prototrophic HFR strain and an Streptomycin Resistant gly- tyr- ala- pro- ser- auxotrophic strain. The following results are obtained: Numbers of colonies of each Genotype over time Minutes before mating interrupted colony 10 20 30 40 50 60 60 TO 70 88 80 genotype gly+ 0 0 0 0 380 375 392 401 tyr+ 98 396 398 389 395 401 403 399 ala+ 0 0 O 0 0 200 398 406 prot 0 79 301 287 304 304 298 297 ser+ 0 140 300 301 298 287 289 301 1. Which gene is transferred from donor to recipient first? 2. a. gly b. tyr C. ala d. pro e. ser Which gene is transferred from donor to recipient last? a. gly b. tyr C. ala d. pro e. ser 3. Which of the following is true? a. Gly is closer to ala than pro is to ser b. The StrpR colony type Tyr+ Pro+ Ser- would be expected to be the least abundant if the gene order was tyr pro ser C The StrpR colony type Tyr+ Pro+ Ser- would be expected to be the least abundant if the gene order was tyr ser pro d. The StrpR colony type Tyr+ Pro+ Ser- would be expected to be the least abundant if the gen order was pro tyr ser

Type S Streptococcus pneumoniae bacterium is lethal and will kill its host. If heat inactivated the S strain dies and becomes nonlethal. Type R Streptococcus pneumoniae is a nonvirulent strain of bacteria. What would occur if one were to inject both the R strain and heat-killed S strains into a host organism such as the mouse? The R strain would be transformed into the virulent S strain and kill the host. Neither the S nor the R strain would change. The R strain would be transformed into the virulent S strain and not affect the host. The S strain would be transformed into the nonvirulent R strain and not affect the host The S strain would be transformed into the nonvirulent R strain and kill the host.

Molecular detail of D614G strain of SARS CoV-2

How did Griffith determine which strain caused disease?