What is the function of troponin
a. binds to calcium c. binds to heavy meromyosin
b. binds to tropomyosin d. binds with myosin binding site on actin
Adherens junctions:
a. are intermediate fiber based d. allow cytoplasmic continuity btw cells
b. only found in invertebrate cells e. are only found in embryonic tissues
c. form attachments with extracellular-matrix via integrins
Which type of filament forms the basis of desmosome junctions?
a. collagen c. intermediate fibers
b. actin filaments d. microtubules
Embryonic liver cells are gently dispersed with enzymes and combined with similarly dispersed retinal cells. When these cells are mixed and placed in fresh incubation media, they will:
a. quickly die, due to loss of intercellular junctions
b. slowly swell & lyse due to open gap junctions
c. reassemble into an amorphous (without order) tissue mass
d. form aggregates of liver and retinal cells
In fission yeast, the activity of MPF is regulated by phosphorylation and dephosphorylation. Which of the following protein enzymes inhibits the activity of the kinase?
a. MO15 c. Cdc25
b. Wee1 d. cyclin
Early cell cultures required the addition of blood plasma for growth. It was later determined the plasma accelerated growth of these cultures primarily because it contained:
a. start kinase d. ATP
b. mitotic kinase e. growth factors
c. calcium
M-phase promoting factor(MPF):
a. formed by G1 cyclin + Cdk c. required for beginning S spase of cell cycle
b. activated by phosphorylation d. conc. constant during cell cycle.
In contrast to cardiac muscle, smooth muscle:
a. is striated d. contraction requires calcium binding to troponin
b. contains the regulatory e. has a more intricate sarcoplasmic reticular
protein-tropomyosin network
c. myosin light chain kinase is inactive in resting state.
The start kinase requires the Cdc2 gene product (Cdk) plus:
a. mitotic cyclin c. G2 cyclin
b. G1 cyclin d. none of the above
The cellulose containing vesicles forming the cell plate of higher plants are formed from:
a. residual polar microtubules b. residual astral microtubules
c. fragmented endosplasmic reticulum
d. fragmented Golgi apparatus
e. secretory vesicles