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: 4534

#Unit 3. Fundamental Processes

The yeast Saccharomyces cerevisiae divides by budding: instead of dividing to produce two identical daughter cells, the so-called mother cell buds to produce a daughter cell, The HO gene is expressed only in mother cells and only at a certain point in the cell cycle,

#Question id: 4535

#Unit 3. Fundamental Processes

The activators bind—and the enhanceosome forms—in a highly cooperative manner, ensuring that all three activators must be present. The following are three ways the regulators might be binding cooperatively:

I- Through direct protein–protein interactions between them

II- By changes in the DNA caused by binding of one protein helping binding of another;

III- By the fact that the activators all interact simultaneously with the coactivator.

#Question id: 4536

#Unit 3. Fundamental Processes

The human b-interferon gene is activated in cells upon viral infection through some activators, EXCEPT one

#Question id: 4537

#Unit 3. Fundamental Processes

The enhancer DNA is __, but once the activators are bound it is relatively  , HMGA1 the DNA and thus helps the final structure form.

#Question id: 4538

#Unit 3. Fundamental Processes

We first consider a generic case. Gene A is controlled by four signals (1, 2, 3, and 4), each working through a separate activator (activators 1, 2, 3, and 4). Gene B is controlled by three signals (3, 5, and 6), working through activators 3, 5, and 6. It shows-

#Question id: 4539

#Unit 3. Fundamental Processes

The yeast S. cerevisiae exists in three forms: two haploid cells of different mating types—a and alpha and the diploid formed when an a and an a cell mate and fuse. The a cell and the a cell each encodes cell-type-specific regulators: a cells make the regulatory protein a1, and alpha cells make the proteins alpha1 and alpha2. A fourth regulatory protein, called Mcm1, is also involved in regulating the mating-type-specific genes (and many other genes) and is present in both cell types which shows Combinatorial Control.

The arrangement of regulators at the promoters of a-specific genes and a-specific genes is