Question

1.)When plants bend toward the light in response to auxin, the signal response includes…

(a) only an intracellular response

(b) only an intercellular response

(c) both an intracellular and an intercellular response

(d) magic

2.)The production of auxin is mediated by which wavelength of light?

(a) blue

(b) green

(c) red

(d) far-red

3.)Many plants are categorized as “short day” or “long day” plants. The environmental factor that determines the time of year when these plants flower is

(a) a critical light period

(b) a critical dark period

(c) a critical concentration of constitutive compounds

(d) the concentration of abscisic acid in the roots

4.)A plant scientist was hired by a greenhouse operator to devise a way to force iris plants to bloom in the short days of winter. Iris normally blooms as long-day (short-night) plants. Which of the following has the best chance of creating iris blooms in winter?

(a) Interrupt the long winter nights with a brief period of light.

(b) Increase the temperature to more closely follow summer temperatures.

(c) Artificially increase the period of darkness in the greenhouse.

(d) Grow the plant in 24 hours of light each day.

5.)You have a small tree in your yard that is the height that you want it but does not have as many branches as you want. How can you prune/trim it to cause an increase in the number of axillary/lateral branches and why?

(a) Cut off all of the lower branches; transpiration will increase to the apical leaves.

(b) Cut off the tips of the main shoots; cytokinin production will decrease causing the axillary/lateral buds to begin growing.

(c) Cut off the leaves at the ends of several axillary/lateral branches; absicic acid will become more prevalent.

(d) Cut off the tips of the roots; cytokinin production will decrease and auxin will promote growth of the axillary/lateral branches

(e) Cut off the tips of the main shoots; auxin production will decrease causing the axillary/lateral buds to begin growing.

6.)Which of the following statements best summarizes the acid-growth hypothesis in an actively growing shoot?

(a) Auxins and gibberellins together act as a lubricant to help stretch cellulose microfibrils.

(b) Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and makes the walls more flexible.

(c) Auxin stimulates proton pumps in the plasma membrane and tonoplast.

(d) Auxins activate aquaporins that increase turgor pressure in the cells.

Answer 1

Answer 1) option c) both inter and intra cellular response are present. This involves transportation of phots to plasma membrane as tetra cellular response and transportation of auxin to target cells is inter cellular response.
Answer 2) option a) blue light also known as UV light will mediate the production of auxin in plants.

Answer 3) option b) a critical dark period. This is because the phenomenon of short day plants and long day plants is given the amount of photoperiod In which the plant measures the length of the nights and not day.

Answer 4) option c) by artificially increasing the period of darkness in the greenhouse will help iris plant to bloom as it will then measure the long nights and function accordingly.

Answer 5) option e) is correct. This is because when we cut off the tip of the main branch the apical meristem of the main branch is lost causing auxin to decrease hence stopping its growth while the auxin production will increase for the lateral branches.
Answer 6) option b) is correct because according to the acid growth hypothesis  Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and makes the walls more flexible.