated chromosomes to be separated during M phase; can be seen as the constricted region of a mitotic chromosome.
  4. Complex of DNA and proteins that makes up the chromosomes in a eukaryotic cell.
  5. Enzyme (typically multisubunit) that uses the energy of ATP hydrolysis to alter the arrangement of nucleosomes in eukaryotic chromosomes, changing the accessibility of the underlying DNA to other proteins, including those involved in transcription.
    chromatin-remodeling complex
  6. Describes two molecular surfaces that fit together closely and form noncovalent bonds with each other. Examples include complementary base pairs, such as A and T, and the two complementary strands of a DNA molecule.
  7. The typical structure of a DNA molecule in which the two complementary polynucleotide strands are wound around each other with base-pairing between the strands.
    double helix
  8. One of the two main states in which chromatin exists within an interphase cell. Prevalent in gene-rich areas, its less compact structure allows access for proteins involved in transcription. (See alsoheterochromatin.)
  9. Unit of heredity containing the instructions that dictate the characteristics or phenotype of an organism; in molecular terms, a segment of DNA that directs the production of a protein or functional RNA molecule.
  10. The process by which a gene makes a product that is useful to the cell or organism by directing the synthesis of a protein or an RNA molecule with a characteristic activity.
    gene expression
  11. Highly condensed region of an interphase chromosome; generally gene-poor and transcriptionally inactive.
  12. One of a group of abundant highly conserved proteins around which DNA wraps to form nucleosomes, structures that represent the most fundamental level of chromatin packing.
  13. An ordered display of the full set of chromosomes of a cell arranged with respect to size, shape, and number.
  14. Large structure within the nucleus where ribosomal RNA is transcribed and ribosomal subunits are assembled.
  15. Beadlike structural unit of a eukaryotic chromosome composed of a short length of DNA wrapped around a core of histone proteins; includes a nucleosomal core particle (DNA plus histone protein) along with a segment of linker DNA that ties the core particles together.
  16. Nucleotide sequence at which DNA replication is initiated.
    replication origin
  17. Repetitive nucleotide sequence that caps the ends of linear chromosomes. Counteracts the tendency of the chromosome otherwise to shorten with each round of replication.
  18. The genetic transmission of traits from parents to offspring.
  19. Enzyme that removes acetyl groups from lysines present in histones; its action often allows chromatin to pack more tightly.
    histone deacetylase
  20. State in which a eukaryotic chromosome exists when the cell is between divisions; more extended and transcriptionally active than mitotic chromosomes.
    interphase chromosome
  21. Highly condensed duplicated chromosome in which the two new chromosomes (also called sister chromatids) are still held together at the centromere. The structure chromosomes adopt during mitosis.
    mitotic chromosome
  22. Enzyme that reseals nicks that arise in the backbone of a DNA molecule; in the laboratory, can be used to join together two DNA fragments.
    DNA ligase
  23. Collective term for the enzymatic processes that correct deleterious changes affecting the continuity or sequence of a DNA molecule.
    DNA repair
  24. The process by which a copy of a DNA molecule is made.
    DNA replication
  25. Mechanism by which double-strand breaks in a DNA molecule can be repaired flawlessly; uses an undamaged, duplicated, or homologous chromosome to guide the repair. During meiosis, the mechanism results in an exchange of genetic information between the maternal and paternal homologs.
    homologous recombination
  26. At a replication fork, the DNA strand that is made discontinuously in short separate fragments that are later joined together to form one continuous new strand.
    lagging strand
  27. At a replication fork, the DNA strand that is made by continuous synthesis in the 5′-to-3′ direction.
    leading strand
  28. Mechanism for recognizing and correcting incorrectly paired nucleotides—those that are noncomplementary
    mismatch repair
  29. A randomly produced, permanent change in the nucleotide sequence of DNA.
  30. A quick-and-dirty mechanism for repairing double-strand breaks in DNA that involves quickly bringing together, trimming, and rejoining the two broken ends; results in a loss of information at the site of repair.
    nonhomologous end joining
  31. Short length of DNA produced on the lagging strand during DNA replication. Adjacent fragments are rapidly joined together by DNA ligase to form a continuous DNA strand.
    Okazaki fragment
  32. An RNA polymerase that uses DNA as a template to produce an RNA fragment that serves as a primer for DNA synthesis.
  33. The process by which DNA polymerase corrects its own errors as it moves along DNA.
  34. Y-shaped junction that forms at the site where DNA is being replicated.
    replication fork
  35. Enzyme that elongates telomeres, synthesizing the repetitive nucleotide sequences found at the ends of eukaryotic chromosomes.
  36. A molecular structure that serves as a pattern for the production of other molecules. For example, one strand of DNA directs the synthesis of the complementary DNA strand.
  37. Enzyme that reseals nicks that arise in the backbone of a DNA molecule; in the laboratory, can be used to join together two DNA fragments.
  38. In DNA replication, a short length of RNA made at the beginning of the synthesis of each DNA fragment; these RNA segments are subsequently removed and filled in with DNA.
  39. Process in which an exchange of genetic information occurs between two chromosomes or DNA molecules. Enzyme-mediated recombination can occur naturally in living cells or in a test tube using purified DNA and enzymes that break and re-ligate DNA strands.
  40. The production of different mRNAs (and proteins) from the same gene by splicing its RNA transcripts in different ways.
    alternative splicing
  41. During protein synthesis, an enzyme that attaches the correct amino acid to a tRNA molecule to form a “charged” aminoacyl-tRNA.
    aminoacyl-tRNA synthetase
  42. Set of three consecutive nucleotides in a transfer RNA molecule that recognizes, through base-pairing, the three-nucleotide codon on a messenger RNA molecule; this interaction helps to deliver the correct amino acid to a growing polypeptide chain.
  43. Group of three consecutive nucleotides that specifies a particular amino acid or that starts or stops protein synthesis; applies to the nucleotides in an mRNA or in a coding sequence of DNA.
  44. Segment of a eukaryotic gene that is transcribed into RNA and dictates the amino acid sequence of part of a protein.
  45. Proteins that assemble on the promoters of many eukaryotic genes near the start site of transcription and load the RNA polymerase in the correct position.
    general transcription factors
  46. Special tRNA that initiates the translation of an mRNA in a ribosome. It always carries the amino acid methionine.
    initiator tRNA
  47. Noncoding sequence within a eukaryotic gene that is transcribed into an RNA molecule but is then excised by RNA splicing to produce an mRNA.
  48. RNA molecule that specifies the amino acid sequence of a protein.
    messenger RNA (mRNA)
  49. The addition of multiple adenine nucleotides to the 3′ end of a newly synthesized mRNA molecule.
  50. DNA sequence that initiates gene transcription; includes sequences recognized by RNA polymerase.
  51. Enzyme that degrades proteins by hydrolyzing their peptide bonds.
  52. Large protein machine that degrades proteins that are damaged, misfolded, or no longer needed by the cell; its target proteins are marked for destruction primarily by the attachment of a short chain of ubiquitin.
  53. One of the three possible ways in which a set of successive nucleotide triplets can be translated into protein, depending on which nucleotide serves as the starting point.
    reading frame
  54. RNA molecule that forms the structural and catalytic core of the ribosome.
    ribosomal RNA (rRNA)
  55. An RNA molecule with catalytic activity.
  56. The modification of the 5′ end of a maturing RNA transcript by the addition of an atypical nucleotide.
    RNA capping
  57. Enzyme that catalyzes the synthesis of an RNA molecule from a DNA template using nucleoside triphosphate precursors.
    RNA polymerase
  58. Broad term for the modifications that a precursor mRNA undergoes as it matures into an mRNA. It typically includes 5′ capping, RNA splicing, and 3′ polyadenylation.
    RNA processing
  59. Process in which intron sequences are excised from RNA molecules in the nucleus during the formation of a mature messenger RNA.
    RNA splicing
  60. RNA molecule produced by transcription that is complementary to one strand of DNA.
    RNA transcript
  61. Hypothetical period in Earth’s early history in which life-forms were thought to use RNA both to store genetic information and to catalyze chemical reactions.
    RNA world
  62. RNA molecule of around 200 nucleotides that participates in RNA splicing.
    small nuclear RNA (snRNA)
  63. Large assembly of RNA and protein molecules that splices introns out of pre-mRNA in the nucleus of eukaryotic cells.
  64. Process in which RNA polymerase uses one strand of DNA as a template to synthesize a complementary RNA sequence.
  65. Small RNA molecule that serves as an adaptor that “reads” a codon in mRNA and adds the correct amino acid to the growing polypeptide chain.
    transfer RNA (tRNA)
  66. Process by which the sequence of nucleotides in a messenger RNA molecule directs the incorporation of amino acids into protein.
  67. Protein that promotes the proper association of ribosomes with mRNA and is required for the initiation of protein synthesis.
    translation initiation factor
  68. The principle that genetic information flows from DNA to RNA to protein.
    central dogma
  69. Protein that promotes the proper association of ribosomes with mRNA and is required for the initiation of protein synthesis.
    initiation factor
  70. Messenger RNA molecule to which multiple ribosomes are attached and engaged in protein synthesis.
  71. Degradation of a protein by means of a protease.
  72. Complex made of RNA and protein that recognizes RNA splice sites and participates in the chemistry of splicing; together these complexes form the core of the spliceosome.
    small nuclear ribonucleoprotein (snRNP)
  73. Term loosely applied to any protein required to initiate or regulate transcription in eukaryotes. Includes transcription regulators as well as the general transcription factors.
    transcription factor
  74. The ability of differentiated cells and their descendants to maintain their identity.
    cell memory
  75. Describes the way in which groups of transcription regulators work together to regulate the expression of a single gene.
    combinatorial control
  76. Process by which a cell undergoes a progressive, coordinated change to a more specialized cell type, brought about by large-scale changes in gene expression.
  77. The enzymatic addition of methyl groups to cytosine bases in DNA; this covalent modification generally turns off genes by attracting proteins that block gene expression.
    DNA methylation
  78. The transmission of a heritable pattern of gene expression from one cell to its progeny that does not involve altering the nucleotide sequence of the DNA.
    epigenetic inheritance
  79. Somatic cell that has been reprogrammed to resemble and behave like a pluripotent embryonic stem (ES) cell through the artificial introduction of a set of genes encoding particular transcription regulators.
    induced pluripotent stem cell (iPS cell)
  80. Class of RNA molecules more than 200 nucleotides in length that does not encode proteins.
    long noncoding RNA
  81. Small noncoding RNA that controls gene expression by base-pairing with a specific mRNA to regulate its stability and its translation.
    microRNA (miRNA)
  82. Cell capable of giving rise to any of the specialized cell types in the body.
    pluripotent stem cell
  83. An important form of regulation in which the end product of a reaction or pathway stimulates continued activity; controls a variety of biological processes, including enzyme activity, cell signaling, and gene expression.
    positive feedback loop
  84. Regulation of gene expression that occurs after transcription of the gene has begun; examples include RNA splicing and RNA interference.
    post-transcriptional control
  85. DNA sequence to which a transcription regulator binds to determine when, where, and in what quantities a gene is to be transcribed into RNA.
    regulatory DNA sequence
  86. RNA molecule that plays a role in controlling gene expression.
    regulatory RNA
  87. Gene encoding a protein whose activity is easy to monitor experimentally; used to study the expression pattern of a target gene or the localization of its protein product.
    reporter gene
  88. Cellular mechanism activated by double-stranded RNA molecules that results in the destruction of RNAs containing a similar nucleotide sequence. It is widely exploited as an experimental tool for preventing the expression of selected genes (gene silencing).
    RNA interference (RNAi)
  89. Short length of RNA produced from double-stranded RNA during the process of RNA interference. It base-pairs with identical sequences in other RNAs, leading to the inactivation or destruction of the target RNA.
    small interfering RNA (siRNA)
  90. Protein that binds specifically to a regulatory DNA sequence and is involved in controlling whether a gene is switched on or off.
    transcription regulator
  91. A protein that binds to a specific regulatory region of DNA to permit transcription of an adjacent gene.
    transcriptional activator
  92. A protein that binds to a specific regulatory region of DNA to prevent transcription of an adjacent gene.
    transcriptional repressor
  93. A protein that binds to a specific regulatory region of DNA to permit transcription of an adjacent gene.
  94. Regulatory DNA sequence to which transcription regulators bind, influencing the rate of transcription of a gene that may be many thousands of base pairs away.
  95. A protein that binds to a specific regulatory region of DNA to prevent transcription of an adjacent gene.
  96. In bacteria, a transcription regulator that, in the presence of tryptophan, shuts off production of the tryptophan biosynthetic enzymes by binding to the promoter region that controls expression of those genes.
    tryptophan repressor