Bio Ch 39

Description:	Plant Response to Internal and External Signals
Category:	Biology
Created by:	kccroy on 2009-03-18

Question	Answer
The step(s) between a plant's perception of a change in the environment and the plant's response to that change is (are) best called..	signal transduction
Which of the following statement is (are) true of plants?	Plants adjust their growth and development in response to environmental cues.
External stimuli would be received most quickly by a plant cell if the receptors for signal transduction were located in the...	cell membrane.
Secondary messengers are associated with which of the following?	transduction
In a signal transduction pathway, the transduction stage amplifies the original signal by...	Having each receptor molecule produce multiple secondary messengers and having each secondary messenger activate numerous specific enzymes.
What would happen if the secondary messenger cGMP was blocked in the de-etiolation pathway?	Ca 2+ channels could open, and specific protein kinase 2 could still be produced
If protein synthesis was blocked in eitiolated cells, what would be necessary for any de-etiolation to occur?	post-translational modification of existing proteins
Charles and Francis Darwin concluded from their experiments on photropism by grass seedlings that the part of the seedling that detects the direction of light is the...	tip of the coleoptile.
Pants growing in a partially dark environment will grow toward light in a response called phototropism. Choose the incorrect statement regarding phototropism:	Auxin causes a decrease in growth on the side of the stem exposed to light.
Which of these conclusions is supported by the research of both Went and Charles and Frances Darwin on shoot responses to light?	A chemical substance involved in shoot bending is produced in shoot tips.
We know from the experiments of the past that plants bend toward light because	cell expansion is greater on the dark side of the stem.
Plant hormones can be characterized by all of the following except that they:	function independently of other hormones
Why is it so difficult to study the actions of plant hormones?	All of the above make the study of plant hormones difficult.
Plant hormones can have different effects at different concentrations. This explains how ...	auxin can stimulate cell elongation in apical meristems, yet will inhibit the growth of axillary buds.
Which plant hormones might be used to enhance stem elongation and fruit growth?	auxins and gibberellins.
According to the acid growth hypothesis, auxin works by..	increasing wall plasticity and allowing the affected cell wall to elongate.
Which of the following hormones would be most useful in promoting the rooting of plant cuttings?	auxins
Which plant hormone(s) is (are) most closely associated with cell division?	cytokinin
One effect of gibberellins is to stimulate cereal seeds to produce ...	amylase
In attempting to make a seed break dormancy, one logically could treat it with..	gibberellins.
Both and red and blue light are involved in...	stem elongation.
Most plants close their stomata at night. What color of light would be most effective in promoting stomatal opening in the middle of the night?	blue
The biological clock controlling circadian rhythms must ultimately ...	affect gene transcription.
Plants often use changes in day length (photoperiod) to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes:	are more predictable than air temperature changes.
Plants often use changes in day length (photoperiod) to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes:	are more predictable than air temperatures.
A botanist exposed two groups of the same plant species to two photoperiods-one with 14 hours of light and 10 hours of dark and the other with 10 hours of light and 14 hours of dark. Under the first set of conditions, the plants flowered, why?	The plants flower in the spring.
In order to flower, a short-day plant needs a..	night that is longer than certain length.
A long-day plant is if..	the duration of continuous darkness is less than a critical length
Plants that have their flowering inhibited by being exposed to bright lights at night are:	short-day plants.
If you take a short-day plant and put it in a lab under conditions where it will flower (long nights and short days), but interrupt its day period with a few minutes of darkness, what will happen?	It will flower.
Florigen is a flowering signal, not yet chemically identified, found in:	leaves.
What do results of research on gravitropic responses of roots and stems show?	The effect of a plant hormone can depend on the tissue.
If you wanted to genetically engineer a plant to be more resistant to drought, increasing amounts of which of the following hormones might be a good first attempt?	abscisic acid
The initial response of the root cells of a tomato plant watered with seawater would be to..	begin to plasmolyze as water is lost.
Plants are affected by an array of pathogens. Which of the following is not a plant defense against disease?	All of the above are plant defenses against disease.
The breakdown of chlorophyll reveals the ________ pigments of a leaf...	carotenoid
The protective layer that forms between the abscission layer and the stem consists of ...	weak, colorless, thin-walled cells.
After leaf abscission, growth will resume from the..	petiole
What is the specific term that refers to seasonal changes in the relative lengths of night and day?	photoperiod
Day-neutral plants flower regardless of...	day length, night length, or photoperiod.
Which hormone is incorrectly paired with its function?	cytokinins—initiate programmed cell death
Buds and sprouts often form on tree stumps. Which of the following hormones would you expect to stimulate their formation?	cytokinins
How might a plant respond to severe heat stress?	By producing heat-shock proteins, which may protect the plants proteins from denaturing.