General ---------Biology----------------------------------------------------- ------------------Online--------------------------------------- Ch. 19 Organization & Control of Eukaryotic Genomes

MT Ch. 19,“The Organization and Control of Eukaryotic Genomes.” 
26 questions selected from testbank.  (back to contents)

  1. Which of the following is an example of transcriptional control of
     gene expression? 
     a. mRNA that is stored in the cytoplasm and needs a control signal
        to initiate translation.
     b. mRNA exists for a specific time before it is degraded.
     c. There is an amplification of genes for rRNA.
     d. RNA processing occurs before mRNA exits the nucleus.
     e. Transcription factors bind to enhancer and promoter region.

  3. All of the following are potential control mechanisms for regulation
     of gene expression in eukaryotic organisms EXCEPT
     a. the degradation of mRNA.
     b. the transport of mRNA from the nucleus.
     c. the trp operon (trp=tryptophan)
     d. transcription.
     e. gene amplification.

  5. The gene that stimulates tumorogenesis in Burkitt's lymphoma is
     expressed when it is moved to chromosome 14 from chromosome 8. This
     is an example of gene expression regulated by
     a. diffusible factors.
     b. gene amplification.
     c. steroid hormones.
     d. translocation.
     e. point mutations.

  6. Gene expression in eukaryotes may depend upon
          1. the position of the gene on the chromosome.
          2. the state of the external environment.
          3. the stage of development of the organism.
     a. 1
     b. 2
     c. 3
     d. Only 1 and 3 are correct.
     e. 1, 2, and 3 are correct.
 

  8. If a cell were unable to produce histone proteins, which of the
     following would be expected?
     a. An increase in the amount of "satellite" DNA produced during
        centrifugation.
     b. Chromosomes would not form during prophase.
     c. Spindle fibers would not form during prophase.
     d. The amplification of other protein genes would compensate for the
        lack of histones.
     e. Pseudogenes would be transcribed to compensate for the decreased
        protein in the cell.

11. The processing of the RNA transcript involves
          1. the removal of introns and the splicing together of exons.
          2. the removal of exons and the splicing together of introns.
          3. the addition of a guanine cap and a poly-A tail.
          4. the attachment of introns to ribosomal RNA.
     a. 1
     b. 2
     c. 3
     d. 4
     e. Both 1 and 3 are correct.

13. Which of the following supports the statement that an organism's
     genome is plastic?
          1. The DNA in a cell carries the complete instructions for
             making the proteins for the entire organism.
          2. Only a fraction of the DNA is expressed in any one cell at a
             particular time.
          3. Certain genes may increase in number at certain times in
             some cells.
          4. Certain genes are selectively lost in some tissues of an
             organism.
     a. 1
     b. 2
     c. 3
     d. 4
     e. Both 3 and 4 support the statement.

18. Eukaryotes use all of the following as a means of controlling gene
     expression EXCEPT the
     a. binding of regulatory proteins to DNA.
     b. degradation of mRNA molecules.
     c. processing of the mRNA transcript before it can be transcribed.
     d. modification of the amino acid sequence of a protein after it has
        been translated.
     e. modification of the RNA nucleotides to enhance transcription.

 19. Which of the following events is necessary for the production of a
     full-blown malignant tumor? 
          1. activation of an oncogene in the cell
          2. the inactivation of tumor suppressor genes within the cell
          3. the presence of mutagenic substances within the cell's
             environment
          4. the presence of a retrovirus within the cell
     a. 1
     b. 2
     c. 3
     d. 4
     e. Both 1 and 2 are necessary.

 20. Which of the following statements concerning proto-oncogenes is
     FALSE?
     a. They code for proteins associated with cell growth.
     b. They are similar to oncogenes found in retroviruses.
     c. They are produced by somatic mutations induced by carcinogenic
        substances.
     d. They are involved in producing proteins for cell adhesion.
     e. They are genes that code for proteins involved in cell division.

 21. What percentage of the DNA in the typical eukaryotic genome is
     expressed at any given time?
     a. 3-5%
     b. 5-20%
     c. 20-40%
     d. 40-60%
     e. 60-90%

22. In a nucleosome, what is the DNA wrapped around?
     a. polymerase molecules
     b. ribosomes
     c. mRNA
     d. histones
     e. nucleolus protein

 23. In eukaryotes, what is the active transcription generally associated
     with?
     a. euchromatin only
     b. heterochromatin only
     c. very tightly packed DNA only
     d. highly methylated DNA only
     e. both euchromatin and highly methylated DNA

 25. Muscle cells and nerve cells in one kind of animal owe their
     differences in structure to
     a. having different genes.
     b. having different chromosomes.
     c. using different genetic codes.
     d. expressing different genes.
     e. having unique ribosomes.

 26. Which of the following represents an order of increasingly higher
     levels of organization? 
     a. nucleosome, 30-nanometer chromatin fiber, looped domain
     b. looped domain, 30-nanometer chromatin fiber, nucleosome
     c. looped domain, nucleosome, 30-nanometer chromatin fiber
     d. nucleosome, looped domain, 30-nanometer chromatin fiber
     e. 30-nanometer chromatin fiber, nucleosome, looped domain

 27. A cell that remains flexible in its developmental possibilities is
     said to be
     a. differentiated.
     b. determined.
     c. totipotent.
     d. genomically equivalent.
     e. epigenic.

 28. The cloning of a plant from somatic cells is consistent with the
     view that
     a. differentiated cells retain all the genes of the zygote.
     b. genes are lost during differentiation.
     c. the differentiated state is normally very unstable.
     d. differentiated cells contain masked mRNA.
     e. cells can be easily reprogrammed to differentiate and develop
        into another kind of cell.

 29. What is meant by the word metastasis?
     a. the transformation of a normal cell to a cancer cell
     b. a mutation that causes cancer
     c. the spread of cancer cells from their site of origin
     d. the activation of an oncogene
     e. the development of contact inhibition

 31. A difference between prokaryote and eukaryote RNA is that
     a. prokaryote RNA has uracil, eukaryote RNA has thymine.
     b. eukaryote RNA lasts much longer before being degraded.
     c. prokaryote RNA never leaves the cell nucleus.
     d. prokaryote RNA contains deoxyribose.
     e. eukaryote RNA is in the form of a double helix.

 32. What do pseudogenes and introns have in common?
     a. They code for RNA end products, rather than proteins.
     b. They both contain uracil.
     c. They have multiple promoter sites.
     d. They both code for histones.
     e. They are not expressed nor do they code for functional proteins.

35. All of the following statements concerning the eukaryotic chromosome
     are true EXCEPT that
     a. it is composed of DNA and protein.
     b. the nucleosome is the structural subunit.
     c. gene expression is controlled by the histones.
     d. it consists of a single molecule of DNA wound around nucleosomes.
     e. active transcription occurs on euchromatin.

38. Most of the DNA in eukaryotic chromosomes is
     a. organized into operons.
     b. highly repetitive DNA.
     c. moderately repetitive DNA.
     d. single-copy DNA sequences that are never transcribed.
     e. single-copy sequences that are repeatedly transcribed.

52. When an advertiser wants to send out an ad, a computer prints an
     address label for everyone on a mailing list. This can be considered
     analogous to eukaryotic control of genes. The list might be
     considered to be the array of genes that need to be turned on. Using
     that analogy, the mailing labels would be analogous to
     a. methylated bases.
     b. transcription factors.
     c. enhancer regions.
     d. introns.
     e. RNA polymerase.

 53. If the structure of a TV show is analogous to the structure of a
     gene, then the introns of a gene would be analogous to
     a. the opening theme music.
     b. the segments of the show.
     c. the commercials between segments of the show.
     d. the commercials between shows.
     e. the closing credits.

 54. Which of the following is NOT a mechanism whereby a proto-oncogene
     is converted to an oncogene?
     a. methylation of bases
     b. point mutation
     c. gene transposition
     d. gene amplification
     e. chromosome translocation

Fill in the blank.

55.  A computer (hardware)is to a program (software) as a cell is to _______.
 

ANSWER KEY          MT