Name: 
 

Unit 6: Plant Physiology


Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

 1. 
An evolutionary adaptation that increases exposure of a plant to light in a dense forest is
a.
closing of the stomata.
b.
lateral buds.
c.
apical dominance.
d.
absence of petioles.
e.
intercalary meristems.
 

 2. 
One important difference between the anatomy of roots and the anatomy of leaves is that
a.
only leaves have phloem and only roots have xylem.
b.
the cells of roots have cell walls and leaf cells do not.
c.
a waxy cuticle covers leaves but is absent in roots.
d.
vascular tissue is found in roots but is absent from leaves.
e.
leaves have epidermal tissue but roots do not.
 

 3. 
Which of the following is true about secondary growth in plants?
a.
Flowers may have secondary growth.
b.
Secondary growth is a common feature of eudicot leaves.
c.
Secondary growth is produced by both the vascular cambium and the cork cambium.
d.
Primary growth and secondary growth alternate in the life cycle of a plant.
e.
Plants with secondary growth are typically the smallest ones in an ecosystem.
 

 4. 
Axillary buds
a.
are initiated by the cork cambium.
b.
develop from meristematic cells left by the apical meristem.
c.
are composed of a series of internodes lacking nodes.
d.
grow immediately into shoot branches.
e.
do not form a vascular connection with the primary shoot.
 

 5. 
Which of the following is true of bark?
a.
It is composed of phloem plus periderm.
b.
It is associated with annuals but not perennials.
c.
It is formed by the apical meristems.
d.
It has no identifiable function in trees.
e.
It forms annual rings in deciduous trees.
 

 6. 
The polarity of a plant is established when
a.
the zygote divides.
b.
cotyledons form at the shoot end of the embryo.
c.
the shoot-root axis is established in the embryo.
d.
the primary root breaks through the seed coat.
e.
the shoot first breaks through the soil into the light as the seed germinates.
 

 7. 
Which of the following is not a function of the plasma membrane proton pump?
a.
hydrolyzes ATP
b.
produces a proton gradient
c.
generates a membrane potential
d.
equalizes the charge on each side of a membrane
e.
stores potential energy on one side of a membrane
 

 8. 
Which of the following statements about xylem is incorrect?
a.
It conducts material upward.
b.
It conducts materials within dead cells.
c.
It transports mainly sugars and amino acids.
d.
It has a lower water potential than soil does.
e.
No energy input from the plant is required for xylem transport.
 

 9. 
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
 

 10. 
Transpiration in plants requires all of the following except
a.
adhesion of water molecules to cellulose.
b.
cohesion between water molecules.
c.
evaporation of water molecules.
d.
active transport through xylem cells.
e.
transport through tracheids.
 

 11. 
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.
 

 12. 
Which one of the following statements about transport of nutrients in phloem is false?
a.
Solute particles can be actively transported into phloem at the source.
b.
Companion cells control the rate and direction of movement of phloem sap.
c.
Differences in osmotic concentration at the source and sink cause a hydrostatic pressure gradient to be formed.
d.
A sink is that part of the plant where a particular solute is consumed or stored.
e.
A sink may be located anywhere in the plant.
 

 13. 
Organic molecules make up what percentage of the dry weight of a plant?
a.
6%
b.
17%
c.
67%
d.
81%
e.
96%
 

 14. 
What is meant by the term chlorosis?
a.
the uptake of the micronutrient chlorine by a plant
b.
the formation of chlorophyll within the thylakoid membranes of a plant
c.
the yellowing of leaves due to decreased chlorophyll production
d.
a contamination of glassware in hydroponic culture
e.
release of negatively charged minerals such as chloride from clay particles in soil
 

 15. 
Which soil mineral is most likely leached away during a hard rain?
a.
Na+
b.
K+
c.
Ca++
d.
NO3-
e.
H+
 

 16. 
The most efficient way to increase essential amino acids in crop plants for human consumption is to
a.
breed for higher yield of deficient amino acids.
b.
increase the amount of fertilizer used on fields.
c.
use 20-20-20 fertilizer instead of 20-5-5 fertilizer.
d.
engineer nitrogen-fixing nodules into crop plants lacking them.
e.
increase irrigation of nitrogen-fixing crops.
 

 17. 
Hyphae form a covering over roots. Altogether, these hyphae create a large surface area that helps to do which of the following?
a.
aid in absorbing minerals and ions
b.
maintain cell shape
c.
increase cellular respiration
d.
anchor a plant
e.
protect the roots from ultraviolet light
 

 18. 
Carnivorous plants have evolved mechanisms that trap and digest small animals. The products of this digestion are used to supplement the plant's supply of
a.
energy.
b.
carbohydrates.
c.
lipids and steroids.
d.
minerals.
e.
water.
 

 19. 
Which of the following is true in plants?
a.
Meiosis occurs in gametophytes to produce gametes.
b.
Meiosis occurs in sporophytes to produce spores.
c.
The gametophyte is the dominant generation in flowering plants.
d.
Plants exist continually as either sporophytes or gametophytes.
e.
Male gametophytes and female gametophytes have the same structure.
 

 20. 
Where and by which process are sperm produced in plants?
a.
meiosis in pollen grains
b.
meiosis in anthers
c.
mitosis in male gametophytes
d.
mitosis in the micropyle
e.
mitosis in the embryo sac
 

 21. 
The integuments of an ovule function to do what?
a.
protect against animal predation
b.
ensure double fertilization
c.
form a seed coat
d.
both A and B
e.
both A and C
 

 22. 
When seeds germinate, the radicle emerges before the shoot. This allows the seedling to quickly
a.
obtain a dependable water supply.
b.
mobilize stored carbohydrates.
c.
protect the emerging coleoptile.
d.
avoid etiolation.
e.
initiate photosynthesis.
 

 23. 
All of the following could be considered advantages of asexual reproduction in plants except
a.
success in a stable environment.
b.
increased agricultural productivity.
c.
cloning an exceptional plant.
d.
production of artificial seeds.
e.
adaptation to change.
 

 24. 
In modern agriculture, what does "terminator technology" refer to?
a.
introduction of bacterial genes that release insect toxins into plants
b.
introduction of male sterility genes into plants to prevent selfing
c.
introduction of genes into a plant that prevent its seeds from maturing
d.
Bt genes produced in maize pollen
e.
selection of resistant clones following mutator treatment of seeds
 

 25. 
Which of the following statements is (are) true of plants?
a.
Unlike animals, plants cannot respond to stimuli.
b.
Plants are stationary and are incapable of movement.
c.
Plants adjust their growth and development in response to environmental cues.
d.
Only A and B are true.
e.
A, B, and C are true.
 

 26. 
Which of these conclusions is supported by the research of both Went and Charles and Frances Darwin on shoot responses to light?
a.
When shoots are exposed to light, a chemical substance migrates toward the light.
b.
Agar contains a chemical substance that mimics a plant hormone.
c.
A chemical substance involved in shoot bending is produced in shoot tips.
d.
Once shoot tips have been cut, normal growth cannot be induced.
e.
Light stimulates the synthesis of a plant hormone that responds to light.
 

 27. 
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
 

 28. 
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.
 

 29. 
Plant cells begin synthesizing large quantities of heat-shock proteins
a.
after the induction of chaperone proteins.
b.
in response to the lack of CO2 following the closing of stomata by ethylene.
c.
when desert plants are quickly removed from high temperatures.
d.
when they are subjected to moist heat (steam) followed by electric shock.
e.
when the air around species from temperate regions is above 40°C.
 

 30. 
The transduction pathway that activates systemic acquired resistance in plants is initially signaled by
a.
antisense RNA.
b.
Pfr phytochrome.
c.
salicylic acid.
d.
abscisic acid.
e.
red, but not far-red, light.
 



 
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