Question 1

The auxin produced in Arabidopsis embryos and Bicoid protein produced in Drosophila embryos have what similar function?
A)Both are regulatory transcription factors that serve as cell-to-cell signals.
B)Both are cytoplasmic determinants-they are loaded into eggs by cells in the mother or by female reproductive tissues.
C)Both trigger the transcription of homeotic loci-genes that specify the types of structures produced at a certain position.
D)Both establish a concentration gradient that demarcates the anterior-posterior axis.

Accepted Answer

Both auxin and Bicoid protein establish a concentration gradient that demarcates the anterior-posterior axis. Auxin is produced at the shoot apex and moves downward, creating a gradient. Bicoid protein is produced at the anterior end of the egg and diffuses toward the posterior end, creating a gradient. Both gradients are important for the proper development of the embryo.

Question 2

The ABC model of flower development suggests that
A)each of the three genes codes for the formation of a different flower organ.
B)genes may work alone or together to form different flower organs.
C)inactivation of genes may transform one organ into another.
D)both B and C are correct.
E)Answers A,B,and C are correct.

Accepted Answer

The ABC model proposes that three classes of genes (A, B, and C) work alone or in combination to determine the identity of the floral organs. Inactivation of these genes can lead to transformations of one organ type into another, supporting both B and C.

Question 3

In flowering plants,an event known as double fertilization occurs when
A)two sperm enter the ovule;one fertilizes the egg,and the other fertilizes a 2n cell to generate endosperm.
B)two sperm cells fertilize one normal egg cell to make a 3n embryo,and the embryo later becomes 2n during a unique mitotic division.
C)two eggs are simultaneously fertilized by two sperm nuclei.
D)None of the above apply.

Accepted Answer

In double fertilization of flowering plants, two sperm cells enter the ovule. One sperm fertilizes the egg cell to form a zygote, which gives rise to the embryo. The other sperm fertilizes a 2n cell, known as the central cell, to form the endosperm, which serves as a source of nutrients for the developing embryo. This unique process is one of the defining characteristics of angiosperms. Option B is incorrect, as there is no such thing as a 3n embryo in flowering plants. Option C is also incorrect, as only one egg cell is fertilized by one sperm cell.

Question 4

Plant embryos cannot undergo gastrulation.What ensures the correct positioning of cells during plant embryogenesis?
A)cell movements inside the seed coat
B)genetic differences among the cells
C)cytoplasmic determinants in the cells
D)different cell sizes and planes of mitosis
E)expansion of the cotyledons

Accepted Answer

The answer of Plant embryos cannot undergo gastrulation.What ensures the...

Question 5

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 is the likely result?
A)Root cells would elongate and mature.
B)Root cells would change into meristem cells.
C)Root cells would halt their development.
D)Root cells would not respond to auxin.

Accepted Answer

Auxin promotes cell elongation and differentiation, which would result in the embryonic root cells maturing and elongating.

Question 6

Many flowering plant species have elaborate mechanisms to prevent an individual's pollen from fertilizing its own egg cells.Why?
A)to prevent inbreeding
B)to prevent polyspermy
C)to prevent cross-species fertilization and the production of dysfunctional hybrid offspring
D)to prevent double fertilization and the formation of endosperm

Accepted Answer

Preventing inbreeding helps to maintain genetic diversity within a population, which can increase the species' overall fitness and adaptability.

Question 7

The monopterous gene in Arabidopsis encodes a protein that is similar in its function to which animal protein?
A)MyoD in frog embryos
B)Bicoid in fruit-fly embryos
C)keratin in human embryos

Accepted Answer

The monopterous gene in Arabidopsis encodes a protein that functions in embryonic patterning, specifically in the formation of the shoot meristem. This protein is similar in its function to Bicoid, a protein in fruit-fly embryos that helps to establish the anterior-posterior axis of the embryo. MyoD is a transcription factor that functions in muscle development in frog embryos, while keratin is a structural protein found in hair, skin, and nails in human embryos.

Question 8

In the early plant embryo,cells divide asymmetrically.Which structure does NOT result from divisions of the apical cell?
A)the suspensor
B)the cotyledons
C)the hypocotyls
D)the shoot

Accepted Answer

The suspensor is formed from the basal cell, not the apical cell, in the early plant embryo. The apical cell gives rise to the cotyledons, hypocotyl, and shoot.

Question 9

The ABC genes in Arabidopsis are considered homeotic genes.What could be a reason for this classification?
A)Each of the three genes codes for a different flower organ.
B)Each gene codes for regulatory transcription factors.
C)Each gene is similar in sequence to homeotic genes in Drosophila.
D)Each gene codes for proteins similar to Hox genes in mice.
E)Each gene directs different kinds of morphogenesis.

Accepted Answer

The answer of The ABC genes in Arabidopsis are considered...

Question 10

If the expression of the PHAN gene is blocked in plants,what will be the likely result?
A)Plants will fail to develop leaves.
B)Plants will develop more leaves than usual.
C)Plants will develop leaves in very simple shapes.
D)Plants will develop leaves in inappropriate places.

Accepted Answer

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

Question 11

The basal cell in a plant embryo
A)develops from the root of the embryo.
B)forms the suspensor that anchors the embryo.
C)differentiates after gastrulation.
D)divides to form cotyledons.
E)divides to form hypocotyls.

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 12

Of the following developmental processes,which is not undergone by plant embryos?
A)fertilization
B)cleavage
C)embryogenesis
D)gastrulation
E)organogenesis

Accepted Answer

Gastrulation is a process specific to animal development, not plant embryos.

Question 13

What does the ABC model of flower development attempt to explain?
A)how different combinations of gene products trigger the formation of different floral organs
B)why petals are found on the inside of the whorl of sepals instead of on the outside
C)why the four types of floral organs occur in whorls
D)why apical meristems are converted to floral meristems in response to specific cell-to-cell signals

Accepted Answer

The ABC model of flower development attempts to explain how different combinations of gene products trigger the formation of different floral organs by specifying the identity of each of the four types of floral organs (sepals, petals, stamens, and carpels).

Question 14

One unique feature of fertilization in flowering plants compared with animals is that
A)plant sperm are motile.
B)multiple ovules exist in the ovary.
C)the process involves double fertilization.
D)nuclear fusion does not take place.
E)the gametes are diploid,not haploid.

Accepted Answer

Flowering plants have a unique process of double fertilization, which involves the fusion of one sperm with the egg cell to form a zygote and the fusion of another sperm with the two polar nuclei to form the endosperm. This process ensures successful seed development and is not present in animal fertilization. A is incorrect because plant sperm are indeed motile. B is incorrect because although multiple ovules may exist in the ovary, it is not a unique feature compared to animal fertilization. D is incorrect because nuclear fusion does take place in both animal and plant fertilization. E is incorrect because gametes are always haploid in both animals and plants.

Question 15

Meristematic tissue cells in plants are MOST similar to which kind of cells in animals?
A)somite cells
B)ectodermal cells
C)embryonic stem cells
D)mesodermal cells

Accepted Answer

Meristematic cells are undifferentiated cells that have the ability to divide and differentiate into different cell types. Similarly, embryonic stem cells in animals are also undifferentiated cells that have the potential to become any cell type in the body. Therefore, meristematic tissue cells in plants are most similar to embryonic stem cells in animals.

Question 16

The floral meristem in flowering plants develops from the shoot apical meristem,which usually produces leaves.Which floral part is not a modified leaf?
A)sepal
B)carpel
C)stamen
D)receptacle
E)petal

Accepted Answer

The receptacle is not a modified leaf. It is the base of the flower to which all other floral parts are attached.

Question 17

Yolk and endosperm share a number of functions.Which of the following does NOT describe a similarity between them?
A)Yolk and endosperm both provide nutrition for embryos.
B)Yolk and endosperm both contain proteins.
C)Yolk and endosperm are both the result of a second fertilization process.
D)Yolk and endosperm are both cellular products.

Accepted Answer

This statement is incorrect. Yolk is a part of the egg cell and is present before fertilization, while the endosperm is a product of fertilization in plants. Therefore, they are not the result of the same process. The other options are correct similarities between yolk and endosperm.

Question 18

Organs in developing flowers include all of the following EXCEPT
A)whorls.
B)sepals.
C)petals.
D)carpels.
E)stamens.

Accepted Answer

Whorls are not organs but rather a term used to describe the arrangement of the different types of organs (sepals, petals, stamens, and carpels) in a flower. Therefore, all of the choices listed are organs found in developing flowers except for whorls.

Question 19

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?
A)growth of pollen tube,double fertilization,formation of sperm
B)formation of sperm,growth of pollen tube,double fertilization
C)double fertilization,growth of pollen tube,formation of sperm
D)formation of sperm,double fertilization,growth of pollen tube
E)growth of pollen tube,formation of sperm,double fertilization

Accepted Answer

The answer of Interactions between proteins on the surface of...

Question 20

All of the following statements are true of the endosperm except that
A)it may be likened to the yolk of an animal egg.
B)it is a triploid tissue.
C)it is used as a food source by the embryo.
D)it is formed from equal contributions of both parents.
E)it is the major energy source for germination.

Accepted Answer

The endosperm is not formed from equal contributions of both parents, but rather from the fusion of a haploid sperm cell and two haploid polar nuclei from the mother plant. This makes it triploid, containing three sets of chromosomes instead of the usual two.

Quiz 23: An Introduction to Plant Development

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

The ABC model of flower development suggests that

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

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

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 is the likely result?

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

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

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

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

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

The basal cell in a plant embryo

Of the following developmental processes,which is not undergone by plant embryos?

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

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

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

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

Yolk and endosperm share a number of functions.Which of the following does NOT describe a similarity between them?

Organs in developing flowers include all of the following EXCEPT

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?

All of the following statements are true of the endosperm except that