Deck 23: An Introduction to Plant Development

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.

Answer 1

B

Question 2

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.

Answer 2

B

Question 3

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

Answer 3

B

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?

A)Both plants and animals develop from a process of single fertilization.
B)Both plants and animals produce specialized tissues through irreversible processes of determination and differentiation.
C)Both plants and animals produce gametes via meiosis followed by mitosis of haploid cells.
D)Both plant and animal development depend on precise control of gene expression in time and in space.

Question 5

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

Question 6

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

A)whorls
B)sepals
C)petals
D)carpels
E)stamens

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?

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

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

Question 9

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

Question 10

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

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?

A)sepal
B)carpel
C)stamen
D)pollen tube
E)petal

Question 12

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.

Question 13

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

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

Question 14

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

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?

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.

Question 16

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

Question 17

Plant embryos do not undergo the developmental processes of _____.

A)fertilization
B)cleavage
C)embryogenesis
D)gastrulation
E)organogenesis

Question 18

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

A)each code for the formation of a different flower organ
B)may work alone or together to form different flower organs
C)may transform one organ into another when inactivated
D)may work alone or together to form different flower organs and may transform one organ into another when inactivated
E)Each of the three genes codes for the formation of a different flower organ and may transform one organ into another when inactivated.

Question 19

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.

Question 20

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

Question 21

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

A)Animal tissues are irreversibly differentiated;plant tissues retain plasticity throughout life.
B)Animal cells frequently undergo programmed cell death;plant cells do not.
C)Animal development is controlled by regulatory gene sets such as Hox genes;plants have no similar control systems.
D)Animal gametes are produced only after maturity is reached;plant gametes can be produced throughout a plant's lifetime.