12.
Explain what happens to microfilaments within cells treated with cytochalasin D and why existing actin polymers eventually depolymerize. Fill in the blanks in the explanation below using words from the selections below.
Cytochalsin D _______ of monomers at ______ of existing filaments. When the concentration of G-actin in the cytosol is _______ the critical concentration, the loss of monomers at __________ of existing filaments eventually results in their shortening.
** Selections: prevents addition; equal to; plus ends; facilitates loss; above; below; both minus and plus ends; minus ends
18.
What effect does VX, a typical but potent acetylcholinesterase inhibitor, have on muscle function? Fill in the blanks in the explanation below. A word bank of choices follows.
Because the removal of acetylcholine is inhibited, the muscle membrane at the nueromuscular junction will remain _____ for an abnormally long period, causing the muscles to remain in a ______ state. The prolonged ______ in turn would be propagated via the T tubule system to ________ . The result would be prolonged release of calcium, resulting in sarcomere _______ via the effects of calcium on ________.
***Selections: polarized; depolarized; polarization; depolarization; shortening; relaxing; contracted; the sarcoplasmic reticulum; the troponin system; myosin; Z lines
12.
Explain what happens to microfilaments within cells treated with cytochalasin D and why existing actin polymers eventually depolymerize. Fill in the blanks in the explanation below using words from the selections below.
Cytochalsin D _______ of monomers at ______ of existing filaments. When the concentration of G-actin in the cytosol is _______ the critical concentration, the loss of monomers at __________ of existing filaments eventually results in their shortening.
** Selections: prevents addition; equal to; plus ends; facilitates loss; above; below; both minus and plus ends; minus ends
18.
What effect does VX, a typical but potent acetylcholinesterase inhibitor, have on muscle function? Fill in the blanks in the explanation below. A word bank of choices follows.
Because the removal of acetylcholine is inhibited, the muscle membrane at the nueromuscular junction will remain _____ for an abnormally long period, causing the muscles to remain in a ______ state. The prolonged ______ in turn would be propagated via the T tubule system to ________ . The result would be prolonged release of calcium, resulting in sarcomere _______ via the effects of calcium on ________.
***Selections: polarized; depolarized; polarization; depolarization; shortening; relaxing; contracted; the sarcoplasmic reticulum; the troponin system; myosin; Z lines
