Genetics Mutations Classification
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Questions and Answers

What theory states that living creatures could arise without parents?

  • Biological Molecules Theory
  • Spontaneous Generation Theory (correct)
  • Germ Theory
  • Abiogenesis Theory

    • Which of the following is NOT one of Koch’s Postulates used to describe the role of microbes in diseases?

  • The suspected organism should be present in ALL cases of the disease and ABSENT from healthy animals (correct)
  • Cells from a pure culture of the suspected organism should CAUSE DISEASE in a healthy animal
  • The suspected organism should be grown in PURE CULTURE
  • The suspected organism should be REISOLATED (the same organism as before)

    • What is the main function of 16S rRNA in bacterial evolution?

  • To determine genetic relatedness and serve as a molecular clock (correct)
  • To initiate spontaneous generation of new bacteria
  • To cause disease in healthy animals
  • To preserve food and destroy crops

    • How did the theory of spontaneous generation get disproved?

    <p>By introducing microorganisms from the outside into sterile liquid</p> Signup and view all the answers

    Which type of molecules arise abiotically from simply reduced chemicals sparked by lighting?

    <p>Organic building blocks</p> Signup and view all the answers

    What is the most widely used molecular clock for bacterial evolution?

    <p>$16S rRNA$</p> Signup and view all the answers

    What is the main impact of microorganisms on food availability?

    <p>It affects food availability both positively and negatively</p> Signup and view all the answers

    Which theory describes the idea that a specific type of microorganism causes a specific disease?

    <p>$Germ Theory$</p> Signup and view all the answers

    Which type of molecules contain temporal information used as a molecular clock?

    <p>$16S rRNA$</p> Signup and view all the answers

    What is the main reason behind the constant substitution rate in molecular clocks?

    <p>$16S rRNA$ has a slow evolving sequence divergence proportional to time</p> Signup and view all the answers

    Which type of mutation does not change the amino acid sequence?

    <p>Silent mutation</p> Signup and view all the answers

    What is the enzyme that promotes transposition in the simplest transposons?

    <p>Transposase</p> Signup and view all the answers

    What is the function of the Ames test?

    <p>To test the strength of mutagens</p> Signup and view all the answers

    Which repair mechanism corrects mismatches missed by proofreading?

    <p>Methyl mismatch repair</p> Signup and view all the answers

    What happens when extensive DNA damage induces SOS response?

    <p>RecA inactivates LexA</p> Signup and view all the answers

    What type of repair recognizes and repairs bases that mostly do not distort DNA structure?

    <p>Base-excision repair</p> Signup and view all the answers

    What is a characteristic of transversion mutations?

    <p>Change from purine to pyrimidine or vice versa</p> Signup and view all the answers

    What is the term used for the addition of one or more bases in DNA?

    <p>Insertion</p> Signup and view all the answers

    What is a characteristic of silent mutations?

    <p>Does not change the amino acid sequence</p> Signup and view all the answers

    What is a characteristic of point mutations?

    <p>Changes in a single base</p> Signup and view all the answers

    What distinguishes prokaryotic cells from eukaryotic cells in terms of DNA location?

    <p>Prokaryotic DNA is not bounded by a membrane</p> Signup and view all the answers

    Which bacterial cell shape is characterized by a helical structure?

    <p>Vibrios</p> Signup and view all the answers

    What is the main difference between the envelopes of Gram-positive and Gram-negative bacteria?

    <p>Gram-negative bacteria have an outer membrane</p> Signup and view all the answers

    What step of the Gram stain procedure removes the stain from Gram-negative but not from Gram-positive cells?

    <p>Wash with ethanol</p> Signup and view all the answers

    How can chemical gradients across membranes be used to drive cellular processes?

    <p>By storing energy in the gradient</p> Signup and view all the answers

    What is the primary characteristic of active transport?

    <p>Direct use of energy to move molecules against the gradient</p> Signup and view all the answers

    Which transport system combines active energy use with facilitated diffusion?

    <p>PTS transport</p> Signup and view all the answers

    What distinguishes Sec-dependent secretion systems in bacteria?

    <p>Requires ATP hydrolysis to move proteins out</p> Signup and view all the answers

    What type of transport system escorts specific substrate to transporter?

    <p>'ABC' transporters</p> Signup and view all the answers

    What happens to the signal peptide during the secretion via Sec-dependent secreted proteins?

    <p>The signal peptide is cleaved by the signal peptidase enzyme during secretion</p> Signup and view all the answers

    What is the main advantage of using ribosomal DNA for evolutionary studies?

    <p>It encodes components of the transcription and translation apparatus</p> Signup and view all the answers

    According to the endosymbiont theory, how did mitochondria and chloroplasts originate?

    <p>They were bacteria that were infected or eaten by other species and ended up living symbiotically inside</p> Signup and view all the answers

    What is the role of the restriction/modification system in bacterial cells?

    <p>To cut foreign DNA using restriction endonucleases and protect native DNA by methylation</p> Signup and view all the answers

    Which enzyme is responsible for removing RNA primers and filling the gaps in the lagging DNA strand during bacterial chromosomal replication?

    <p>DNA polymerase I</p> Signup and view all the answers

    What is the function of sigma factors in transcription?

    <p>They recognize promoters and guide the core enzyme to initiate transcription</p> Signup and view all the answers

    What is the general role of repressors in gene expression regulation?

    <p>They bind to regulatory sequences and prevent transcription of target genes</p> Signup and view all the answers

    What are open reading frames (ORFs) in the context of molecular genetics?

    <p>Triplets of nucleotides that represent amino acids in translation</p> Signup and view all the answers

    In Rho-independent transcriptional termination, what causes the RNA polymerase to pause and terminate transcription?

    <p>Formation of stem-loop structure due to GC-rich sequence</p> Signup and view all the answers

    How does prokaryotic translation differ from eukaryotic translation?

    <p>Prokaryotic translation uses different initiation and release factors compared to eukaryotic translation</p> Signup and view all the answers

    What is the significance of the Shine-Dalgarno sequence in translation?

    <p>It allows binding of mRNA to the ribosome's small subunit for translation initiation</p> Signup and view all the answers

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