Bio Exam #2 – Flashcards

) Which of the following is correctly paired with its structure and function? A) sclerenchyma supporting cells with thick secondary walls B) ground meristem protective coat of woody stems and roots C) guard cells waterproof ring of cells surrounding the central stele in roots D) periderm parenchyma cells functioning in photosynthesis in leaves

A student examining leaf cross sections under a microscope finds many loosely packed cells with relatively thin cell walls. The cells have numerous chloroplasts. What type of cells are they? A) parenchyma B) xylem C) endodermis D) collenchyma E) sclerenchyma

Which of the following describes secondary growth? A) growth in height B) development of leaves and flowers C) growth of herbaceous tissue D) development of wood and bark E) development of fruit

While walking a cornfield, you notice roots emerging from the corn stalks themselves, and you suspect that these roots are helping to hold the plants upright. These roots belong to a category of roots known as A) Taproots B) Fibrous roots C) Adventitious roots D) Root hairs E) Special roots

________ is to xylem as ________ is to phloem. A) Sclerenchyma cell; collenchyma cell B) Apical meristem; vascular cambium C) Vessel element; sieve-tube member D) Cortex; pith E) Vascular cambium; cork cambium

When you eat Brussels sprouts, you are eating _____. A) immature flowers B) large axillary buds C) petioles D) storage leaves E) storage roots

Loss of water from the aerial parts of plants is called _____. A) dehydration B) high heat of vaporization C) respiration D) gas exchange E) transpiration

The veins of leaves are _____. I) composed of xylem and phloem II) continuous with vascular bundles in the stem and roots III) finely branched to be in close contact with photosynthesizing cells A) only I B) only II C) only III D) I and III E) I, II, and III

) Compared to plants from other environments, the cells of many desert plants contain high concentrations of solutes. This helps them survive in their arid surroundings because the high solute concentrations create relatively _____, which help reduce water loss. A) low solute potentials B) high pressure potentials C) low pressure potentials D) high solute potentials

Root hairs are most important to a plant because they _____. A) anchor a plant in the soil B) store starches C) increase the surface area for absorption D) provide a habitat for nitrogen-fixing bacteria E) contain xylem tissue

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

What drives the flow of water through the xylem? A) passive transport by the endodermis B) the number of companion cells in the phloem C) the evaporation of water from the leaves D) active transport by sieve-tube elements E) active transport by tracheid and vessel elements

Water potential (ψ) can be thought of as the tendency for water to move from one place to another. In plants, it is made up mainly of solute potential and pressure potential. Hypothetical plant cells A and B are adjacent to each other. The solute potential (ψS) of cell A is -0.35 MPa, and its pressure potential (ψP) is +0.15 MPa. The solute potential (ψS) of cell B is -0.30 MPa, and its pressure potential (ψP) is +0.05 MPa. In which direction will net water movement occur? A) Neither; cells A and B are in equilibrium with each other. B) from cell A to cell B C) from cell B to cell A

) In hydroponic culture, what is the purpose of bubbling air into the solute? A) to keep dissolved nutrients evenly distributed B) to provide oxygen to the root cells C) to inhibit the growth of aerobic algae D) to inhibit the growth of anaerobic bacteria E) to provide carbon dioxide for photosynthesis

Active transport involves _____. A) diffusion of solute through the lipid bilayer of a membrane B) pumping of solutes across the membrane C) production of adenosine triphosphate (ATP) D) transport of solute down a concentration gradient

) 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

Mycorrhizae enhance plant nutrition mainly by _____. A) absorbing water and minerals through the fungal hyphae B) providing sugar to root cells, which have no chloroplasts C) converting atmospheric nitrogen to ammonia D) enabling the roots to parasitize neighboring plants E) stimulating the development of root hairs

) A mineral deficiency is likely to affect older leaves more than younger leaves if the _____. A) mineral is a micronutrient B) mineral is very mobile within the plant C) mineral is required for chlorophyll synthesis D) mineral is a macronutrient E) older leaves are in direct sunlight

19) What is a typical habitat for carnivorous plants? A) wet areas with high salinity B) wet areas with high levels of humus C) wet areas with low decomposition rates D) dry areas with low levels of available oxygen E) dry areas with high levels of peat

20) Nitrogen fixation is a process that _____. A) recycles nitrogen compounds from dead and decaying materials B) converts ammonia to ammonium C) releases nitrate from the rock substrate D) converts nitrogen gas into ammonia E) recycles nitrogen compounds from dead and decaying materials, and converts ammonia to ammonium

21) What is the function of proton pumps localized in the plant plasma membrane? A) to facilitate diffusion of ions B) to transfer phosphorus groups from ATP to proteins C) to transfer metal ions across the plasma membrane D) to transfer anions across the plasma membrane E) to create a membrane potential

Clay in soils represents a trade-off in nutrient availability, such that _____. A) anions are less likely to leach out of soil and are difficult for plants to extract B) cations are less likely to leach out of soil and are difficult for plants to extract C) nitrogen levels are exceptionally high, but much of the nitrogen leaches away D) oxygen levels are exceptionally high, but much of the nitrogen leaches away

) What is the correct sequence of steps during infection of plants by nitrogen-fixing bacteria? A) Rhizobia release Nod factors; roots release flavonoids; rhizobia proliferate inside of root hair; infection thread grows into the root cortex; nodule forms. B) Rhizobia release flavonoids; roots release Nod factors; rhizobia proliferate inside of root hair; infection thread grows into the root cortex; nodule forms. C) Roots release flavonoids; rhizobia release Nod factors; rhizobia proliferate inside of root hair; nodule forms; infection thread grows into the root cortex. D) Roots release flavonoids; rhizobia release Nod factors; rhizobia proliferate inside of root hair; infection thread grows into the root cortex; nodule forms. E) Nodule forms; infection thread grows into the root cortex; rhizobia proliferate inside of root hair; rhizobia release flavonoids and Nod factors.

You are conducting an experiment on plant growth. You take a plant fresh from the soil that weighs 5 kilograms (kg). Then you dry the plant overnight and determine the dry weight to be 1 kg. Of this dry weight, how much would you expect to be made up of organic molecules?

) What do the results of research on gravitropic responses of roots and stems show? A) Different tissues have the same response to auxin. B) The effect of a plant hormone can depend on the tissue. C) Some responses of plants require no hormones at all. D) Light is required for the gravitropic response. E) Cytokinin can only function in the presence of auxin.

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 _____. A) are more predictable than air temperature changes B) predict moisture availability C) are modified by soil temperature changes D) can reset the biological clock

) Plant hormones _____. A) in plant cells naturally exist in very large amounts B) change their shape in response to stimulus C) are unable to move from one cell to another D) affect only cells with the appropriate receptor

) Which of the following is the most likely plant response to an attack by herbivores? A) leaf abscission to prevent further loss of tissue B) early flowering to reproduce before being eaten C) production of chemical compounds for defense or to attract predators D) production of physical defenses, such as thorns E) production of thicker bark and cuticle to make it more difficult to eat

) According to the acid-growth hypothesis, auxin works by _____. A) dissolving sieve plates, permitting more rapid transport of nutrients B) dissolving the cell membranes temporarily, permitting cells that were on the verge of dividing to divide more rapidly C) changing the pH within the cell, permitting the electron transport chain to operate more efficiently D) increasing wall plasticity and allowing the affected cell walls to elongate E) greatly increasing the rate of deposition of cell wall material

) Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the _____. A) tip of the coleoptile B) part of the coleoptile that bends during the response C) base of the coleoptile D) cotyledon E) phytochrome in the leaves

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

Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only 1 4 -inch of soil is that the _____. A) seedlings do not produce a hypocotyl B) seedlings do not have an etiolation response C) seeds require light to germinate D) seeds require a higher temperature to germinate E) seeds are very sensitive to waterlogging

) 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) carbon dioxide B) cytokinins C) ethylene D) auxin E) gibberellic acids

Which of the following sex and generation combinations directly produces the pollen tube of angiosperms? A) male gametophyte B) female gametophyte C) male sporophyte D) female sporophyte E) bisexual gametophyte

) Which set contains the most closely related terms? A) megasporangium, megaspore, pollen, ovule B) microsporangium, microspore, egg, ovary C) megasporangium, megaspore, egg, ovule D) microsporangium, microspore, carpel, ovary

Angiosperms are the most successful terrestrial plants. Which of the following features is unique to them and helps account for their success? A) wind pollination B) dominant gametophytes C) fruits enclosing seeds D) embryos enclosed within seed coats E) sperm cells without flagella

Which of the following is found in angiosperms but not in gymnosperms? A) seeds B) pollen C) cones D) microsporangia E) anthers

4) Which of the following statements about double fertilization in angiosperms is correct? A) One pollen grain combines with the egg to form the zygote, and one pollen grain combines with the polar nuclei to form endosperm. Two sperm combine with a polar nucleus to form endosperm. B) Two pollen grains combine with two ovules to form the zygote and endosperm. C) One sperm combines with the polar nuclei to form the zygote, and one sperm combines with the egg to form endosperm. D) One sperm combines with the egg to form the zygote, and one sperm combines with the polar nuclei to form endosperm.

) Microsporangia in flowering plants are located in the _____. A) stamen B) carpel C) petals D) sepals E) receptacle

) _____ prevents seeds from germinating until conditions are favorable for the growth of the plant. A) Ethylene B) Auxin C) Zeaxanthin D) Gibberellin E) Abscisic acid