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1.1 Genome Size & Complexity — Test 1
Q1. Denaturation–renaturation kinetics of genomic DNA generates a Cot curve. Which statement is INCORRECT for the Cot curve/value?✓ It is identical in all organisms
Q2. Density-gradient centrifugation of an organism's genomic DNA shows a lower-density 'satellite' peak in addition to the main peak. This is most likely due to:✓ AT-rich satellite DNA
Q3. Genome size refers to the total amount of DNA contained in a:✓ Haploid genome
Q4. Highly repetitive DNA sequences in a eukaryotic chromosome are normally concentrated near the:✓ Centromeric (heterochromatic) region
Q5. Pyrosequencing (a sequencing-by-synthesis method) is especially useful for:✓ Sequencing short DNA regions in many individuals
Q6. Which statement is NOT true for satellite DNA?✓ It renatures very slowly
Q7. In a Cot curve, a DNA sample that reassociates at the LOWEST Cot½ value is:✓ The most highly repetitive
Q8. The C-value paradox refers to the observation that:✓ Genome size (C-value) does not correlate with organismal complexity
Q9. In a reassociation (Cot) experiment, the three kinetic classes of eukaryotic DNA in increasing Cot½ order are:✓ Highly repetitive < moderately repetitive < unique (single-copy)
Q10. Cot½ (the Cot value at which half the DNA has reassociated) is directly proportional to:✓ The sequence complexity of the DNA
Q11. Renaturation (reassociation) of denatured DNA follows which order of kinetics with respect to DNA concentration?✓ Second order
Q12. Repetitive DNA that occurs as a small number of related copies dispersed through the genome (e.g. rRNA gene families) is best termed:✓ Moderately (middle) repetitive DNA
Q13. The kinetic complexity of a genome measured by Cot analysis corresponds to:✓ The total length of non-repeated (unique) sequence
Q14. Which organism is expected to have the LOWEST Cot½ for the bulk of its genome (fastest reassociation)?✓ A eukaryote rich in satellite DNA
Q15. Reannealing of DNA in a Cot experiment is typically carried out at a temperature about:✓ 20–25°C below the Tm
Q16. Genome size is commonly expressed in picograms of DNA per haploid nucleus; this is known as the:✓ C-value
Q17. Which of the following contributes MOST to the large genome sizes of many eukaryotes (the C-value paradox)?✓ Abundant repetitive and non-coding DNA
Q18. In CsCl density-gradient centrifugation, the main band of genomic DNA represents the bulk DNA, while minor satellite bands differ because they have a distinct:✓ Base composition (GC content)
Q19. Which best describes 'single-copy' (unique) DNA in a eukaryotic genome?✓ Sequences present once or a few times, including most protein-coding genes
Q20. In a Cot curve, the x-axis (Cot, on a log scale) represents:✓ DNA concentration × time of reassociation