TLS Online TPP Program

#Question id: 8922


Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships?

#XL - T Zoology
  1. increased incidence of worm burrows in the fossil record
  2. increased incidence of hard parts in the fossil record
  3. increased incidence of organic material in the fossil record
  4. increased incidence of fern galls in the fossil record
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TLS Online TPP Program

#Question id: 5287

#XL - S Microbiology

Interrupted matting of different Hfr strain with F- E.coli cell resulting generation of following strain  Order of gene is

TLS Online TPP Program

#Question id: 5290

#XL - S Microbiology

The following table shows mapping data from three interrupted mating experiments using three different Hfr strains and an F- strain: The order of genes is

TLS Online TPP Program

#Question id: 5295

#XL - S Microbiology

A cross is made between an Hfr that is met+ thi+ pur+ and an F-that is met- thi- pur-. Interrupted mating studies show that met+ enters the recipient last, so met+ recombinants are selected on a medium containing supplements that satisfy only the pur and thi requirements.  These recombinants are tested for the presence of the thi+ and pur+ alleles. The following numbers of individuals are found for each genotype:

A) Gene Order

I

Thi Pur  Met

II

Pur  Met  Thi

III

Pur   Thi  Met

B) Distance between Pur and Thi

IV

15.4 map unit

V

1.8 map unit

What is the following correct combination?

TLS Online TPP Program

#Question id: 5298

#XL - S Microbiology

Four E. coli strains of genotype a+ b− are labeled 1, 2, 3, and 4. Four strains of genotype a− b+ are labeled 5, 6, 7, and 8. The two genotypes are mixed in all possible combinations and (after incubation) are plated to determine the frequency of a+ b+ recombinants. The following results are obtained, where M = many recombinants, L = low numbers of recombinants, and 0 = no recombinants. On the basis of these results, assign a sex type (either Hfr, F+, or F−) to each strain

TLS Online TPP Program

#Question id: 5323

#XL - T Zoology

An X-linked recessive gene produces red-green color blindness in humans. A woman with normal color vision whose father was color-blind marries a color-blind man. What is the probability that their son will be color-blind?

TLS Online TPP Program

#Question id: 5324

#XL - T Zoology

In eusocial insects, males develop from unfertilized eggs while females develop from fertilized eggs. The ultimate consequence of this difference is that