D and E are points on the sides AB and AC respectively of DABC such that DE is parallel to BC and AD : DB = 4 : 5, CD and BE intersect each other at F. Then find the ratio of the areas of DDEF and DCBF.

#Question id: 11550

#Unit 7. System Physiology – Animal

Which of the following are similar in structure to cholesterol?

I) estradiol

II) insulin

III) glucocorticoids

IV) testosterone

V) antidiuretic hormone

#Question id: 11551

#Unit 7. System Physiology – Animal

Polypeptides can have which of the following types of effects?

I) autocrine

II) paracrine

III) endocrine

#Question id: 11552

#Unit 7. System Physiology – Animal

Which of the following are properties of steroid hormones?

I) Steroid hormones are lipid soluble and easily cross the phospholipid bilayer.

II) Steroid hormones usually exert their effects on target cells through membrane receptor proteins.

III) Steroid hormones act on cells close to where they were produced.

IV) Steroid hormones regulate gene transcription by binding to intracellular receptor proteins.

#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?

#Question id: 11554

#Unit 7. System Physiology – Animal

What happens in a cell when adenylyl cyclase is activated?

#Question id: 11555

#Unit 7. System Physiology – Animal

Nitric oxide and epinephrine ________.