TLS Online TPP Program

#Question id: 1020


HIV/AIDS can be categorized as a new or emerging infectious disease. By putting it into this category, we are effectively saying that

#Unit 4. Cell Communication and Cell Signaling
  1. this infection hasn't been observed in the human population prior to recent (approximately 50 years or sooner) outbreaks

  2. this disease has been in susceptible populations for centuries, but has only recently achieved infection levels that became detectable.

  3. the infectious agent is still evolving and changing, unlike with older, more established diseases such as plague or polio.

  4. the disease has always been in susceptible populations and causing disease, but we lacked the technology to detect it.

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TLS Online TPP Program

#Question id: 3632

#Unit 8. Inheritance Biology

geneticist is working with a new bacteriophage called phage Y3 that infects E. coli. He has isolated eight mutant phages that fail to produce plaques when grown on E. coli strain K. To determine whether these mutations occur at the same functional gene, he simultaneously infects E. coli K cells with paired combinations of the mutants and looks to see whether plaques are formed. He obtains the following results. (A plussign means that plaques were formed on E. coli K; a minussign means that no plaques were formed on E. coli K.)

How many cistron belong to these mutation?

TLS Online TPP Program

#Question id: 4661

#Unit 3. Fundamental Processes

In bacteria two components regulatory systems contain a domain can have function such as controlling the direction in which the bacterium swims in response to a concentration gradient of nutrients is known as

TLS Online TPP Program

#Question id: 11963

#Unit 7. System Physiology – Animal

Which of the following is generally true?

TLS Online TPP Program

#Question id: 11908

#Unit 8. Inheritance Biology

What is the phenotype of a person who has XXXY sex chromosomes?

TLS Online TPP Program

#Question id: 1370

#Unit 4. Cell Communication and Cell Signaling

H. V. Wilson worked with sponges to gain some insight into exactly what was responsible for holding adjacent cells together. He exposed two species of differently pigmented sponges to a chemical that disrupted intercellular junctions, and the cells of the sponges dissociated. Wilson then mixed the cells of the two species and removed the chemical that caused the cells to dissociate. Wilson found that the sponges reassembled into two separate species. The cells from one species did not interact or form associations with the cells of the other species.

How do you explain the results of Wilson's experiments?