Question 1

In the ABC model of floral determination, a different combination of the three genes specifies each floral organ.Which gene works in combination with the other two?

Accepted Answer

B

Question 2

How could you monitor flower determination in a plant that is mutant for all three class E SEP genes?

Accepted Answer

Class E SEP genes are essential for the proper development of floral organs, but monitoring flower determination can still be done by measuring levels of early flower determination proteins such as LEAFY and AP1, which act upstream of SEP genes.

Question 3

Why do many plants use the photoperiodic pathway to regulate the timing of flower formation?

Accepted Answer

The photoperiodic pathway allows plants to link flowering to day length, which corresponds to the season when conditions are optimal. This ensures that the plants flower at a time when there will be sufficient light and warmth for successful reproduction.

Question 4

Which of the following is NOT a floral structure?

Accepted Answer

Endosperm is not a floral structure because it is a tissue that develops from the fusion of a male gamete with two female gametes, and is not part of the flower.

Question 5

At the Beautiful Mutants Flower Shop, a variety of unique mutant plants are sold.What would be the best flower to give to a friend who is allergic to pollen?

Accepted Answer

"Beautiful Innocence" is the best choice as it has a mutation in the class C genes which affect the production of pollen. Therefore, it is less likely to cause an allergic reaction in your friend.

Question 6

Which of the following statements about flowering plants is TRUE?

Accepted Answer

A short-day plant requires nights longer than a certain critical period to trigger flowering.

Question 7

Angiosperms use which temporary reproductive structures that are not present in any other group of plants?

Accepted Answer

Flowers are unique to angiosperms and serve as their reproductive structures, unlike cones, carpels, or receptacles.

Question 8

Interrupting the night with a flash of light can trigger flowering in a long-day plant.Why doesn't introducing a short period of darkness during the day cause a short-day plant to flower?

Accepted Answer

A brief dark period during the day is not sufficient to trigger flowering in short-day plants because they require a longer uninterrupted night period to initiate flowering.

Question 9

Your botany instructor likes to tell nerdy jokes, like this: "I wanted to buy a pink Toyota Corolla, but the dealer only had a green Calyx available." Impress your instructor with a clever response to this joke.

Accepted Answer

The answer of Your botany instructor likes to tell nerdy...

Question 10

You buy a Schlumbergera plant, also known as a Christmas Cactus, to decorate the desk where you study late into the night.It is now December, and there are no signs of flower buds forming.What is the most plausible explanation for the lack of flowers?

Accepted Answer

Flowering in Schlumbergera plants is indeed controlled by day length and temperature. The warm room and extended exposure to light are preventing flower formation as this plant requires a period of darkness for a certain amount of time to initiate flower bud formation.

Question 11

Your friend examines an ivy vine growing on the side of a campus building and says, "Look - some of the branches on this plant have a different morphology.The leaf shapes and patterning are different, and there are flowers on some branches but not others.There must have been a mutation!" You respond,

Accepted Answer

The observation of different leaf shapes and patterning and the presence of flowers on some branches but not others are indicative of phase change. This is a natural developmental process in which a plant transitions from its juvenile form to its adult form, becoming competent to respond to flowering signals. It does not necessarily involve a mutation in a specific gene or an overexpression of a gene. The changes in morphology are not necessarily evidence that the plant's environment has changed during its lifetime, although environmental factors can affect plant development.

Question 12

The owner of a plant nursery is introducing the new night janitor to his duties."Behind this door are the poinsettias," she said, "Please don't clean this room, and leave the door closed." Why might the owner say this?

Accepted Answer

Poinsettias are short-day plants that require a long uninterrupted period of darkness to flower. Even a short flash of light at night could prevent flowering.

Question 13

Evolutionarily, floral parts represent modified

Accepted Answer

Floral parts such as petals, sepals, stamens, and carpels are considered to be modified leaves. This is supported by their development and structure, which are similar to leaves.

Question 14

A seed that lands in the forest soil is homozygous mutant for the CONSTANS (CO) gene, and as a result does not produce any functional CONSTANS protein.What do you predict will happen during the development of this seed?

Accepted Answer

The answer of A seed that lands in the forest...

Question 15

Competence means that a plant is _________, while determination means that a plant tissue __________.The acquisition of flowering competence is an example of a __________.

Accepted Answer

Competence refers to the ability to respond to signals that trigger a fate change, while determination refers to being committed to a specific developmental fate. The acquisition of flowering competence is an example of a phase change, which is the transition from one developmental stage to another. Therefore, the best choice is D, as it correctly defines competence and determination and provides an example of a phase change.

Question 16

Arabidopsis plants with a mutation in the gene embryonic Flower (EMF) produce flowers almost immediately after germination, before shoot growth occurs.What is the normal role of this gene?

Accepted Answer

The normal role of the EMF gene is to prevent flowering from happening too soon, allowing sufficient time for shoot growth and development. In the mutant plants with a mutation in EMF gene, this inhibitory function is disrupted, causing early flowering.

Question 17

Flowering can be regulated by light, temperature, gibberellin levels, or internal factors.What do all of these different flowering pathways have in common?

Accepted Answer

All four pathways ultimately result in an increase in the expression of the transcription factor LEAFY (LFY), which is a key regulator of flowering. LFY promotes the expression of genes involved in flower development and is necessary for the initiation of floral meristems. While CONSTANS (CO) is also involved in flowering, it is not an outcome common to all pathways.

Question 18

One way to improve crop productivity is to modify flowering time.This can allow for multiple growing seasons in one year, and can also increase grain production because a smaller plant has lower resource needs.You are approached by an agricultural company that wants to create an early-flowering transgenic plant.Using your knowledge of Arabidopsis genetics, which genetic modifications would you suggest?

Accepted Answer

In Arabidopsis, the embryonic flower (EMF) gene is a repressor of flowering, while the LEAFY (LFY) gene is a transcription factor that promotes flowering. Inhibiting EMF or overexpressing LFY would allow for early flowering and multiple growing seasons.

Question 19

A genus of primarily wind-pollinated plants includes one unusual species that has evolved to be pollinated by insects.Several morphological changes have accompanied this adaptation.The ______________ are more colorful, there is a nectary at the base of the ______________, the ________________ are shorter and produce sticky pollen, and the __________________ are stickier for enhanced pollen capture.

Accepted Answer

The petals are more colorful, there is a nectary at the base of the petals, the stamens are shorter and produce sticky pollen, and the sepals are stickier for enhanced pollen capture.

Question 20

A seed that lands in the forest soil is homozygous mutant for the LEAFY (LFY) gene, and as a result does not produce any functional LEAFY protein.What do you predict will happen during the development of this seed?

Accepted Answer

The LFY gene is a crucial gene for flower development. Without functional LFY protein, the plant cannot produce flowers. However, the plant can still germinate and grow vegetatively, producing leaves and stems. Therefore, choice A is the most likely outcome. Choice B is incorrect because the seed is still viable and able to germinate. Choice C is also incorrect because the plant needs time to develop before flowers can be produced. Choice D is partially correct, but the fact that the seed is homozygous mutant for the LFY gene means that it cannot produce flowers even if it is from a species regulated by the autonomous flowering pathway.

Quiz 41: Plant Reproduction