Christmas cactus, or Schlumbergera, has showy red flowers

26 Jun Christmas cactus, or Schlumbergera, has showy red flowers

Question
Section 1: MULTIPLE CHOICE

Choose the best answer for each of the following. [1pt each]

1. Christmas cactus, or Schlumbergera, has showy red flowers. Though known as “Flor de Maio”, or May flower, in Brazil where it is found in nature, this popular houseplant starts flowering in midDecember in the Northern Hemisphere. Experiments show that it has a critical daylength of 12 hours. What can you conclude about regulation of flowering in this plant?

.0/msohtmlclip1/01/clip_image002.jpg” alt=”Macintosh hd:users:eirish:desktop:christmas-cactus1.jpg”>A. It is a short day plant.

B. It is a long day plant.

C. It is a short night plant.

D. It is day neutral.

E. It requires chilling before it can flower.

2. It should be possible to “trick” a Christmas cactus to delay its blooming for Valentine’s Day (February 14). Which of the following would be the best way to do this? (Additional information: the autumnal equinox is September 22).

A. Move the plant into the refrigerator for 2 months, starting in October.

B. Make sure the plant gets at least 13 hours of light every day, starting at the middle of September, until the middle of November, and then give it no more than 11 hours of light.

C. Keep the plant in 24 hour light until Groundhog’s Day (Feb. 2), and then transfer it to 12-hour days.

D. Make sure the plant gets at least 13 hours of light, starting at the beginning of September, until February, and then give it no more than 11 hours of light.

E. Grow the plant on a windowsill with no artificial light until September 22. Then, keeping it in the window, give it a flash of far red light at midnight every day until the middle of December, and then provide natural lighting after that.

3. Many plants defend themselves against herbivory by producing toxins. Since compounds that are toxic to animals are also usually toxic to plants, plants must have strategies to avoid being poisoned by their own biochemistry. These strategies include:

A. Isolation of toxins in special compartments

B. Production of the toxin only after cell damage has occurred.

C. Modification of the plant’s enzymes or receptors so that the toxin is ineffective in that plant.

D. A and B

E. All of the above.

4. Tissue damage from insects chewing on a leaf can cause the whole plant to ramp up production of compounds that deter herbivory. The steps that lead to this defense response, in order, are:

A. activated receptor induces jasmonate production, jasmonate moves through the phloem stream, jasmonate binds transcriptional repressor, transcription factor promotes synthesis of protease inhibitor, production of elicitor, elicitor binds receptor

B. production of elicitor, elicitor binds receptor, activated receptor induces jasmonate production, jasmonate binds transcriptional repressor, jasmonate moves through the phloem stream, transcription factor promotes synthesis of protease inhibitor

C. production of elicitor, elicitor binds receptor, activated receptor induces jasmonate production, jasmonate moves through the phloem stream, jasmonate binds transcriptional repressor, transcription factor promotes synthesis of protease inhibitor

D. transcription factor promotes synthesis of protease inhibitor, production of elicitor, elicitor binds receptor, activated receptor induces jasmonate production, jasmonate binds transcriptional repressor, jasmonate moves through the phloem stream

E. transcription factor promotes synthesis of protease inhibitor, production of elicitor, elicitor binds receptor, activated receptor induces jasmonate production, jasmonate moves through the phloem stream, jasmonate binds transcriptional repressor

5. You can find plants growing almost anywhere, including on land that is very dry. Which of the following is not found in plants adapted live in arid environments?

A. Stomata tucked away in cavities or crypts on leaves.

B. Aerenchyma, a tissue that stores oxygen

C. Deep roots for collecting water far underground

D. A thick cuticle and dense trichomes (hairs) on leaf surfaces

E. Succulence, the storage of water in leaves or stems

6. A vegetative shoot apical meristem is converted to the production of floral organs instead of leaves by the presence of a compound known as florigen. Which of the following steps is not involved in florigen action?

A. CO promotes the synthesis of the transcription factor FT in the SAM.

B. FT forms a dimer with FD in the SAM.

C. Inductive photoperiod stabilizes the transcription factor CO in leaf phloem.

D. FT moves via the phloem to the SAM.

E. FT + FD promote the transcription of AP1, which results in sepal formation.

7. Plants grow toward the light (phototropism) and against gravity as a result of asymmetric growth stimulated by redistribution of the hormone

A. Ethylene

B. Abscisic acid

C. Auxin

D. Gibberellic acid

E. Cytokinin

8. Nodulation is an adaptation that allows some plants to survive growing on soils poor in

A. Carbon

B. Iron

C. Nitrogen

D. Magnesium

E. Boron

9. The size of the openings that allow gas exchange for photosynthesis, the stomata, is regulated. Which of the following is not important for opening the stomata?

A. Cell wall reinforcements that make the guard cells curve when they fill with water

B. Blue light receptors on the plasma membrane of guard cells that activate a proton pump

C. An increase in water potential when proton export triggers an influx of K+ and Cl- ions in guard cells

D. Chloroplasts in guard cells, which start producing sugars when leaves are exposed to light.

E. All of the above are important (changed at exam)

10. Eukaryotes often engulf bacteria and other single cells in order to acquire nutrients, but sometimes the engulfed cell persists, which leads an endosymbiosis. Which of the following is not an example of endosymbiosis in eukaryotes?

A. Uptake of a proteobacterium that became mitochondria

B. Uptake of cyanobacteria that became chloroplasts in the ancestors of green plants

C. Uptake of red algae that became the chloroplasts of brown algae

D. Uptake of Rhizobium in root cortex cells of legumes

E. All of the above are examples of ancient or modern endosymbiosis.

11. Eukaryotic cells exhibit of number of features absent from prokaryotes which permitted great diversification of form. Which of the following is not important in this process?

A. Cytoskeleton upon which vesicles can move through the cell

B. Cytoskeleton that allows cells to change shape

C. Endosymbiosis leading to energy organelles

D. Microtubules for accurate segregation of multiple chromosomes at cell division

E. None of the above—they are all important.

12. Sexual reproduction increases diversity in a population by all of the following except:

A. Reassortment of alleles on a chromosome

B. Increasing chromosome number in each sexual generation

C. Blending of genomes from two different parents

D. Promoting heterozygosity that can mask deleterious mutations

E. All of the above increase diversity in a population

13. The space between neighboring cell membranes in epithelial tissue has been experimentally demonstrated to be largely due to the type of ___________ in these cells.

A. actins

B. cell adhesion molecules (CAMs)

C. integrins

D. kinases

E. myosins

14. Which component of a feedback mechanism is responsible for evaluating sensory inputs and then triggering appropriate responses?

A. Effector

B. Integrator

C. Sensor

D. All of the above

E. None of the above