Plant Biology Exam 3 Number 2

Front 1

1. When a particular trait appears in the F2 generation but not in the F1 generation, it is an indication that:

a. a monohybrid cross is involved.
b. a dihybrid cross is involved.
c. true-breeding plants are involved.
d. the trait is recessive.
e. the trait is dominant.

Back 1

D. the trait is recessive

Front 2

2. If a plant has a trait with the genetic constitution Bb, then:

a. its phenotype is blue.
b. its genotype is blue.
c. the plant is homozygous for that trait.
d. the plant is heterozygous for that trait.
e. the plant has two identical alleles for that trait.

Back 2

D. the plant is heterozygous for that trait

Front 3

3. If we say that the phenotype of an individual is purple, we are saying that:

a. the appearance of the individual is purple.
b. the genetic constitution of the individual is purple.
c. the individual is homozygous.
d. the individual is heterozygous.
e. purple is the dominant allele.

Back 3

a. the appearance of the individual is purple

Front 4

4. In peas, green pod color is dominant over yellow pod color. If a plant heterozygous for pod color is crossed with a plant homozygous recessive for pod color, what phenotypes would you expect in the offspring?

a. All with green pods
b. All with yellow pods
c. Half with green pods and half with yellow pods
d. Three-quarters with green pods and 1/4 with yellow pods
e. One-quarter with green pods and 3/4 with yellow pods

Back 4

C. Half the green pods and half with yellow pods

Front 5

5. If W represents the allele for purple flower color, and w represents the allele for white flower color, what genotypic ratio would you expect in the offspring of a cross between two heterozygous plants?

a. One WW: one ww
b. One WW: two Ww: one ww
c. Three WW: one ww
d. One WW: three ww
e. Three WW: two Ww: one ww

Back 5

B. One WW:two Ww: one ww

Front 6

6. If W represents the allele for purple flower color, and w represents the allele for white flower color, what phenotypic ratio would you expect for the offspring of a testcross?

a. One WW: one ww
b. One WW: two Ww: one ww
c. Three WW: one ww
d. One WW: three ww
e. Three WW: two Ww: one ww

Back 6

a. One WW: one ww

Front 7

7. Humans breed plants and animals through the process of:
a. artificial selection.
b. natural selection.
c. survival of the fittest.
d. evolution.
e. mutation.

Back 7

a.artifical selection

Front 8

8. ______ is the sum total of all the alleles of all the genes in a population.

a. The genotype
b. The gene pool
c. Evolution
d. Population genetics
e. A species

Back 8

B. the gene pool

Front 9

9. The sole criterion for the fitness of an individual is ______ relative to that of other individuals.

a. its strength
b. its beauty
c. its resistance to disease
d. the size of its gene pool
e. the number of its surviving offspring

Back 9

e. the number of its surviving offspring

Front 10

10. In a population that is in Hardy-Weinberg equilibrium, the frequency of a particular dominant allele is 60 percent, and the frequency of the recessive allele is 40 percent. In the next generation, the frequency of the dominant allele will be ______ percent and the frequency of the recessive allele will be ______ percent.

a. 70; 30
b. 60; 40
c. 50; 50
d. 40: 60
e. 30; 70

Back 10

B. 60; 40

Front 11

11. The raw material for evolutionary change is provided by:a. sexual reproduction.
b. asexual reproduction.
c. mutations.
d. meiosis.
e. mitosis.

Back 11

c. mutations

Front 12

12. In a population, ______ results from the immigration or emigration of individuals.

a. mutation
b. genetic drift
c. gene flow
d. natural selection
e. nonrandom mating

Back 12

c. gene pool

Front 13

13. An example of ______ is when a single plant seed initiates a new population.

a. nonrandom mating
b. natural selection
c. fitness
d. the founder effect
e. the bottleneck effect

Back 13

d. the founder effect

Front 14

14. As an example of rapid evolutionary change, one variety of Agrostis grows much faster on tailings and dumps around abandoned lead mines than does another variety. What is the explanation for this?

a. The high lead content of the soil causes an increase in the mutation rate.
b. Lead stimulates the growth of plants.
c. Selection has favored the development of the lead-resistant variety.
d. Selection has favored the development of the lead-sensitive variety.
e. Lead stimulates the production of poisons that protect the plants against predators.

Back 14

c. selection has favored the development of the lead-resistant variety

Front 15

15. If two groups are genetically isolated from each other, then by definition:

a. the two groups look different.
b. one group cannot exchange genes with the other group.
c. one group lives longer than the other.
d. one group is more fit than the other group.
e. gene flow occurs between the two groups.

Back 15

b. one ground cannot exchange genes with the other group

Front 16

16. Allopatric speciation is different from sympatric speciation in that allopatric speciation involves:

a. polyploidy.
b. geographic isolation.
c. hybridization.
d. nondisjunction during meiosis.
e. nondisjunction during mitosis.

Back 16

b. geographic isolation

Front 17

17. A(n) ______ includes, by definition, all the organisms in a particular place together with their environment.

a. community
b. ecosystem
c. population
d. species
e. mutualistic interaction

Back 17

b. ecosystem

Front 18

18. A community consists of all the ______ in a particular area.

a. individuals of a single species
b. plants
c. plants and animals
d. organisms
e. organisms and their environment

Back 18

d. organisms

Front 19

19. When the two species are grown together, Lemna polyrhiza is replaced by Lemna gibba because L. gibba outcompetes L. polyrhiza for:

a. light.
b. space.
c. carbon dioxide.
d. oxygen.
e. minerals.

Back 19

a. light

Front 20

20. In an ecosystem, energy flows from:

a. consumers to autotrophs to decomposers.
b. decomposers to consumers to autotrophs.
c. autotrophs to consumers to decomposers.
d. consumers to decomposers to autotrophs.
e. autotrophs to decomposers to consumers.

Back 20

c. autotrophs to consumers to decomposers

Front 21

21. Competition occurs, by definition, when two individuals living in the same area:

a. belong to the same species.
b. belong to the same population.
c. require the same limiting resource.
d. photosynthesize at the same rates.
e. allocate energy in the same way.

Back 21

c. require the same limiting resource

Front 22

22. The two climatic factors affecting the distribution of biomes are:

a. fire and precipitation.
b. temperature and precipitation.
c. precipitation and air currents.
d. air currents and carbon dioxide.
e. carbon dioxide and oxygen.

Back 22

b. temperature and precipitation

Front 23

23. Along the Pacific Coast of the United States, the “rain shadow” is the ______ area on the ______ slope of the Sierra Nevada.

a. dry; eastern
b. dry; western
c. moist; eastern
d. moist; western
e. moist; southern

Back 23

b. dry; western

Front 24

24. All of the following are adaptations of desert plants EXCEPT:

a. the ability to carry out CAM photosynthesis.
b. the ability to carry out C4 photosynthesis.
c. the ability to complete their life cycles before soil moisture is depleted.
d. the ability to tap water deep in the ground.
e. the ability to store water in special tissues.

Back 24

d. the ability to tap water deep in the ground

Front 25

25. The O2 evolved in photosynthesis comes from:

a. carbon dioxide.
b. water.
c. glucose.
d. (CH2O).
e. (C3H3O3).

Back 25

b. water

Front 26

26. Chlorophyll absorbs light principally in the ______ wavelengths.

a. blue and green
b. green and violet
c. blue and violet
d. violet and green
e. green and red

Back 26

c. blue and violet

Front 27

27. Chlorophyll appears green because it:

a. absorbs green light.
b. absorbs and reflects green light.
c. absorbs and transmits green light.
d. reflects and transmits green light.
e. transmits violet light.

Back 27

d. reflects and transmits green light

Front 28

28. How many photons are required for photolysis to yield one molecule of O2 gas?a. one
b. two
c. three
d. four
e. five

Back 28

d. four

Front 29

29. The reduction of NADP+ is associated with:

a. Photosystem I.
b. Photosystem II.
c. the photosynthetic electron transport chain.
d. cyclic electron flow.
e. the water-splitting enzyme

Back 29

a. Photosystem I

Front 30

30. The Calvin cycle takes place in the:

a. lumen of the thylakoid.
b. chloroplast stroma.
c. thylakoid membrane.
d. cytoplasm.
e. mitochondrial matrix.

Back 30

B. chloroplast stroma

Front 31

31. Rubisco can use ______ or CO2 as a substrate.

a. 3-phosphoglycerate
b. O2
c. glyceraldehyde 3-phosphate
d. serine
e. oxaloacetate

Back 31

b. O2

Front 32

32. Water potential is defined as the:

a. tendency of water to enter a cell.
b. tendency of water to leave a cell.
c. mechanical energy of water.
d. kinetic energy of water.
e. potential energy of water.

Back 32

e. potential energy of water

Front 33

33. In the absence of other factors affecting water potential, water will move FROM a region of ______ TO a region of ______.

a. low water concentration; high water concentration
b. low solute concentration; high solute concentration
c. low water potential; high water potential
d. low potential energy; high potential energy
e. low pressure; high pressure

Back 33

b. low solute concentration; high solute concentration

Front 34

34. Which of the following could be the water potential of a sucrose solution at atmospheric pressure and at sea level?

a. 100 MPa
b. 100 bars
c. 10 bars
d. 0 bars
e. –10 MPa

Back 34

e. -10 MPa

Front 35

35. If a plant cell is placed in an solution with a relatively low water potential, the cell will:

a. swell and perhaps burst.
b. undergo plasmolysis.
c. build up turgor pressure.
d. build up wall pressure.
e. neither gain nor lose water.

Back 35

b. undergo plasmolysis

Front 36

36. A plant loses the greatest amount of water through the:

a. leaf cuticle.
b. stem cuticle.
c. root cuticle.
d. stomata.
e. lenticels.

Back 36

d. stomata

Front 37

37. The rate of transpiration is affected by stomatal movements and:

a. air currents only.
b. humidity only.
c. temperature only.
d. temperature and air currents only.
e. temperature, humidity, and air currents.

Back 37

e. temperature, humidity, and air currents.

Front 38

38. Which of the following indicates the correct sequence of tissues through which water moves from the soil into the root?

a. Root hairs, endodermis, vascular cylinder, cortical cells
b . Root hairs, endodermis, cortical cells, vascular cylinder
c. Endodermis, epidermis, vascular cylinder, cortical cells
d. Epidermis, cortical cells, endodermis, vascular cylinder
e. Epidermis, endodermis, cortical cells, vascular cylinder

Back 38

d. Epidermis, cortical cells, endodermis, vascular cylinder.

Front 39

39. As a consequence of girdling a tree:

a. its leaves stop exporting solutes.
b. its leaves stop importing solutes.
c. the bark above the girdle swells.
d. the bark above the girdle dies.
e. the bark begins to act as a source.

Back 39

c. the bark above the girdle swells.

Front 40

40. All plant hormones:

a. are equally effective in free and bound forms.
b. act in the tissues where they are produced.
c. are stimulatory.
d. are active in large quantities.
e. communicate information.

Back 40

e. communciate information

Front 41

40. All plant hormones:

a. are equally effective in free and bound forms.
b. act in the tissues where they are produced.
c. are stimulatory.
d. are active in large quantities.
e. communicate information.

Back 41

e. communicate information

Front 42

41. ______ are recently discovered polypeptides that activate chemical defenses against herbivores.

a. Systemins
b. Auxins
c. Brassinolides
d. Salicylic acids
e. Jasmonates

Back 42

a. systemins

Front 43

42. Cytokinins are synthesized in ____ and transported from there to all other parts of the plant.

a. stems
b. shoot apical meristems
c. leaves
d. roots
e. fruits

Back 43

d. roots

Front 44

43. Dwarf mutant plants are short because they:

a. synthesize too much gibberellin.
b. synthesize too much abscisic acid.
c. cannot synthesize ethylene.
d. cannot synthesize auxin.
e. cannot synthesize gibberellin.

Back 44

e. cannot syntheisze gibberellin

Front 45

44. Which of the following statements about tropisms is FALSE?

a. They are growth responses.
b. They are responses to an external stimulus.
c. They are directional responses.
d. Responses involve bending or curving.
e. Positive responses are away from the stimulus.

Back 45

e. positive responses are away from the stimulus

Front 46

45. Circadian rhythms have cycles of approximately:

a. 12 minutes.
b. 1 hour.
c. 24 hours.
d. 1 month.
e. 12 months

Back 46

c. 24 hours

Front 47

46. What is responsible for keeping a plant’s circadian rhythm in step with the natural day-night cycle?

a. An endogenous timing mechanism
b. Auxin
c. Phototropism
d. The environment
e. The plant’s biological clock

Back 47

d. the environment

Front 48

47. Photoperiodism is the biological response to changes in:

a. daylength.
b. intensity of light.
c. wavelength of light.
d. seasons.
e. temperature.

Back 48

a. daylength

Front 49

48. Long-day plants flower:

a. in the summer.
b. in early spring or fall.
c. when exposed to eight hours of daylight.
d. when the light period is shorter than a critical length.
e. without respect to daylength.

Back 49

a. in the summer

Front 50

49. If a short-day plant receives a one-minute exposure to light in the middle of the dark period rather than continuous darkness, it will:

a. produce more flowers.
b. produce smaller flowers
c. produce larger flowers.
d. flower at a lower temperature.
e. not flower.

Back 50

e. not flower

Front 51

50. Rainfall will break seed dormancy in certain desert species by:

a. abrading the seed coat.
b. leaching away inhibitory chemicals.
c. dissolving waxy substances.
d. making the seed coat permeable to nutrients.
e. making the seed coat permeable to oxygen.

Back 51

b. leaching away inhibitory chemicals