Plant Biology

1. Plant Biology • Plant Cell • Evolution • Life Cycles • Structures • Transport • Hormones • Tropisms • Photoperiodism

2. A botanist discovers a new species of plant in a tropical rain forest. After observing its anatomy and life cycle, the following characteristics are noted: flagellated sperm, xylem with tracheids, separate gametophyte and sporophyte phases, and no seeds. This plant is probably most closely related to * • mosses. • Chara. • ferns. • liverworts. • flowering plants.

3. A botanist discovers a new species of plant with a dominant sporophyte, chlorophyll a and b, and a cell wall made of cellulose. In assigning this plant to a division, all of the following would provide useful information except whether or not the plant has * • endosperm. • seeds. • flagellated sperm. • flowers. • starch.

4. Assume that a botanist was visiting a tropical region for the purpose of discovering plants with medicinal properties. All of the following might be ways of identifying potentially useful plants except • observing which plants sick animals seek out. • observing which plants are the most used food plants. • observing which plants animals do not eat. • collecting plants and subjecting them to chemical analysis. • asking local people which plants they use as medicine.

5. What is one result of an organism having meristems? • a rapid change from juvenile to adult state • a seasonal change in leaf morphology • a rapid change from a vegetative state to a reproductive state • indeterminate, life-long growth • production of a fixed number of segments during growth

6. One important difference between the anatomy of roots and the anatomy of leaves is that • only leaves have phloem and only roots have xylem. • the cells of roots have cell walls that are lacking in leaf cells. • a waxy cuticle covers leaves but is absent in roots. • vascular tissue is found in roots but is absent from leaves. • leaves have epidermal tissue but roots do not.

7. While studying the plant Arabidopsis, a botanist finds that an RNA probe produces colored spots in the sepals of the plant. From this information, which information can be inferred? • The differently colored plants will attract different pollinating insects. • The RNA probe is transported only to certain tissues. • The colored regions were caused by mutations that took place in the sepals. • The RNA probe is specific to a gene active in sepals. • More research needs to be done on the sepals of Arabidopsis.

8. Which of these statements about human evolution is true? • The ancestors of Homo sapiens were chimpanzees and other apes. • Human evolution has proceeded in an orderly fashion from an ancestral anthropoid to Homo sapiens. • The evolution of upright posture and enlarged brain occurred simultaneously. • Different features have evolved at different rates. • Mitochondrial DNA analysis indicates that modern humans are genetically very similar to Neanderthals.

9. What mechanism explains the movement of sucrose from source to sink? • evaporation of water and active transport of sucrose from the sink • osmotic movement of water into the sucrose-loaded sieve-tube members creating a higher hydrostatic pressure in the source than in the sink • tension created by the differences in hydrostatic pressure in the source and sink • active transport of sucrose through the sieve-tube cells driven by proton pumps • the hydrolysis of starch to sucrose in the mesophyll cells that raises their water potential and drives the bulk flow of sap to the sink

10. The main mechanism(s) determining the direction of short-distance transport within a potato tuber is (are) • diffusion due to concentration differences and bulk flow due to pressure differences. • pressure flow through the phloem. • active transport due to the hydrolysis of ATP and ion transport into the tuber cells. • determined by the structure and function of the tonoplast of the tuber cells. • not affected by temperature and pressure.

11. A water molecule could move all the way through a plant from soil to root to leaf to air and pass through a living cell only once. This living cell would be a part of which structure? • the Casparian strip • a guard cell • the root epidermis • the endodermis • the root cortex

12. Photosynthesis begins to decline when leaves wilt because • flaccid cells are incapable of photosynthesis. • CO2 accumulates in the leaves and inhibits photosynthesis. • there is insufficient water for photolysis during light reactions. • stomata close, preventing CO2 entry into the leaf. • the chlorophyll of flaccid cells cannot absorb light.

13. Water flows into the source end of a sieve tube because • sucrose has diffused into the sieve tube, making it hypertonic. • sucrose has been actively transported into the sieve tube, making it hypertonic. • water pressure outside the sieve tube forces in water. • the companion cell of a sieve tube actively pumps in water. • sucrose has been dumped from the sieve tube by active transport.

14. In the pressure-flow hypothesis of translocation, what causes the pressure? • root pressure • the osmotic uptake of water by sieve tubes at the source • the accumulation of minerals and water by the stele in the root • the osmotic uptake of water by the sieve tubes of the sink • hydrostatic pressure in xylem vessels

15. What does self-incompatibility provide for a plant? • means of transferring pollen to another plant • a means of coordinating the fertilization of an egg with the development of stored nutrients • a means of destroying foreign pollen before it fertilizes the egg cell • a biochemical block to self-fertilization so that cross-fertilization is assured • a means of producing seeds without the need for fertilization

16. What is the relationship between pollination and fertilization in flowering plants? * • Fertilization precedes pollination. • Pollination easily occurs between plants of different species. • Pollen is formed within megasporangia so that male and female gametes are near each other. • Pollination brings gametophytes together so that fertilization can occur. • If fertilization occurs, pollination is unnecessary.

17. The heavy line in this figure illustrates the relationship between auxin concentration and cell growth in stem tissues. If the same range of concentrations was applied to lateral buds, what curve would probably be produced? * • I only • II only • III only • II and III • either I or III

18. A botanist exposed two groups of plants (of the same species) to two photoperiods, one with 14 hours of light and 10 hours of dark and the other with 10 hours of light and 14 hours of dark. Under the first set of conditions, the plants flowered, but they failed to flower under the second set of conditions. Which of the following conclusions would be consistent with these results? • The critical night length is 14 hours. • The plants are short-day plants. • The critical day length is 10 hours. • The plants can convert phytochrome to florigen. • The plants flower in the spring.

19. AP Essays and labs AP Lab 9 2005, # 3

20. Ecology • Biomes • Behavior • Populations • Community • Symbiosis • Competition • Succession • Ecosystems

21. If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced sunlight reaching Earth's surface by 70% for one year, all of the following marine communities would be greatly affected except a • deep-sea vent community. • coral reef community. • benthic community. • pelagic community. • estuary community.

22. When, during a field trip, the instructor touched the body of a moth that was sitting on a tree trunk, the moth raised its forewings to reveal large eye-spots on its hind wings. The instructor asked the class why the moth lifted its wings. One student said that certain sensory receptors had fired and triggered a neuronal reflex culminating in the contraction of certain muscles. A second student responded that the behavior might frighten would-be predators.

23. (cont.) What can you say about the explanations of these two students? * • The first response is correct, while the second is incorrect. • The first response answers a proximate question, while the second answers an ultimate question. • The first response is biological, while the second is philosophical. • The first explanation is testable as a scientific hypothesis, while the second is not. • Both explanations are reasonable and simply represent a difference of opinion.

24. A cage with male mosquitoes in it has a small earphone placed on top, through which the sound of a female mosquito is played. All the males immediately fly to the earphone and thrust their abdomens through the fabric of the cage.

25. (cont.) Which of the following best describes this? • The males learn to associate the sound with a female and are thus attracted to it. • Copulation is a fixed action pattern, and the female flight sound is a sign stimulus that initiates it. • The sound from the earphone irritated the male mosquitoes, causing them to attempt to sting it. • The reproductive drive is so strong that when males are deprived of females, they will attempt to mate with anything that has even the slightest female characteristic. • Through classical conditioning, the male mosquitoes have associated the inappropriate stimulus from the earphone with the normal response of copulation.

26. Which of the following is true about imprinting? • It may be triggered by visual or chemical stimuli. • It happens to many adult animals, but not to their young. • It is a type of learning involving no innate behavior. • It occurs only in birds. • It causes behaviors that last for only a short time (the critical period).

27. Every morning at the same time John went into the den to feed his new tropical fish. After a few weeks John noticed that the fish would rise to the top of the tank as soon as he would enter the room. This is a good example of • habituation. • imprinting. • classical conditioning. • operant conditioning. • maturation.

28. A dog learns that it will get a treat when it barks. Which of the following might you use to describe this behavior? • The dog is displaying an instinctive fixed action pattern. • The dog is performing a social behavior. • The dog is trying to protect its territory. • The dog has been classically conditioned. • The dog's behavior is a result of operant conditioning.

29. As N approaches K for a certain population, which of the following is predicted by the logistic equation? • The growth rate will not change. • The growth rate will approach zero. • The population will show an Allee effect. • The population will increase exponentially. • The carrying capacity of the environment will increase.

30. In which of the following habitats would you expect to find the largest number of K-selected individuals? • an abandoned field in Ohio • the sand dunes south of Lake Michigan • the rain forests of Brazil • south Florida after a hurricane • a newly emergent volcanic island

31. The following question refers to the figure below, which depicts the age structure of three populations

32. Assuming these age structure diagrams describe human populations, in which population is unemployment likely to be most severe in the future? • I • II • III • No differences in the magnitude of future unemployment would be expected among these populations. • It is not possible to infer anything about future social conditions from age structure diagrams.

33. Which of the following variables is (are) important in contributing to the rapid growth of human populations? • the high percentage of young people • the average age to first give birth • carrying capacity of the environment • only A and B • A, B, and C

34. Clear-cutting tropical forests yields agricultural land with limited productivity because • it is too hot in the tropics for most food crops. • the tropical forest regrows rapidly and chokes out agricultural crops. • few of the ecosystem’s nutrients are stored in the soil; most are in the forest trees. • phosphorus, not nitrogen, is the limiting nutrient in those soils. • decomposition rates are high but primary production is low in the tropics.

35. Use the figure below to answer the following questions (2 and 3). Examine this food web for a particular terrestrial ecosystem. Each letter is a species. The arrows represent energy flow. Which species is autotrophic? A B C D E

36. Species C makes its predators sick. Which species is most likely to benefit from being a mimic of C? * • A • B • C • D • E

37. If the flow of energy in an Arctic ecosystem goes through a simple food chain from seaweeds to fish to seals to polar bears, then which of the following is true? • Polar bears can provide more food for Eskimos than seals can. • The total energy content of the seaweeds is lower than that of the seals. • Polar bear meat probably contains the highest concentrations of fat-soluble toxins. • Seals are more numerous than fish. • The carnivores can provide more food for the Eskimos than the herbivores can.

38. AP Labs and Essays Lab 12 Lab 11 1997, # 1 1997, # 3 (lab) 1998, # 4 2002, # 2 2003, # 3

39. Cell Parts • Prokaryote • Animal / Plant Cells • Endosymbiotic Hypothesis, • Structures and Functions

40. Evolution • Lamarck/ vs. Darwin • Evidence • Homologous vs. Analogous • Mechanisms • Natural Selection • Genetic drift • Gene Flow • Mutations • Non-Random Mating

41. Populations (Hardy Weinberg) • Speciation, Reproductive isolation • Adaptive Radiation • Modes of Natural Selection

42. Mice that are homozygous for a lethal recessive allele die shortly after birth. In a large breeding colony of mice, you find that a surprising 5% of all newborns die from this trait. In checking lab records, you discover that the same proportion of offspring have been dying from this trait in this colony for the past three years. (Mice breed several times a year and have large litters.) How might you explain the persistence of this lethal allele at such a high frequency? • Homozygous recessive mice have a reproductive advantage. • A large mutation rate keeps producing this lethal allele. • There is some sort of heterozygote advantage and perhaps selection against the homozygous dominant trait. • Genetic drift has kept the recessive allele at this high frequency in the population. • Since this is a diploid species, the recessive allele cannot be selected against when it is in the heterozygote.

43. Genetic analysis of a large population of mink inhabiting an island in Michigan revealed an unusual number of loci where one allele was fixed. Which of the following is the most probable explanation for this genetic homogeneity? * • The population exhibited nonrandom mating, producing homozygous genotypes. • The gene pool of this population never experienced mutation or gene flow. • A very small number of mink may have colonized this island, and this founder effect and subsequent genetic drift could have fixed many alleles. • Natural selection has selected for and fixed the best adapted alleles at these loci. • The colonizing population may have had much more genetic diversity, but genetic drift in the last year or two may have fixed these alleles by chance.

44. Increased UV irradiation causes the skin of humans to become more darkly pigmented over a period of days. The notion that the offspring of such tanned individuals should consequently inherit darkened skin from their parents is consistent with the ideas of • Charles Darwin. • Carolus Linnaeus. • Alfred Wallace. • Jean Baptiste Lamarck. • Charles Lyell.

45. A biologist studied a population of squirrels for 15 years. Over that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of competition for food and predation. Suddenly, the population increased to 80. In a single generation, 90% of the squirrels that were born lived to reproduce. What inferences might you make about that population? • The amount of available food probably increased. • The number of predators probably decreased. • The young squirrels in the next generation will show greater levels of variation than in the previous generations because squirrels that would not have survived in the past are now surviving. • All three of these are reasonable inferences. • Only B and C are reasonable inferences.

46. In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish, i.e., they locate their prey by sight. If a population of algae eaters experiences predation pressure from pike-cichlids, then which of the following should not be observed in the algae-eater population over the course of many generations? • Coloration of the algae eaters may become drab. • The algae eaters may become nocturnal (active only at night). • Female algae eaters may become larger, bearing broods composed of more, and larger, young. • The algae eaters may become sexually mature at smaller overall body sizes. • The algae eaters may become faster swimmers.

47. When chemicals are used to control unwanted organisms, then the wisest application strategy, in light of natural selection and assuming that chemicals generally have negative effects on the environment, is to apply • a large dose of a single chemical. • a small dose of a single chemical. • a moderate dose of a single chemical. • large doses of several different chemicals. • moderate doses of several different chemicals.

48. As adults, certain species of whales possess baleen instead of teeth. Baleen is used to filter the whales' diet of planktonic animals from seawater. As embryos, baleen whales possess teeth, which are later replaced by baleen. The teeth of embryonic baleen whales are evidence that • all whales are the descendants of terrestrial mammals. • baleen whale embryos pass through a stage when they resemble adult toothed whales. • baleen whales are descendants of toothed whales. • ontogeny recapitulates phylogeny. • among ancient whales, baleen evolved before teeth.

49. A botanist identifies a new species of plant that has 32 chromosomes. It grows in the same habitat with three similar species: species A (2n 5 14), species B (2n 5 16), and species C (2n 5 18). Suggest a possible speciation mechanism for the new species. • allopatric divergence by development of a reproductive isolating mechanism. • change in a key developmental gene that causes the plants to flower at different times. • autopolyploidy, perhaps due to a nondisjunction in the formation of gametes of species B. • allopolyploidy, a hybrid formed from species A and C. • Either answer c or d could account for the formation of this new plant species

50. The following question refers to this information: In the year 2500, five male space colonists and five female space colonists from Earth settle on an uninhabited Earthlike planet in the Andromeda galaxy. The colonists and their offspring randomly mate for generations. All ten of the original colonists had free ear lobes, and two are heterozygous for that trait. The allele for free ear lobes is dominant to the allele for attached ear lobes