Question 1

The auxin produced in Arabidopsis embryos and Bicoid protein produced in Drosophila embryos have what similar function?

Accepted Answer

B

Question 2

The ABC genes in Arabidopsis are considered homeotic genes.What could be a reason for this classification?

Accepted Answer

Homeotic genes, like the ABC genes in Arabidopsis, code for regulatory transcription factors that control the development of specific structures, such as flower organs.

Question 3

The monopterous gene in Arabidopsis encodes a protein that is similar in its function to which animal protein?

Accepted Answer

Monopterous is involved in establishing the anterior-posterior axis in Arabidopsis embryos, similarly to how Bicoid establishes the anterior-posterior axis in fruit-fly embryos. Therefore, the function of Monopterous is similar to that of Bicoid.

Question 4

Plant and animal development share a number of features,but differ in major ways as well.Which of the following best summarizes the similarities between the two forms of development?

Accepted Answer

Both plants and animals require regulation of gene expression in order to properly develop and form different tissues and organs.

Question 5

Meristematic tissue cells in plants are most similar to which kind of cells in animals?

Accepted Answer

Meristematic tissue cells in plants are undifferentiated cells that have the ability to divide and differentiate into specialized cells. Similarly, embryonic stem cells in animals also have the ability to divide and differentiate into many different cell types. Both cell types have a high level of proliferation potential and the ability to differentiate into various cell types.

Question 6

Organs in developing flowers include all of the following except _____.

Accepted Answer

Whorls are not organs, but a term used to describe the arrangement of the floral organs. The other choices - sepals, petals, carpels, and stamens - are all actual organs of a flower.

Question 7

Interactions between proteins on the surface of the pollen grain and on the surface of the stigma are necessary for fertilization to proceed.What is the correct sequence of events that follow this interaction?

Accepted Answer

After the interaction, the pollen tube grows, sperm cells are formed and travel down the tube, and double fertilization occurs.

Question 8

In the early plant embryo,cells divide asymmetrically.Which structure does not result from divisions of the apical cell?

Accepted Answer

The suspensor is formed from the basal cell, not the apical cell, in the early plant embryo.

Question 9

Many flowering plant species have elaborate mechanisms to prevent an individual's pollen from fertilizing its own egg cells.Why?

Accepted Answer

Plants have evolved mechanisms to prevent inbreeding, which can lead to a decrease in genetic diversity and an increase in harmful recessive traits. By preventing self-fertilization, plants promote outcrossing and genetic variation within their populations.

Question 10

Plant embryos cannot undergo gastrulation.What ensures the correct positioning of cells during plant embryogenesis?

Accepted Answer

In plant embryogenesis, the correct positioning of cells is ensured by different cell sizes and planes of mitosis, which guide the spatial organization and differentiation of cells without the need for cell movement as in animal gastrulation.

Question 11

The floral meristem in flowering plants develops from the shoot apical meristem,which usually produces leaves.Which floral part is not a modified leaf?

Accepted Answer

The pollen tube is not a modified leaf, sepal, carpel, or petal. It is instead an extension of the male gametophyte and is responsible for delivering sperm to the female gametophyte during fertilization.

Question 12

In flowering plants,an event known as double fertilization occurs when _____.

Accepted Answer

Double fertilization is an event in flowering plants where two sperm cells enter the ovule. One sperm fertilizes the egg cell, forming the zygote, while the other sperm fertilizes a 2n cell known as the central cell or the primary endosperm cell. This fusion results in the formation of a 3n endosperm that acts as a nutrient source for the developing embryo. This unique process is essential for the successful reproduction of flowering plants. Option B and C are incorrect as they do not accurately describe double fertilization in flowering plants.

Question 13

Each of the following describes a similarity between yolk and endosperm except _____.

Accepted Answer

Yolk and endosperm are not both the result of a second fertilization process. Yolk is produced by cells in the ovary while endosperm is produced by cells in the fertilized ovule. A second fertilization process only occurs in plants, resulting in the production of endosperm, not in animals where yolk is produced.

Question 14

The basal cell in a plant embryo _____.

Accepted Answer

The basal cell in a plant embryo is the cell at the end of the zygote closest to the micropyle. It divides to form the suspensor, which anchors the embryo to the maternal tissue and helps transfer nutrients to the developing embryo.

Question 15

Auxin has an effect on plant embryos much like the Bicoid protein in Drosophila.If auxin were added to a culture of embryonic root cells,what would be the likely result?

Accepted Answer

Auxin promotes cell elongation and differentiation, so the addition of auxin to a culture of embryonic root cells would likely result in the root cells elongating and maturing. Choice B is incorrect because auxin would promote the differentiation of root cells into specific cell types, rather than causing them to revert to meristem cells. Choice C is incorrect because auxin promotes development, not halting it. Choice D is unlikely because root cells generally respond to auxin.

Question 16

What does the ABC model of flower development attempt to explain?

Accepted Answer

The ABC model of flower development attempts to explain how different combinations of gene products trigger the formation of different floral organs in whorls. It hypothesizes that three classes of genes (A, B, and C) interact to determine the identity of each whorl of floral organs.

Question 17

Plant embryos do not undergo the developmental processes of _____.

Accepted Answer

The answer of Plant embryos do not undergo the developmental...

Question 18

The ABC model of flower development suggests that genes A,B,and C _____.

Accepted Answer

The ABC model of flower development suggests that genes A, B, and C may work alone or together to form different flower organs and may transform one organ into another when inactivated. Therefore, option D is the correct answer. Option A is incorrect because each gene is not responsible for a single organ formation. Option B is partially correct but does not mention the possibility of organ transformation. Option C is incorrect because it implies that each gene can transform organs, which is not true. Option E is incorrect because it oversimplifies the role of each gene and does not mention the possibility of organ transformation.

Question 19

If the expression of the PHAN gene is blocked in plants,what will be the likely result?

Accepted Answer

The answer of If the expression of the PHAN gene...

Question 20

One unique feature of fertilization in flowering plants compared with animals is that _____.

Accepted Answer

Double fertilization is a unique feature of fertilization in flowering plants where two sperm cells are involved in the fertilization of one egg cell and one central cell, resulting in the formation of a zygote and endosperm, respectively. This process does not occur in animals.

Quiz 23: An Introduction to Plant Development