The following statements regarding to the pancreas and its function.

a. The pancreas is composed of two major types of tissues, (1) the acini, which secrete digestive juices into the duodenum, and (2) the islets of Langerhans, which secrete insulin and glucagon directly into the blood.

b. The islets contain three major types of cells, alpha, beta, and delta cells

c. The beta cells, constituting about 25 percent of all the cells of the islets, lie mainly in the middle of each islet and secrete insulin and amylin.

d. The alpha cells, about 60 percent of the total, secrete glucagon and the delta cells, about 10 percent of the total, secrete somatostatin.

#Question id: 1253

#Unit 4. Cell Communication and Cell Signaling

Following statements are regarding to the wnt signalling.

A. Wnt proteins interact with several cell-surface proteins and activate multiple downstream signal transduction pathways. The principal signaling receptor for Wnt proteins is Frizzled (Fz), which contains seven transmembrane α helices.

B. The palmitate attached to the Wnt protein binds to a specific site on the Fz intracellular domain and stabilizes the Wnt-Fz complex.

C. “canonical” Wnt signaling pathway uses a second transmembrane protein, LRP, that associates with Frizzled in a Wnt signal– dependent manner.

D. In the resting state, two kinases in the complex, casein kinase 1 (CK1) and GSK3, sequentially phosphorylate β-catenin on multiple tyrosine residues.

Which of the following statements are correct?

#Question id: 10266

#Unit 8. Inheritance Biology

Self-pollination is the transfer of pollen from the anther of a flower to the stigma:

#Question id: 9616

#Unit 9. Diversity of Life Forms

Which mutation should least require realignment of homologous regions of a gene that is common to several related species?

#Question id: 3498

#Unit 11. Evolution and Behavior

Assuming 5 offspring of each female, A Female lion with a well-nourished cub gains inclusive fitness by nursing a starving cub of a full sister by 5% loss to herself. What would be value of be benefit in percent (all offspring of recipient female die in case of no nursing)

#Question id: 5207

#Unit 11. Evolution and Behavior

Why is it unwise to try to relate an organismʹs complexity with its size or number of cells?