Question

36. glucagon is secreted from pancreatic alpha cells into the blood stream. it can specifically bind to a cell surface receptor and modulate cellular activituues of various cell types. glucagon stumulation in humans

a. result in an increase in glycogen synthesis

b. leads ri activation of protein kinase C

c. leads to an increase in blood glucose level

d. is best classified as paracrine signal

34. which stage if mitosis starts as sister chromatids split apart and begin to move towards opposite poles?

a. anaphase

b. prometaphase

c. metaphase

d. prophase

e. telophase

Answer 1

Ans:

36.

C. leads to an increase in blood glucose level.

Explanation: Glucagon is a hormone secreted by pancreatic alpha cells. If glucose concentration of cell is low, Pancreatic cells releases glucagon which coverted glycogen to glocse. Glucagon stumulation increases blood glucose level by activation of hepatic glycogenolysis and gluconeogenesis. Glucagon stimulates the breakdown of glycogen by activating glycogen phosphorylase enzyme. Glycogen synthesis is increased by insulin hormone. Protein kinase A is activated by glucagon stumulation. Protein kinase C is activated by Ca2+, DAG, and phospholipid. The signal molecules released by a cell affects only neibouring target cells is called paracrine signalling.

34.

a. Anaphase

Explanation: In anaphase of mitosis, the two sister chromatids separated and moved towards the opposite pole of the cell. The centromere divide longitudinally and spindle fibers pull the chromatids to the opposite pole. At metaphase, all the shorest and thickest chromosomes lie on the equatorial plane and the spindle fibers are attached to the kinetochore of centromere. In telophase, the separated chromosomes arrive in the pole and the nuclear membrane re-appear in this stage. The chromosomes uncoil in this stage so they become very long and thin. In prometaphase stage, the chromosomes become increasingly shorter and thicker due to increased condensation. In prophase, chromosomes appear as thread-like structure.