TLS Online TPP Program

#Question id: 1201


Epinephrine binds to the same type of receptors in liver, fat, and smooth muscle cells. Yet in liver, glycogen breaks down; in fat, triacylglycerols break down; and smooth muscle cells relax. How can the same hormone produce three such different responses?

#Unit 4. Cell Communication and Cell Signaling
  1. The same receptors activate three different second messengers.

  2. The same second messengers activate three different intracellular cascades.

  3. The same enzyme that breaks down glycogen also breaks down fat and relaxes muscle.

  4. None of the above.

More Questions
TLS Online TPP Program

#Question id: 3609

#Unit 8. Inheritance Biology

In humans, the dominance relationship between the A and B alleles of the ABO blood group gene is an example of

TLS Online TPP Program

#Question id: 1385

#Unit 4. Cell Communication and Cell Signaling

The ability of a population of fibroblasts to migrate along the surface of a tissue culture dish depends on adhesion between the cell surface and the extracellular matrix molecules coating the dish. The dish is coated with laminin, and the only cell-surface protein capable of binding laminin is a cell-adhesion protein called an integrin. Integrins are integral plasma-membrane proteins that function as heterodimers. Under these conditions the rate at which a fibroblast can migrate along the laminin coated culture dish is proportional to the strength of adhesion between the cell and the laminin substrate. The table below lists the rate of cell migration observed for fibroblasts genetically engineered to generate the indicated phenotypes.

 Which of the following is the most likely explanation for failure of overexpression of the integrin alpha subunit to alter the rate of fibroblast migration?

TLS Online TPP Program

#Question id: 2431

#Unit 2. Cellular Organization

Examples of actin cross-linking proteins include

a. fimbrin.        b. dystrophin.  c. α-actinin.     d. spectrin.      e. myosin S1.

TLS Online TPP Program

#Question id: 11553

#Unit 7. System Physiology – Animal

Tadpoles must undergo a major metamorphosis to become frogs. This change includes reabsorption of the tail, growth of limbs, calcification of the skeleton, increase in rhodopsin in the eye, development of lungs, change in hemoglobin structure, and reformation of the gut from the long gut of an herbivore to the short gut of a carnivore. Amazingly, all of these changes are induced by thyroxine. What is the most likely explanation for such a wide array of effects of thyroxine?

TLS Online TPP Program

#Question id: 1610

#Unit 4. Cell Communication and Cell Signaling

A polymorphonuclear neutrophil (PMN):