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Unformatted text preview: ronds are initiated after the plant has been inverted, they will grow upward, even if the frond from which they are growing is oriented downward (Figure III). 156. Which of the following conclusions is best indicated by the additional experiment in Figure III ? (A) Cellular gravity sensors are likely not responsible for the establishment of polarity. (B) Tip growth always occurs perpendicular to the pull of gravity. (C) Newly formed cytoplasm is fully differentiated and cannot respond to altered orientation. (D) The change in polarity is expressed only in newly formed cytoplasm. (E) Coenocytic organisms do not display cellular differentiation.
Unauthorized copying or reuse of any part of this page is illegal. 157. Which of the following procedures would best test whether the induction of polarity is regulated at the transcriptional level? (A) Expose plants to a protein synthesis inhibitor, then invert. (B) Invert plants, then expose to a protein synthesis inhibitor. (C) Expose plants to an RNA synthesis inhibitor, then invert. (D) Invert plants, then expose to an RNA synthesis inhibitor. (E) Expose plants to a DNA synthesis inhibitor, then invert. GO ON TO THE NEXT PAGE. 44 Questions 158-159 The average daily temperature change on an exposed south-facing slope and a north-facing slope for a late summer day in the Northern Hemisphere are shown below. 158. Compared with a south-facing slope, the climatic conditions on a north-facing slope favor the formation of a vegetation community best adapted to (A) colder temperatures and wetter environments (B) colder temperatures and drier environments (C) hotter temperatures and similar moisture environments (D) hotter temperatures and wetter environments (E) hotter temperatures and drier environments 159. The difference in the maximum average daily temperature between the south-facing slope and the north-facing slope is approximately (A) (B) (C) (D) (E) 0° C 5° C 10°C 25°C 35°C GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 45 Questions 160-163 In experiments to determine possible metabolic side effects of a new industrial by-product X941, the rate of respiratory oxygen consumption by isolated mitochondria was assayed. The mitochondria were maintained in a solution containing high concentrations of dissolved oxygen and inorganic phosphate. Figure 1 shows the results of a control experiment. Pyruvic acid, the principal metabolic precursor for the citric acid cycle, was added to isolated mitochondria, followed a short time later by the addition of ADP. Figure 2 illustrates the effect of adding X941 instead of ADP. 160. Which of the following best explains why O2 concentration does not decrease until after the addition of ADP, as shown in Figure 1 ? (A) The proton gradient that drives electron transport can be produced only by phosphorylation of ADP. (B) A complete turn of the citric acid cycle requires several ADP’s directly. (C) ADP is a substrate, along with pyruvate, for pyruva...
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This document was uploaded on 03/16/2014 for the course BIO 1434 at UT Arlington.
- Spring '14