TLS Online TPP Program

#Question id: 7154


Cancer is believed to often arise from stem cells, rather than fully differentiated cells. Which of the following are consistent with this view?

#Unit 5. Developmental Biology
  1. Stem cells are actively dividing and express few differentiated functions, so they may have fewer changes to undergo than do fully differentiated cells in becoming cancer cells.
  2. DNA replication is necessary for mutations to occur, and stem cells are replicating their DNA whereas differentiated cells are for the most part not replicating their DNA.
  3. Teratocarcinomas are tumors that arise from germ cells or embryonic stem (ES) cells, under certain circumstances, demonstrating that tumors can arise from stem cells without further mutation.
  4. All of the above are reasons that cancer cells may more readily arise from stem cells than from fully differentiated cells.
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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?

TLS Online TPP Program

#Question id: 5301

#Unit 11. Evolution and Behavior

Which of the following processes is an early step in the whole-genome shotgun approach to sequencing?

TLS Online TPP Program

#Question id: 5302

#Unit 11. Evolution and Behavior

Using modern techniques of sequencing by synthesis and the shotgun approach, sequences are assembled into chromosomes by ________.