Ryan-physh.docx

Name:_____________________________ Yr:____ Final Exam In Plant Physiology (2019) I. Choose the letter of the BEST answer.Write the letter in the space before the number. 1.) Which of the following statements is false concerning the xylem? A) Xylem tracheids and vessels fulfill their vital function only after their death. B) The cell walls of the tracheids are greatly strengthened with cellulose fibrils forming thickened rings or spirals. C) Water molecules are transpired from the cells of the leaves, and replaced by water molecules in the xylem pulled up from the roots due to the cohesion of water molecules. D) Movement of materials is by mass flow; solutes in xylary sap move due to a positive turgor pressure gradient from source to sink. E) In the morning, sap in the xylem begins to move first in the twigs of the upper portion of the tree, and later in the lower trunk. 2) Water rises in plants primarily by cohesiontension. Which of the following is not true about the cohesion-tension model? A) Water loss (transpiration) is the driving force for water movement. B) The "tension" of this model represents the excitability of the xylem cells. C) Cohesion represents the tendency for water molecules to stick together by hydrogen bonds. D) The physical forces in the capillary-sized xylem cells make it easier to overcome gravity. E) The water potential of the air is more negative than the xylem. 3) Assume that a particular chemical interferes with the establishment and maintenance of proton gradients across the membranes of plant cells. All of the following processes would be directly affected by this chemical except A) photosynthesis. B) phloem loading. C) xylem transport. D) cellular respiration. E) stomatal opening. 4) Which cells in a root form a protective barrier to the vascular system where all materials must move through the symplast? A) pericycle B) cortex C) epidermis D) endodermis E) exodermis 5) Guard cells do which of the following? A) protect the endodermis B) accumulate K+ and close the stomata

C) contain chloroplasts that import K+ directly into the cells D) guard against mineral loss through the stomata E) help balance the photosynthesis-transpiration compromise 6) All of the following normally enter the plant through the roots except A) carbon dioxide. B) nitrogen. C) potassium. D) water. E) calcium. 7) Photosynthesis begins to decline when leaves wilt because A) chloroplasts within wilted leaves are incapable of photosynthesis. B) CO2 accumulates in the leaves and inhibits the enzymes needed for photosynthesis. C) there is insufficient water for photolysis during the light reactions. D) stomata close, restricting CO2 entry into the leaf. E) wilted leaves cannot absorb the red and blue wavelengths of light. 8) The water lost during transpiration is a side effect of the plant's exchange of gases. However, the plant derives some benefit from this water loss in the form of A) evaporative cooling. B) mineral transport. C) increased turgor. D) increased growth, E) only evaporative cooling and mineral transport. 9) Ignoring all other factors, what kind of day would result in the fastest delivery of water and minerals to the leaves of a tree? A) cool, dry day B) warm, dry day C) warm, humid day D) cool, humid day E) very hot, dry, windy day 10) If the guard cells and surrounding epidermal cells in a plant are deficient in potassium ions, all of the following would occur except A) photosynthesis would decrease. B) roots would take up less water. C) phloem transport rates would decrease. D) leaf temperatures would decrease. E) stomata would be closed. 11) The opening of stomata is thought to involve A) an increase in the solute concentration of the guard cells. B) a decrease in the solute concentration of the stoma. C) active transport of water out of the guard cells.

D) decreased turgor pressure in guard cells. E) movement of K+ from the guard cells. 12) All of the following are adaptations that help reduce water loss from a plant except A) transpiration. B) sunken stomata. C) C4 photosynthesis. D) small, thick leaves. E) crassulacean acid metabolism. 13) A primary result for stomatal closure on a hot, dry day would be A) release of K+ ions to the apoplast and subsidiary cells. B) displacement of Ca++ ions from the thick inner walls of the guard cells. C) disassembly of the microfibrils in the cell walls of the subsidiary cells. D) upregulation of aquaporin synthesis. E) downregulation of extension proteins. 14) What is the driving force for the movement of solutes in the phloem of plants? A) gravity B) a difference in water potential (Ψ) between the source and the sink C) root pressure D) transpiration of water through the stomata E) adhesion of water to phloem sieve tubes 15) According to the pressure flow hypothesis of phloem transport, A) solute moves from a high concentration in the source to a lower concentration in the sink. B) water is actively transported into the source region of the phloem to create the turgor pressure needed. C) the combination of a high turgor pressure in the source and transpiration water loss from the sink moves solutes through phloem conduits. D) the formation of starch from sugar in the sink increases the osmotic concentration. E) the pressure in the phloem of a root is normally greater than the pressure in the phloem of a leaf.

C) a thicker cuticle D) higher stomatal density E) spiny leaves 18) If you wanted to increase the cation exchange and water retention capacity of loamy soil, what should you do? A) adjust the soil pH to 7.9 B) add clay to the soil C) practice no-till agriculture D) add fertilizer containing potassium, calcium, and magnesium to the soil E) increase the number of sand particles in the soil 19) Most of the water taken up by a plant is A) used as a solvent. B) used as a hydrogen source in photosynthesis. C) lost during transpiration. D) converted to CO2. E) used to keep cells turgid. 20) A soil well suited for the growth of most plants would have all of the following properties except A) abundant humus. B) air spaces. C) good drainage. D) high cation exchange capacity. E) a high pH. 21) Why does overwatering a plant kill it? A) Water does not have all the necessary minerals a plant needs to grow. B) Water neutralizes the pH of the soil. C) The roots are deprived of oxygen. D) Water supports the growth of root parasites. E) Water lowers the water potential of the roots. 22) Which of the following soil minerals is most likely leached away during a hard rain? A) Na+ B) K+ C) Ca++ + D) NO3 E) H

16) What is the main cause of guttation in plants? A) root pressure B) transpiration C) pressure flow in phloem D) plant injury E) condensation of atmospheric water

23) The NPK percentages on a package of fertilizer refer to the A) total protein content of the three major ingredients of the fertilizer. B) percentages of manure collected from different types of animals. C) relative percentages of organic and inorganic nutrients in the fertilizer. D) percentages of three important mineral nutrients. E) proportions of three different nitrogen sources.

17) Which of the following would tend to increase transpiration? A) a rainstorm B) sunken stomata

24) A young farmer purchases some land in a relatively arid area and is interested in earning a reasonable profit for many years. Which of the following strategies would best allow the farmer to

achieve such a goal? A) establishing an extensive irrigation system B) using plenty of the best fertilizers C) finding a way to sell all parts of crop plants D) selecting crops adapted to arid areas E) converting hillsides into fields 25) Which of the following would be the most effective strategy to remove toxic heavy metals from a soil? A) heavy irrigation to leach out the heavy metals B) application of fertilizers to compete with heavy metal uptake C) application of sulfur to lower the soil pH and precipitate the heavy metals D) adding plant species that have the ability to take up and volatilize heavy metals E) inoculating soil with mycorrhizae to avoid heavy metal uptake 26) Most of the dry weight of a plant is derived from A) NO3 and CO2. C) PO4 and K. B) K and CO2. D) H2O and K. E) H2O and CO2. 27) A growing plant exhibits chlorosis of the leaves, especially the older, more mature ones. The chlorosis is probably due to a deficiency of which of the following macronutrients? A) carbon B) oxygen C) nitrogen D) calcium E) hydrogen 28) Which of the following elements is incorrectly paired with its function in a plant? A) nitrogen component of nucleic acids, proteins, hormones, coenzymes B) magnesium component of chlorophyll; activates many enzymes C) phosphorus component of nucleic acids, phospholipids, ATP, several coenzymes D) potassium cofactor functional in protein synthesis, osmosis, operation of stomata E) sulfur component of DNA; activates some enzymes 29) Which of the following elements, if increased in concentration, would increase the stability of cell walls? A) zinc B) chlorine C) calcium D) molybdenum E) manganese 30) What is a major function of magnesium in plants? A) to be a component of lignin-biosynthetic enzymes B) to be a component of DNA and RNA

C) to be a component of chlorophyll D) to be active in amino acid formation E) to be required to regenerate phosphoenolpyruvate in C4 and CAM plants 31) Reddish-purple coloring of leaves, especially along the margins of young leaves, is a typical symptom of deficiency of which element? A) C C) N ++ B) M D) P E) K+ 32) Which of the following best describes the general role of micronutrients in plants? A) They are cofactors in enzymatic reactions. B) They are necessary for essential regulatory functions. C) They prevent chlorosis. D) They are components of nucleic acids. E) They are necessary for the formation of cell walls. 33) Which of the following is not true of micronutrients in plants? A) They are elements required in relatively small amounts. B) They are required for a plant to grow from a seed and complete its life cycle. C) They generally help in catalytic functions in the plant. D) They are the essential elements of small size and molecular weight. E) Deficiencies vary widely by soil type. 34) A plant seedling bends toward sunlight because A) auxin migrates to the lower part of the stem due to gravity. B) there is more auxin on the light side of the stem. C) auxin is destroyed more quickly on the dark side of the stem. D) auxin is found in greatest abundance on the dark side of the stem. E) gibberellins produced at the stem tip cause phototropism. 35) The apical bud of a shoot produces ________, resulting in the inhibition of lateral bud growth. A) abscisic acid B) ethylene C) cytokinin D) gibberellin E) auxin 36) The ripening of fruit and the dropping of leaves and fruit are principally controlled by A) auxins. B) cytokinins. C) indole acetic acid. D) ethylene. E) carbon dioxide concentration (in air).

37) Which plant hormones would likely be found in high amounts in a sprouting vegetative stem? A) auxins, gibberellins, cytokinins B) gibberellins, brassinosteroids, cytokinins C) auxins, abscisic acid, ethylene D) auxins, phytochrome, brassinosteroids E) gibberellins, cytokinins, abscisic acid 38) Which of the following plant hormones would be found in very low amounts in a mature, waterstressed tomato plant? A) auxins, abscisic acid, B) auxins, gibberellins, cytokinins C) gibberellins, cytokinins, ethylene D) cytokinins, abscisic acid E) ethylene, auxin 39) When growing plants in culture, IAA is used to stimulate cell enlargement. Which plant growth regulator has to now be added to stimulate cell division? A) ethylene B) indoleacetic acid C) gibberellin D) cytokinin E) abscisic acid 40) Why do coleoptiles grow toward light? A) Auxin is destroyed by light. B) Gibberellins are destroyed by light. C) Auxin synthesis is stimulated in the dark. D) Auxin moves away from the light to the shady side. E) Gibberellins move away from the light to the shady side. 41) Which of the following statements applies to plant growth regulators? A) They only act by altering gene expression. B) They often have a multiplicity of effects. C) They function independently of other hormones. D) They directly control plant protein synthesis and assembly. E) They affect the division and elongation, but not the differentiation, of cells. 42) Plant hormones produce their effects by A) altering the expression of genes. B) modifying the permeability of the plasma membrane. C) modifying the structure of the nuclear envelope membrane. D) altering the expression of genes and modifying the permeability of the plasma membrane. E) modifying the permeability of the plasma membrane and modifying the structure of the nuclear envelope membrane. 43) Which of the following hormones would never be found in high concentrations in a dormant overwintering flower bud?

A) auxin B) cytokinins C) abscisic acid D) ethylene

E) gibberellins

44) Auxins (IAA) in plants are known to affect all of the following phenomena except A) geotropism of shoots. B) maintenance of dormancy. C) phototropism of shoots. D) inhibition of lateral buds. E) fruit development. 45) Which of the following plant hormones are most likely to act synergistically if expressed or applied to a drought-stricken plant? A) auxin and ethylene B) phytochrome and gibberellins C) gibberellins and abscisic acid D) abscisic acid and ethylene E) ethylne and cytokinins 46) Which of the following hormones would be most useful in promoting the rooting of plant cuttings? A) oligosaccharins B) abscisic acid C) cytokinins D) gibberellins E) auxins 47) Which of the following plant hormones would most likely be found in high concentrations in a mature, slightly overripe fruit? A) auxins and cytokinins B) auxins and abscisic acid C) gibberellins and cytokinins D) cytokinins and ethylene E) abscisic acid and ethylene 48) If you were shipping green bananas to a supermarket thousands of miles away, which of the following chemicals would you want to eliminate from the plants' environment? A) CO2 B) cytokinins C) ethylene D) auxin E) gibberellic acids 49) Which of the following plant growth responses is primarily due to the action of auxins? A) leaf abscission B) fruit development C) cell division D) the detection of photoperiod E) cell elongation 50) A short-day plant will flower only when A) days are shorter than nights. B) days are shorter than a certain critical value. C) nights are shorter than a certain critical value. D) nights are longer than a certain critical value. E) days and nights are of equal length.