S2 Unit 1 Atomic Structure and Periodic Table / 5 of 16 Your teacher gives you a sample of an unknown element which is sealed in a glass tube at room temperature. At the bottom of the tube
there is a small amount, a few drops at the most, of a red-black filmy liquid, and above it is a red vapor. What is this element likely to be?
(DOK 1)
O A. non-metal
Exhi
O
B. metal
O
C. metalloid
INTL
12:34
Lenovo

Choose the incorrect statement (a) the motor end plate membrane is only capable of generating graded potentials, but it is contiguous with the skeletal muscle sarcolemma, which can generate action potentials. (b) propagation of an action potential through the t-tubules into the sarcoplasmic reticulum triggers the release of ca++ into the cytoplasm of a skeletal muscle fiber. (c) the generation of suprathreshold endplate potentials in multiple muscle fibers could be due to the increased frequency of action potential generation at the axon hillock of a single motor neuron. (d) a greater amount of ach would be found in the presynaptic vesicles of a motor unit that fired several action potentials after exposure to botulinum toxin, than in a motor unit that fired several action potentials after exposure to the venom of the krait snake (which contains α-bungarotoxin).