DNA as Genetic Material - Griffith, Avery, Hershey-Chase - Unsolved Practice Set
Chapter: Molecular Basis of Inheritance | Topic: DNA as Genetic Material Griffith Avery Hershey Chase
DNA AS GENETIC MATERIAL - GRIFFITH, AVERY, HERSHEY-CHASE - UNSOLVED PRACTICE SET
Topic: DNA as Genetic Material Griffith Avery Hershey Chase
Multiple Choice Questions
Q1. Griffith's transformation experiment was performed using two strains of:
- E. coli
- Streptococcus pneumoniae
- Bacteriophage
- Tobacco mosaic virus
Q2. In Griffith's experiment, mice injected with heat-killed S strain plus live R strain bacteria:
- Survived, with no bacteria found
- Died, and live S strain bacteria were recovered from them
- Died from R strain alone
- Showed no change at all
Q3. Avery, MacLeod, and McCarty confirmed that the "transforming principle" was DNA by showing that:
- Protease and RNase destroyed the transforming activity
- DNase (and not protease or RNase) destroyed the transforming activity
- Lipase destroyed the transforming activity
- No enzyme had any effect
Q4. In the Hershey-Chase experiment, bacteriophages were labelled with radioactive:
- Carbon and nitrogen
- Phosphorus (32P) and sulphur (35S)
- Oxygen and hydrogen
- Iodine only
Q5. The Hershey-Chase experiment concluded that the genetic material of the bacteriophage is:
- Protein
- DNA
- RNA
- Carbohydrate
Short Answer Questions
Q6. What was the "transforming principle" that Griffith discovered, even though he could not chemically identify it?
Q7. How did Avery, MacLeod, and McCarty experimentally prove that DNA, and not protein, is the transforming principle?
Q8. Why did Hershey and Chase use radioactive phosphorus and sulphur separately to label their bacteriophages?
Q9. What did the blender and centrifugation steps achieve in the Hershey-Chase experiment?
Long Answer Questions
Q10. Describe Griffith's transformation experiment in detail, explaining each of the four sets of mice used and the conclusions drawn from the results.
Q11. Explain the Hershey-Chase experiment, describing how it conclusively proved that DNA (and not protein) is the genetic material of bacteriophages.
APPLICATION / ANALYSIS
Q12. In a repeat of the Hershey-Chase experiment, if the radioactivity from 35S-labelled phages was found mainly in the pellet (inside bacterial cells) instead of the supernatant, what conclusion would this incorrectly suggest, and why would this contradict the actual DNA-based result?
Q13. A microbiology student is given heat-killed virulent bacteria and live non-virulent bacteria separately, and neither alone kills the test mice. Explain, based on Griffith's experiment, what result you would expect when both are injected together, and why.