Mastering Bio Ch 36 And 39

Which tissue acts as a filter on the water absorbed by root hairs? a) Epidermis b) Vascular tissue c) Endodermis d) Cortex

True or false? Root pressure can move water a long distance up the xylem because of the higher water potential of the xylem in comparison to the water potential in the surrounding cells. a) True b) False

Which of the following statements about the distribution of sap throughout a plant is true? a) The driving force for sugar movement is transpiration. b) The mechanism that explains the movement of sugars throughout a plant is called the pressure-flow hypothesis. c) Companion cells form the conducting tissue for sap. d) The main component of phloem sap is glucose.

Which term describes an area where sugars are used or stored? a) Leaves b) Stomata c) Sink d) Source

Which of the following statements about xylem transport is true? a) Water and minerals move through the root cortex into the xylem and upward through the stem and into leaves. b) The xylem cells that conduct water and minerals are alive. c) Water and minerals enter the xylem by diffusion. d) All water transported by the xylem is used for photosynthesis in the leaves.

What characterizes the rates of photosynthesis and transport in a plant on a dry cloudy day? a) Both the photosynthesis and transpiration rates are high. b) The photosynthesis rate is low and stomata are open. c) The photosynthesis rate is high and phloem transport rates are low. d) Both the photosynthesis and transpiration rates are low.

True or false? The rate of sugar transport in a plant depends on the rate of photosynthesis, the rate of transpiration, and the difference in turgor pressure between the source and the sink. a) True b) False

Plants must always compromise between _____ and _____. See Concept 36.1 (Page 783) a) maximizing water loss ... minimizing H+ protons b) maximizing photosynthesis ... minimizing water loss c) maximizing access to light ... minimizing intake of CO2 d) maximizing transport of minerals ... minimizing transport of sugars e) maximizing water absorption ... minimizing leaf area

A plant cell placed in a solution with a lower (more negative) water potential will _____. 36.2 (Page 786) a) gain water and plasmolyze b) gain water and become turgid c) lose water and plasmolyze d) lose water and become turgid e) lose water and burst

Which of the following is a correct statement about a difference between xylem and phloem transport? See Concept 36.3 (Page 790) a) Active transport moves xylem sap but not phloem sap. b) Phloem carries water and minerals; xylem carries organic molecules. c) Xylem sap moves up; phloem sap moves up or down. d) Xylem sap moves from sugar source to sink, but phloem sap does not. e) Transpiration moves phloem sap but not xylem sap.

A student is performing a chemical analysis of xylem sap. This student should not expect to find much _____. See Concept 36.3 (Page 790) a) phosphorus b) sugar c) nitrogen d) potassium e) water

Which one of the following refers to the loss of water through the stomata in a plant's leaves? 36.4 (Page 795) a) guttation b) bulk flow c) transpiration d) respiration e) osmosis

In addition to transporting sugar, the phloem also _____. See Concept 36.6 (Page 800) a) transmits electrical signals b) transports viral RNA throughout the plant c) transports plant RNA throughout the plant d) transports proteins throughout the plant e) All of the above

Movement of phloem sap from a source to a sink a) depends ultimately on the activity of proton pumps. b) results mainly from diffusion. c) depends on tension, or negative pressure potential. d) depends on pumping water into sieve tubes at the source. e) occurs through the apoplast of sieve-tube elements.

Photosynthesis ceases when leaves wilt, mainly because a) photolysis, the water-splitting step of photosynthesis, cannot occur when there is a water deficiency. b) the chlorophyll in wilting leaves is degraded. c) stomata close, preventing CO2 from entering the leaf. d) flaccid mesophyll cells are incapable of photosynthesis. e) accumulation of CO2 in the leaf inhibits enzymes.

Which of the following would tend to increase transpiration? a) higher stomatal density b) a rainstorm c) sunken stomata d) spiny leaves e) a thicker cuticle

Select the accurate statement about water potential. a) Free water moves from a region of lower water potential to a region of higher water potential. b) Water in a turgid cell has positive pressure potential. c) Adding solutes to water increases water potential.

Select the correct mechanism of stomatal opening and closing. a) Light stimulates proton pumps in the plasma membrane of the guard cells, causing them to lose K+ and become flaccid. b) The radial orientation of cellulose microfibrils in the cell walls of guard cells causes them to bow outward and open the stomatal pore when turgid. c) The cell walls of guard cells are thickened on the side of the stomatal opening and the thinner walls bow outward when the guard cells become turgid, to close the stomata.

If a plant's stomata are closed and no transpiration is occurring, which of the following predictions is accurate? a) Without transpiration, the plant will be water deficient. b) Without transpiration, less water will be absorbed from the soil. c) Without transpiration, the plant's cells will become flaccid.

Plant hormones act by directly affecting the activities of _____. See Concept 39.1 (Page 842) a) genes and enzymes b) membranes c) genes d) enzymes e) signal transduction pathways

Which of the following seedlings will probably bend toward light? See Concept 39.2 (Page 854) a) one whose tip is separated from its base by a gelatin block b) one whose tip is covered with a black plastic cap c) one whose tip is cut off d) one whose tip is separated from its base by aluminum foil e) one whose tip is cut off and topped by a gelatin block containing no plant substances

Which of these plant hormones is not typically considered a growth-promoting substance? 39.2 (Page 845) a) cytokinin b) brassinosteroids c) abscisic acid d) auxin e) gibberellin

The Pr form of the phytochrome pigment has maximum absorption in the _____ part of the spectrum. 39.3 (Page 854) a) blue b) red c) yellow d) ultraviolet e) far-red

Most plants flower when _____. 39.3 (Page 857) a) a certain number of days have passed since they last flowered b) the soil reaches a certain temperature c) the days are the right length d) the nights are the right length e) they deplete soil nutrients

What is the physical basis of the phototropic response? a) Cell shortening. b) Photosynthesis. c) Cell transport. d) Cell elongation.

True or false? Auxin is asymmetrically distributed in shoots because the auxin on the side of the plant facing the source of light is destroyed. a) True b) False

Where does the majority of stem growth in a plant occur? a) Axillary buds. b) Lateral branches. c) Both the apical meristem and lateral branches. d) Apical meristem.

Which of the following statements about hormones is true? a) Hormones are small inorganic molecules. b) Hormones can function at very low concentrations. c) Hormones are produced at the sites where they are needed. d) Hormones are produced only in plants.

Which term describes the direction of auxin transport in a plant? a) Circular. b) Multidirectional. c) Bidirectional. d) Polar.

How does auxin produce gravitropism in a plant that is placed on its side? a) Auxin accumulates on the side of the leaf opposite the sunlight and stimulates elongation of cells in that region. b) Auxin accumulates on the lower surface of the root and stimulates elongation of cells in that region. c) Auxin accumulates on the side of the leaf opposite the sunlight and inhibits elongation of cells in that region. d) Auxin accumulates on the lower surface of the root and inhibits elongation of cells in that region.

How does auxin produce phototropism? a) Auxin accumulates in cells on the side of the plant facing the source of light and causes them to shorten. b) Auxin accumulates in cells on the side of the plant opposite the source of light and causes them to shorten. c) Auxin accumulates in cells on the side of the plant opposite the source of light and stimulates their elongation. d) Auxin accumulates in cells on the side of the plant facing the source of light and stimulates their elongation.

If a long-day plant has a critical night length of 9 hours, which 24-hour cycle would prevent flowering? a) 14 hours light/10 hours dark b) 16 hours light/8 hours dark c) 8 hours light/8 hours dark/light flash/8 hours dark d) 15.5 hours light/8.5 hours dark e) 4 hours light/8 hours dark/4 hours light/8 hours dark