TLS Online TPP Program

#Question id: 2919


Topoisomerases play the essential role of unlinking the DNA molecules to allow them to separate into the two daughter cells for cell division. Which of the following statements regarding the mechanism of topoisomerases is INCORRECT?

#Unit 2. Cellular Organization
  1. Melting of the DNA strands is favored in highly negatively supercoiled DNA making this DNA an excellent substrate for relaxation.

  2. This product DNA is identical to the starting DNA molecule, except that the linking number has been increased by 1.

  3. Topoisomerase function requires that DNA cleavage, strand passage, and DNA rejoining all occur in a highly coordinated manner.

  4. The OH group from one broken DNA end attacks the phospho-tyrosine bond re-forming the DNA phosphodiester bond via ATP hydrolysis.

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TLS Online TPP Program

#Question id: 11647

#Unit 7. System Physiology – Animal

After menopause, hormone replacement therapy with estrogen-like compounds is effective in preventing the progression of osteoporosis. What is the mechanism of their protective effect?

TLS Online TPP Program

#Question id: 11648

#Unit 7. System Physiology – Animal

Within minutes following a normal delivery, flow through the foramen ovale decreases dramatically. What is the cause of this change?

TLS Online TPP Program

#Question id: 11649

#Unit 7. System Physiology – Animal

The red lines in the figure above illustrate the normal relationships between plasma insulin concentration and glucose production in the liver and between plasma insulin concentration and glucose uptake in muscle


In the figure, which lines most likely illustrate these relationships in a patient with type 2 diabetes?

TLS Online TPP Program

#Question id: 11650

#Unit 7. System Physiology – Animal

The red lines in the figure above illustrate the normal relationships between plasma insulin concentration and glucose production in the liver and between plasma insulin concentration and glucose uptake in muscle.


 

In the figure, which lines most likely illustrate these relationships in a patient with acromegaly?

TLS Online TPP Program

#Question id: 11681

#Unit 7. System Physiology – Animal

A baby is born with a penis, a scrotum with no testes, no vagina, and XX chromosomes. This condition is referred to as hermaphroditism. Which of the following could cause this abnormality?

TLS Online TPP Program

#Question id: 11682

#Unit 7. System Physiology – Animal

A young woman is given daily injections of a substance beginning on the 16th day of her normal menstrual cycle and continuing for 3 weeks. As long as the injections continue, she does not menstruate. The injected substance could be which of the following?