Following statements are regarding to the fluidity of a bilayer.

A. A lipid bilayer cools below a characteristic transition temperature, it undergoes a sort of phase change in which it becomes a liquid; that is, it loses its fluidity.

B. Above the transition temperature, the highly mobile lipids are in a state known as a liquid crystal.

C. The bilayer is thicker in the gel state than in the liquid crystal state due to the stiffening of the hydrocarbon tails at lower temperatures.

D. The transition temperature of a bilayer decreases with the chain length and the degree of saturation of its component fatty acid residues for the same reasons that the melting points of fatty acids increase with these quantities.

Which of the following combination is correct?

#Question id: 1397

#Unit 4. Cell Communication and Cell Signaling

The vertebrate equivalent of CED-9 is:

#Question id: 1398

#Unit 4. Cell Communication and Cell Signaling

Which of the following properties is (are) characteristic of a benign tumor?

a. well differentiated              b. localized to tissue of origin             c. metastatic               

d. promotes angiogenesis        e. surrounded by a fibrous capsule

#Question id: 1399

#Unit 4. Cell Communication and Cell Signaling

Loss-of-function mutations in which of the following genes typifies colorectal carcinomas?

a. myc              b. K-ras                       c. p53              d. APC

#Question id: 1400

#Unit 4. Cell Communication and Cell Signaling

Which property is shared by malignant tumor cells and transformed cells in culture?

a. reduced growth factor requirement                        b. attachment-dependent growth

c. loss of actin microfilaments                                    d. altered morphology

#Question id: 1402

#Unit 4. Cell Communication and Cell Signaling

Which of the following oncoproteins possess(es) protein kinase activity?

#Question id: 1403

#Unit 4. Cell Communication and Cell Signaling

Tumor-suppressor genes encode proteins with which of the following functions?

a. growth-promoting               b. growth-arresting                  c. pro-apoptotic

d. anti-apoptotic                      e. DNA repair