Which of the following statements does not accurately describe the events involved in the propagation of an action potential?
(a) An initial influx of Na+ through a small cluster of channels causes local depolarization of the membrane.
(b) Local depolarization causes nearby Na+ channels to open.
(c) Channels in depolarized regions of the membrane are inactivated until the resting membrane potential is reestablished.
(d) The opening of transmitter-gated K+ channels helps to repolarize the membrane.
(d) The outflow of K+ through voltage-gated K+ channels helps bring the membrane back to its resting potential.
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You are asked to determine if a tissue sample taken from a plant stem comes from a monocot or eudicot. How will you accomplish this?
A. Look at the ground tissue to see if it is arranged in concentric rings or in parallel bundles. B. Examine the vascular cambium and determine if it is divided into segments or is continuous throughout the stem. C. Determine if the xylem and phloem are located in separate vascular bundles or are bundled together. D. Examine the epidermis and determine the depth of the cuticle layer. E. Locate the vascular bundles and analyze their pattern.
If integration of DNA provided by pronuclear injection occurs after three cell divisions, the resulting mouse will
A) not contain the transgene in any cells. B) be a mosaic of cells with some cells containing the transgene and others not. C) contain the transgene in only germ cells. D) contain the transgene in only somatic cells.
A ________ can contain DNA or RNA as its genetic material, but not both.
Fill in the blank(s) with the appropriate word(s).
A teenager shows up at a clinic with lesions on his face. The sores are raised, light-colored bumps with a waxy texture. A few similar lesions are present on the torso as well. With which of the following viruses might he be infected?
A) human herpesvirus 1 B) B19 virus C) human herpesvirus 4 D) molluscum contagiosum E) papillomavirus