Most biology textbooks prior to 1990 listed the major function of ribonucleic acid (RNA) as transferring information from DNA to make
proteins. In late 1989, Thomas Cech proposed that RNA had a second major
function: as a catalyst for chemical reactions that occur inside the cell. His
discovery surprised most scientists and caused the rewriting of many
chapters in biology textbooks. What aspect of the scientific process does
this best illustrate?

Where in the cell are ribosomes made?

Dan made the table shown to describe two different relationships between animals. organism interactions relationship a relationship b one organism lives inside the organism it feeds off no organism is harmed which of the following statements is most likely correct?

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).