Question 1

What is the similarity between spores and gametes?

Accepted Answer

Both spores and gametes are haploid, meaning they contain a single set of chromosomes.

Question 2

If an ovary contains 50 ovules,what is the minimum number of pollen grains that must land in order to form 50 mature seeds?

Accepted Answer

Each ovule requires one pollen grain to form a mature seed.

Question 3

How are the life cycles of liverworts and angiosperms alike?

Accepted Answer

Both liverworts and angiosperms have a sporophyte stage that produces spores. While the dominant generation is different in the two groups (gametophyte is dominant in liverworts, and sporophyte is dominant in angiosperms), the production of spores by the sporophyte is a shared feature.

Question 4

The flowering hormone is made in _____ and alters development of _____.

Accepted Answer

The flowering hormone, known as florigen, is produced in the leaves and it travels to the apical meristem to induce flowering.

Question 5

A gardener in Canada wants to surprise his mother on her birthday and make her favorite Shrubalthea bush flower in May instead of the end of June.The bush is growing in the greenhouse.Which of the following might make the Shrubalthea bush flower early?

Accepted Answer

Shrubalthea is a short-day plant, which means that it flowers in response to short nights. Grafting leaves of a Shrubalthea that was exposed to short nights will cause the bush to flower early because the leaves will produce a hormone that triggers flowering.

Question 6

Pollen from a plant with the S₁S₂ genotype is recognized and allowed to germinate on the stigma of the same plant with the S₁S₂ genotype.According to the S-system hypothesis,this indicates that the plant is _____.

Accepted Answer

The S-system hypothesis states that self-incompatibility occurs when the S-genes (involved in determining pollen compatibility) in the pollen and stigma match. In this case, the pollen and stigma have the same genotype (S₁S₂), indicating that the plant is self-compatible and can self-pollinate.

Question 7

What is an essential part of alternation of generations in plants?

Accepted Answer

In alternation of generations, gametes are produced by mitosis in the gametophyte stage, not meiosis. Meiosis produces spores, which develop into the gametophyte.

Question 8

During self-fertilization,which of the following is absent?

Accepted Answer

In self-fertilization, pollen is transferred within the same flower or between flowers of the same plant, so transfer of pollen from one plant to another is absent.

Question 9

What is not true about the carpel of a flower?

Accepted Answer

Meiosis of the megaspore actually forms four haploid cells, one of which develops into the embryo sac containing eight nuclei.

Question 10

It is estimated that animal- or insect-pollinated plants produce 1000 pollen grains for each ovule;wind-pollinated plants produce 1,000,000 pollen grains for each ovule.What does that indicate about pollination systems?

Accepted Answer

Wind-pollinated plants produce a much higher number of pollen grains for each ovule compared to animal or insect-pollinated plants. This high quantity is required because the chance of successful pollination is much lower in the case of wind pollination, as the pollen has to travel much longer distances in the wind to reach the female reproductive structures. This indicates that wind pollination is less efficient than animal-assisted pollination.

Question 11

A summer occupation in the Corn Belt states is de-tasseling the corn:
Removing unwanted male flowers so that female flowers on the same plant are pollinated by the desired pollen for the hybrid corn.What does this tell you about corn?

Accepted Answer

Corn has separate male and female flowers on the same plant, making the flowers imperfect and the plant monoecious. De-tasseling involves removing the male flowers (tassels) to control pollination.

Question 12

While looking at a flower in your garden,you notice that it has carpels with very long styles and stamens with very short filaments.This plant most likely to reproduce by _____.

Accepted Answer

The long styles on the carpels suggest that the plant is adapted to receiving pollen from other plants. The short filaments on the stamens suggest that the plant may be less effective at self-pollination, as the pollen may not be able to successfully reach the carpels. Therefore, the most likely method of reproduction for this plant is cross-pollination, where pollen from a different plant is transferred to the carpels of this plant.

Question 13

Plants in crop fields such as corn are genetically very similar.What are benefits of this phenomenon? What are pitfalls of this phenomenon?

Accepted Answer

The answer of Plants in crop fields such as corn...

Question 14

Cottonwood,aspen,and willow trees have beige flowers,with no petals,that appear before the tree's leaves are out in the spring;and they are dioecious.What does that indicate about these trees?

Accepted Answer

Dioecious plants have male and female reproductive structures on separate plants, which means they rely on external agents like wind for pollination rather than self-pollination. The lack of petals and early flowering also suggest wind pollination.

Question 15

What is the male gametophyte made of?

Accepted Answer

The male gametophyte, also known as the pollen grain, is made up of a generative cell and a tube cell. The generative cell divides to produce two sperm cells which are responsible for fertilization, while the tube cell produces the pollen tube that allows the sperm cells to reach and fertilize the egg cell. Therefore, the correct answer is option D - generative cell and tube cell.

Question 16

Plants produce more seeds when they reproduce asexually than sexually.Yet most plants reproduce sexually in nature.What is the probable explanation for the prevalence of sexual reproduction?

Accepted Answer

Sexual reproduction allows for the shuffling and recombination of alleles, leading to greater genetic diversity within a population. This is advantageous for adaptation to changing environmental conditions and for avoiding accumulation of harmful mutations. Asexual reproduction, on the other hand, produces offspring that are genetically identical to the parent and may not have the same level of adaptability. While asexual reproduction may produce more offspring, sexual reproduction provides the potential for greater genetic variation and thus a greater chance of survival and success for a species in the long run.

Question 17

Which of the following correctly identifies the function of the flower part named?

Accepted Answer

Sepals protect the flower bud. Petals attract pollinators, not seed-dispersing animals. The stigma is part of the female reproductive organ and does not produce nectar. The carpel is the female reproductive part and does not produce pollen; the stamen does.

Question 18

Home flower gardeners in northern latitudes like to grow plants that flower only in the spring or flower only in the late summer and fall.They are planting flowers that are most sensitive to _____.

Accepted Answer

Plants that flower in response to night length are called "short-day" or "long-night" plants. They require a certain amount of uninterrupted darkness in order to begin their flowering process. Therefore, home gardeners in northern latitudes prefer to grow these types of plants in the fall when the nights are long, as this prompts them to flower. In contrast, "long-day" or "short-night" plants require shorter periods of darkness and therefore are most sensitive to phototropins, which regulate the response of plants to light. Temperature differences, water and nutrient availability can also influence plant growth and flowering, but they are not the most important factors for determining when a plant flowers in northern latitudes.

Question 19

A population of flowers varies from deep blue to nearly white.Bees are active during the day and prefer color.Moths are active at night,when colors are not very visible and white is more conspicuous.Design a scenario in which the blue and white flowers form two species where there once was one species.You must end with a conclusion that the two new species cannot interbreed (a definition of a species).

Accepted Answer

The answer of A population of flowers varies from deep...

Question 20

The sperm and egg each contribute 50% of the nuclear genetic material to the zygote that becomes the embryo and the new plant.Mitochondria and plastids that become chloroplasts are passed primarily from the female parent.What feature of the male or female gametophytes accounts for this?

Accepted Answer

The female gametophyte is larger and formed from one surviving megaspore. This allows for the accumulation of more cytoplasmic organelles, such as mitochondria and plastids, which are primarily passed down from the female parent to the zygote that becomes the embryo and the new plant. The male gametophyte, on the other hand, is small and formed in the anthers.

Quiz 40: Plant Reproduction