Lederberg and Tatum Used the Bacterial Strains Bio^-met^-leu⁺thr⁺thi⁺and Bio⁺met⁺leu^-thr^-thi^-in Their

question 82

Multiple Choice

Lederberg and Tatum used the bacterial strains bio^-met^-leu⁺thr⁺thi⁺and bio⁺met⁺leu^-thr^-thi^-in their experiments to determine if genetic recombination occurs in bacteria. Would it have been better to use two strains with the genotypes met^-leu⁺and met⁺leu^-instead?

• A) Yes, because it is easier to study two genes than five genes.
• B) Yes, because the met^-leu⁺and met⁺leu^-strains only have one mutation, which makes it easier for genetic recombination to occur.
• C) No, because the met^-leu⁺and met⁺leu^-strains only have one mutation. A single random mutation could restore methionine or leucine synthesis in the strains.
• D) No, because strains with only one nutrient-deficient gene can still grow on minimal medium.
• E) No, because cells have two genes that encode different versions of leucine, so the met⁺leu^-strain would still be able to grow on minimal medium.

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Definitions:

Spike

A sharp increase or sudden upward movement, as in the context of graphs, prices, or signals.

Strong and Broad

Typically refers to the characteristic appearance of certain signals in spectroscopy, indicating a large distribution of energy levels or interactions.

IR Absorption

The process where a molecule absorbs infrared radiation, leading to vibrational transitions, used in spectroscopy to identify chemical compounds.

Intense IR Absorption

Refers to the strong absorption of infrared light by a molecule, typically due to specific bond vibrations, useful in identifying functional groups.