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TLS Online TPP Program

#Question id: 18928

With respect to nucleic acid hybridization, which, if any, of the following statements is false?

#Unit 13. Methods in Biology
  1. The probe is a labeled nucleic acid or oligonucleotide that is expected to hybridize to a target DNA sequence within an unlabelled test nucleic acid population.
  2. The probe is a known single-stranded nucleic acid or oligonucleotide that is intended to hybridize to complementary target sequences in a poorly understood nucleic acid test sample.
  3. The object of a hybridization assay is to identify target sequences within a test sample that are related to the probe so that some new information is gained about the target sequences.
  4. During a hybridization assay, a heteroduplex is formed by un-natural base pairing between complementary probe and target sequences that show a sufficiently high degree of base pairing across part or all of their lengths.
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TLS Online TPP Program

#Question id: 5295

#Unit 8. Inheritance Biology

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: 5296

#Unit 8. Inheritance Biology

A transformation experiment is performed with a donor strain that is resistant to four drugs: A, B, C, and D. The recipient is sensitive to all four drugs. The treated recipient cell population is divided up and plated on media containing various combinations of the drugs. The table below shows the results. What is the probable order of the three tightly linked genes?  
TLS Online TPP Program

#Question id: 5297

#Unit 8. Inheritance Biology

In a generalized transduction experiment, phages are collected from an E. coli donor strain of genotype cys+ leu+thr+ and used to transduce a recipient of genotype cys_ leu_ thr_. Initially, the treated recipient population is plated on a minimal medium supplemented with leucine and threonine. Many colonies are obtained. These colonies are then replica-plated onto three different media: What is order of gene?
TLS Online TPP Program

#Question id: 5298

#Unit 8. Inheritance Biology

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: 5299

#Unit 8. Inheritance Biology

One particular group of mutant strains specifically required the amino acid arginine to grow, and these arginine auxotrophs formed the basis of their subsequent analysis, given in table 
TLS Online TPP Program

#Question id: 5300

#Unit 11. Evolution and Behavior

What is metagenomics?