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Ch. 39 - Plant Responses to Internal and External Signals

Chapter 39, Problem 7

A plant mutant that shows normal gravitropic bending but does not store starch in its plastids would require a reevaluation of the role of          in gravitropism. a. auxin b. calcium c. statoliths d. differential growth

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Welcome back. Let's look at our next question. All of the following are true statements regarding gravity trumpism except so remember we're looking for a false statement about gravity trumpism and we can recall from our content videos um trumpism is that phenomenon where a plant bends or changes the direction of its growth. In response to something in this case. Looking at the prefix gravity. So when a plant changes or parts of a plant change the direction of growth in response to gravity. So let's look through our answer choices, choice and remembering that we're looking for a false statement. Choice A says it is the response to gravity in plants. That is true, that's the definition of gravity prism. So choice A is not a correct answer. Choice B says status is an animal, a place that is involved in gravity trumpism and yes. Um A status is a specialized kind of antelope. Last those are cells that store starch and they're found in those gravity sensing cells in plants. Um These little starch Granules in there, so they are involved in gravity trumpism being present in those gravity sensing cells. With these little starch Granules. So that is a true statement and will eliminate choice B. Choice E says roots of plants show positive grava trumpism. That is true gravity, autism causes roots to grow downwards in the direction of gravity. So Choice C. Is not an answer and finally we have choice D. Which says plants cannot show grava trumpism if they do not store starch well because the presence of those static lifts in those gravity sensing cells. It was thought that plants that didn't store starch would not be able to show gravity is um However, there have been some mutants discovered that cannot store starch but still show gravity trumpism. So this is a false statement. We now know that um the ability to store starch is not necessary to show grava trumpism. So this is a false statement and therefore Choice D. Is our answer. So Choice D. For which statement is not true regarding grava trumpism. See you in the next video.