Microbiology HW Ch.8 – Flashcards
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DNA strand complementary to CGA ATC AGC:
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GCT TAG TCG
DNA forms complementary strands by base pairing A with T and C with G.
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Correct statement concerning transcription:
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All types of RNA in the cell are synthesized by transcription, which uses a portion of DNA as a template for copying.Transcription is the process whereby RNA (all types of RNA) is synthesized from a DNA template.
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The flow of information in cells:
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mRNA is made by copying specific regions of DNA called genes. Ribosomes use mRNA as instructions, which provide a code specifying the order of amino acids in a protein.
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True statements concerning sugar utilization in E. coli:
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Bacteria growing on glucose as the sole carbon source grow faster than on lactose. E. coli utilizes glucose more efficiently as an energy source than lactose; therefore, E. coli grows faster in glucose than in lactose.
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Which of the following is a method of vertical gene transmission?
- cell division
- conjugation
- transformation
- transduction
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Cell division.Vertical transmission refers to transmission from parent to offspring, which occurs during cell division.
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Frederick Griffith did experiments on genetic transformation...
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Griffith found that DNA released from dead (virulent) bacteria entered live (avirulent) bacteria and changed them genetically, causing them to become virulent. This result indicated that the live bacteria obtained genetic information (DNA) from the dead bacteria. In this case, the new genes provide directions for synthesis of the capsule, which allows the live bacteria to become virulent.
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the Ames test
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-The test can be used to qualitatively test potential mutagens.
- The Ames test measures the reversion of histidine auxotrophs of Salmonella.
- The test uses bacteria as mutagen carcinogen indicators.
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What are the products of semiconservative replication for a double-stranded DNA molecule?
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Two double-stranded DNA molecules, each consisting of one parental strand and one daughter strand.
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Why is DNA replication essential for a cell?
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An organism must copy its DNA to pass genetic information to its offspring
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What is the function of the parental DNA in replication?
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It serves as the template for DNA replication.
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Transcription produces
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mRNA, tRNA, and rRNA
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Ribosomes contain
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rRNA
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involved in bringing amino acids to the ribosomes?
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tRNA
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mRNA
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Can be translated into protein
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What results from the process of translation?
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A polypeptide
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How is bacterial translation different from eukaryotic translation?
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Bacteria can begin translation before transcription has terminated.
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ribosomes move along the mRNA in which direction
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5' to 3'
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The structural genes
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transcribed into a single mRNA
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Which operons are always transcribed unless deactivated?
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Repressible operons
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Which operons are never transcribed unless activated?
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Inducible operons
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where on the DNA strand does a repressor bind?
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The operator
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sugar utilization in E. coli
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Bacteria growing on glucose as the sole carbon source grow faster than on lactose. E. coli utilizes glucose more efficiently as an energy source than lactose; therefore, E. coli grows faster in glucose than in lactose.
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A recombinant cell
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Is a cell that receives DNA from an outside source and incorporates it into its own.
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What is the hallmark of all horizontal gene transfers?
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Transfer of DNA between organisms of the same generation
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Which of the following is an example of horizontal gene transfer in bacteria?
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Transduction, conjugation, and transformation
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Bacterial conjugation is often referred to as bacterial sex. Why is this term inaccurate?
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Conjugation does not result in the formation of new offspring
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What must occur for bacterial conjugation to take place?
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The cells must come into contact with each other
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Competent cells are cells that
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can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination.
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Mice that are injected with only the R strain of Streptococcus pneumoniae
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stay healthy, because their immune systems can kill this strain easily.
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What characteristic of the S strain allows it to evade the immune system of the mice?
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The cells have a capsule.
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Which finding is most surprising from Griffith's experiments?
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S strain cells are isolated from the blood of mice infected with heat-killed S strains and live R strains.
