Deck 19: Differential Gene Expression in Development

Question 1

A structure that enables an embryo to feed directly from its mother is called a

A) zygote.
B) seed.
C) stem cell.
D) placenta.
E) morphogen.

Answer 1

D

Question 2

Cloning experiments on sheep, frogs, and mice have shown that

A) nuclei of adult cells are totipotent.
B) nuclei of embryonic cells can be totipotent.
C) nuclei of differentiated cells have different genes than zygote nuclei have.
D) differentiation is fully reversible in all cells of a frog.
E) differentiation involves permanent changes in the genome.

Answer 2

B

Question 3

Which statement about the homeobox is not true?

A) It is transcribed and translated.
B) It is found only in animals.
C) Proteins containing the homeodomain bind to DNA.
D) It is a sequence of DNA shared by more than one gene.
E) It occurs in Hox genes.

Answer 3

B

Question 4

Stem cells from adult animals

A) are always totipotent.
B) divide when provided with external signals.
C) are not present in bone marrow.
D) are present in an embryo but not an adult.
E) can be turned into differentiated cells with only a few genes.

Question 5

Which of the following statements is false?

A) The fate of a cell can be determined by morphogenesis.
B) Differential gene expression plays an important role in determining cell fate.
C) Throughout development, especially in animals, the range of possible cell fates becomes progressively more restricted.
D) The developmental potential of early embryonic cells is greater than their actual fates.
E) All of the above are true; none is false.

Question 6

Which of the following statements is true?

A) Apoptosis is important only in animal development.
B) Apoptosis is important only in plant development.
C) In plant development, cells are constrained by cell walls and normally do not move.
D) In plant development, cell expansion is often slow to begin.
E) Both a and c

Question 7

Which of the following properties is required for an organism to undergo development?

A) It must be diploid during some part of its life cycle.
B) It must be multicellular during some part of its life cycle.
C) The embryo must be contained within a protective structure during some part of its life cycle.
D) All of the above
E) None of the above

Question 8

Which of the following techniques or studies would be most useful in testing the hypothesis that "The fate of the cells in an early fish embryo is irrevocably determined"?

A) Monitoring gene expression in the cells and looking for differences in cells in different regions
B) Transplanting cells from one region to another
C) Examining structural differences among cells in different regions by means of a light microscope
D) Using nuclear transfer procedures
E) Observing whether the cells are undergoing apoptosis

Question 9

Homeotic mutations

A) are often severe and result in structures at inappropriate places.
B) cause subtle changes in the forms of larvae or adults.
C) occur only in prokaryotes.
D) do not affect the animal's DNA.
E) are confined to the zone of polarizing activity.

Question 10

Differentiated cells in the process of forming the liver of a mouse provide an example of

A) differentiation.
B) determination.
C) apoptosis.
D) induction.
E) morphogenesis.

Question 11

In the process of pattern formation in the Drosophila embryo,

A) the first steps are specified by Hox genes.
B) mutations in pair rule genes result in embryos missing every other segment.
C) mutations in gap genes result in the insertion of extra segments.
D) segment polarity genes determine the dorsal-ventral axes of segments.
E) all segments develop the same organs.

Question 12

Which of the following statements about developmental processes is true?

A) Biologists usually can observe determination via microscopic studies.
B) Differentiation is usually followed by determination.
C) Differentiation consists of the actual biochemical, structural, and functional changes of a cell.
D) All of the above
E) None of the above

Question 13

The term "induction" describes a process in which a cell or cells

A) influence the development of another group of cells.
B) trigger cell movements in an embryo.
C) stimulate the transcription of their own genes.
D) organize the egg cytoplasm before fertilization.
E) inhibit the movement of the embryo.

Question 14

Which statement about cytoplasmic determinants in Drosophila is not true?

A) They specify the dorsal-ventral and anterior-posterior axes of the embryo.
B) Their positions in the embryo are determined by cytoskeletal action.
C) Some are products of specific genes in the mother fruit fly.
D) They do not produce gradients.
E) They have been studied by the transfer of cytoplasm from egg to egg.

Question 15

Which of the following statements about stem cell treatments is false?

A) Until about 1990, no stem cell treatments were available for humans.
B) Stem cells can be gathered from adipose (fatty) tissue.
C) Stem cells are always in the process of actively dividing.
D) Connective tissue often arises from mesenchymal stem cells.
E) All of the above are true; none is false.

Question 16

The process by which the developmental fate of a cell is set is called

A) determination.
B) morphogenesis.
C) differentiation.
D) induction.
E) totipotency.

Question 17

Which statement about determination is true?

A) Differentiation precedes determination.
B) All cells are determined after two cell divisions in most organisms.
C) A determined cell will keep its determination no matter where it is placed in an embryo.
D) A cell changes its appearance when it becomes determined.
E) A differentiated cell has the same pattern of transcription as a determined cell.

Question 18

Which of the following statements about the processes of development is true?

A) Morphogenesis requires prior differentiation.
B) Determination requires prior differentiation.
C) Differentiation requires prior determination.
D) Both a and c
E) None of the above

Question 19

Which statement about induction is not true?

A) One group of cells induces adjacent cells to develop in a certain way.
B) It triggers a sequence of gene expression in target cells.
C) Single cells cannot form an inducer.
D) A tissue may be induced as well as make an inducer.
E) The chemical identification of specific inducers has not been achieved.

Question 20

In fruit flies, the following genes are used to determine segment polarity: (k) gap genes; (l) Hox genes; (m) maternal effect genes; (n) pair rule genes. In what order are these genes expressed during development?

A) k, l, m, n
B) l, k, n, m
C) m, k, n, l
D) n, k, m, l
E) n, m, k, l

Question 21

Which of the following statements about stem cells is true?

A) Embryonic stem cells can be harvested from human embryos produced during in vitro fertilization.
B) The only known pluripotent animal stem cells are derived from embryos.
C) The manner in which embryonic stem cells differentiate can be channeled by the appropriate signals.
D) Both a and b
E) Both a and c

Question 22

Which of the following statements about cloned animals is true?

A) Cloned pets will have the same behavioral characteristics as the original pet.
B) Cloning has been used to preserve endangered species.
C) Cloning has been used in conjunction with recombinant DNA technology for commercial purposes.
D) Both a and b
E) Both b and c

Question 23

If a cell that has been isolated from the root of a carrot is given the appropriate nutrients and cues, it will give rise to a mass of undifferentiated cells. This new structure is called

A) a clone.
B) a ewe.
C) a callus.
D) the lens placode.
E) None of the above

Question 24

Of the following techniques used in the cloning of Dolly the sheep, which one was initially used by Briggs and King in their studies with frog embryos?

A) Transferring cells from one location to another on the embryo
B) Enucleating an egg
C) Arresting the cell cycle of the donor cells
D) Bisecting the embryo
E) None of the above

Question 25

The difference between the top and the bottom in a developing organism is called

A) pluripotency.
B) determination.
C) pattern formation.
D) polarity.
E) None of the above

Question 26

Which of the following statements about hematopoietic stem cell transplantation is false?

A) It involves pluripotent stem cells.
B) It uses the patient's own stem cells.
C) It is used because some treatments against cancer also kill hematopoietic cells.
D) It leads to the production of both red and white blood cells.
E) All of the above are true; none is false.

Question 27

The process of cytoplasmic segregation would be a partial answer to which of the following questions?

A) How can one reset a differentiated cell such that it can produce many different cell types?
B) How can so many different cell types come from the egg, a single cell?
C) What roles do transcription factors play in controlling cell differentiation?
D) What new technique was used by Yamanaka and his colleagues to obtain induced pluripotent stem cells?
E) What new technique was used in the cloning of Dolly the sheep?

Question 28

In the first successful cloning of a sheep, cells from the ewe's udder were modified to become appropriate donor cells. In order for these udder cells to be suitable donor cells, they were

A) arrested in the G1 phase of the cell cycle.
B) arrested in the G2 phase of the cell cycle.
C) supplied with extra nutrients.
D) Both a and c
E) Both b and c

Question 29

During the 1950s, Robert Briggs and Thomas King performed pioneering studies of development using nuclear transfer of frog embryos. Which of the following was not one of the conclusions that could be drawn from their studies?

A) The nuclei of early frog embryos retain the genetic potential for totipotency.
B) The cytoplasmic environment around a nucleus can modify its fate.
C) Information is lost from the nuclei of cells during the early stages of development.
D) There is a principle of genomic equivalence.
E) All of the above were conclusions of the studies.

Question 30

Which of the following is a technique that can be used to show genomic equivalence?

A) RNAi
B) Nucleic acid hybridization
C) Induction
D) Two-dimensional gel electrophoresis
E) RFLP mapping

Question 31

Which of the following is the correct ranking of stem cells with respect to the number of cell types into which they can differentiate (from greatest to least)?

A) Multipotent > pluripotent > totipotent
B) Pluripotent > totipotent > multipotent
C) Pluripotent > multipotent > totipotent
D) Totipotent > pluripotent > multipotent
E) Totipotent > multipotent > pluripotent

Question 32

In laboratory mice, embryonic stem cells can be removed from early embryos called

A) gastrulas.
B) blastocysts.
C) pluteus embryos.
D) "heart" embryos.
E) None of the above

Question 33

Adult stem cells can be best described as

A) homeotic.
B) totipotent.
C) pluripotent.
D) multipotent.
E) morphogenic.

Question 34

The first known successful cloning of a mammal was accomplished by

A) Dolly Madison.
B) Robert Briggs and Thomas King.
C) Eric Davidson.
D) Ed Lewis.
E) Ian Wilmut.

Question 35

The fact that animal somatic cells from early embryos retain their totipotency was first demonstrated by

A) Ed Lewis.
B) James Watson and Francis Crick.
C) Robert Briggs and Thomas King.
D) Eric Davidson and Greg Wray.
E) Ian Wilmut.

Question 36

What do we call a cell that is able to give rise to every cell in the adult body?

A) Determined
B) Pluripotent
C) Totipotent
D) Multipotent
E) Morphogenic

Question 37

Which of the following statements about the gene MyoD is true?

A) It acts as a transcription factor.
B) It is involved in the differentiation of plant cells.
C) It is activated in stem cells present in adult muscle tissue.
D) Both a and b
E) Both a and c

Question 38

An increase in the concentration of MyoD would most likely lead to a(n) _______ of p21 expression, which would _______ the activity of cyclin-dependent kinases.

A) increase; increase
B) increase; decrease
C) decrease; increase
D) decrease; have no effect on
E) decrease; decrease

Question 39

The "top" (or "north") pole of a developing embryo is often referred to as the _______ pole; the "bottom" (or "south") pole is the _______ pole.

A) dorsal; animal
B) dorsal; vegetal
C) animal; dorsal
D) animal; ventral
E) animal; vegetal

Question 40

The gene chips used in the techniques developed by Yamanaka and colleagues for induced pluripotent stem cells

A) reveal DNA sequence variants that differ between embryonic stem cells and nonstem cells.
B) reveal DNA sequence variants that differ between hematopoietic stem cells and nonstem cells.
C) reveal gene expression differences between embryonic stem cells and nonstem cells.
D) reveal gene expression differences between hematopoietic stem cells and nonstem cells.
E) induce gene expression in stem cells.

Question 41

If the anchor cell is destroyed in Caenorhabditis elegans,

A) no vulva will form.
B) no anchorettes will form.
C) secondary vulval precursors will become primary vulval cells.
D) another cell will differentiate into an anchor cell.
E) signals from the nematode's surface will direct readjustments.

Question 42

If an eight-cell sea urchin embryo is bisected horizontally,

A) both halves develop into normal, but small, larvae.
B) the top cells remain embryonic, while the bottom cells produce an abnormal larva.
C) the top cells remain embryonic, while the bottom cells produce a small, but normal, larva.
D) the bottom cells remain embryonic, while the top cells produce an abnormal larva.
E) the bottom cells remain embryonic, while the top cells produce a small, but normal, larva.

Question 43

In a hypothetical developmental biology experiment, the researchers place a barrier between the alpha ludens (a made-up structure) and tissues that are supposed to develop into the beta ludens. If the beta ludens _______, then signals from the alpha ludens are acting as _______ of the beta ludens.

A) develops; inducers
B) does not develop; inducers
C) develops; transcription factors
D) does not develop; transcription factors
E) develops; morphogens

Question 44

Which of the following statements about pattern formation is false?

A) It is linked to morphogenesis.
B) It involves cell division.
C) It involves differentiation.
D) It involves programmed cell death.
E) All of the above are true; none is false.

Question 45

If the MADS box genes in class A and class B are both expressed in the normal development of Arabidopsis, _______ will be produced.

A) carpels
B) petals
C) stamens
D) sepals
E) None of the above

Question 46

Which of following statements about the cytoskeleton and its role in development is false?

A) Its microtubules, which move material throughout the cell, have built-in polarity.
B) It contributes to the asymmetric distribution of cytoplasmic determinants in the egg.
C) Specific proteins can bind to elements on the cytoskeleton.
D) It acts as an inducer.
E) All of the above are true; none is false.

Question 47

The differentiation of whorls in Arabidopsis thaliana is regulated by _______ genes.

A) organ identity
B) dimer
C) whorl locator
D) caspases
E) central axis control

Question 48

The process by which signaling molecules from one tissue (or group of cells) affect the development of adjacent tissue is called

A) determination.
B) morphogenesis.
C) placode.
D) differentiation.
E) induction.

Question 49

The process that results in spatial organization of an organism or a tissue is called

A) induction.
B) differentiation.
C) apoptosis.
D) determination.
E) pattern formation.

Question 50

Which of the following statements about apoptosis is true?

A) It is an important process in the development of human fingers and toes.
B) Despite more than 600 million years of evolutionary divergence, humans and nematodes share similar apoptosis pathways.
C) Only a few neurons die as a result of programmed cell death in normal brain development in humans.
D) Both a and b
E) Both b and c

Question 51

The primary inducer of the vulva in C. elegans comes from the _______ cell.

A) primary vulval precursor
B) lens placode
C) homeotic
D) anchor
E) None of the above

Question 52

Development of the lens in the vertebrate eye is induced by signals from the

A) cornea.
B) optic vesicle.
C) vulva.
D) mesoderm.
E) lens placode.

Question 53

In the normal course of development in Arabidopsis, a particular group of cells should develop into carpel tissue. If MADS box B gene were improperly expressed in those cells, they would develop into _______ tissue.

A) carpel
B) petal
C) stamen
D) sepal
E) Both b and c

Question 54

In normal development of Arabidopsis, stamens develop from

A) whorl 1.
B) whorl 2.
C) whorl 3.
D) whorl 4.
E) None of the above

Question 55

If the protein Bcl-2 is improperly overexpressed in a developing human embryo the most likely outcome will be

A) webbed hands and feet.
B) abnormal brain development due to too few cells.
C) abnormal brain development due to too many of the wrong cells.
D) sickle cell anemia.
E) Down syndrome.

Question 56

Yolk molecules tend to accumulate in the vegetal half in the fertilized eggs of most animals, and the presence of yolk can slow down cell division. Based on this observation, which of the following statements is most likely to be true?

A) Assuming that there has been no movement, cells in the vegetal half of the embryo should be larger than those in the animal half.
B) Assuming that there has been no movement, cells in the vegetal half of the embryo should be smaller than those in the animal half.
C) Polarity exists in the fertilized egg.
D) Both a and c
E) Both b and c

Question 57

If one were to block expression of the LIN-3 gene in the early development of C. elegans, which of the following would be the most likely result?

A) Cells that would normally differentiate into the optic vesicles would remain epidermis.
B) More cells than normal would differentiate into the optic vesicles.
C) More cells would become anchor cells.
D) Cells that would normally differentiate into vulval precursors would become epidermis.
E) Cells that would normally differentiate into epi­dermis would become vulval precursors.

Question 58

In normal development of Arabidopsis, whorl 1 produces

A) carpels.
B) petals.
C) stamens.
D) sepals.
E) None of the above

Question 59

Which of the following cells differentiates into the primary vulval precursor cell in C. elegans development?

A) The anchor cell
B) The cell closest to the anchor cell
C) The lens placode cell
D) The caspase cell
E) The ced-4 cell

Question 60

Different results are achieved when an eight-cell sea urchin embryo is bisected horizontally as opposed to when it is bisected vertically. This observation supports which of the following statements?

A) Cellular determinants are equally distributed in the embryo.
B) Differentiation has occurred by the eight-cell stage.
C) Inducers have determined cell fate.
D) Polarity exists in the embryo by the eight-cell stage.
E) None of the above

Question 61

Which of the following statements about Hox genes is false?

A) They contain homeoboxes.
B) They were derived from duplications of a single ancestral gene.
C) They encode transcription factors.
D) They are found only in Drosophila and a few closely related genera of flies.
E) All of the above are true; none is false.

Question 62

Mutations in the disheveled gene in Drosophila can lead to various defects in the hairs of the thorax of adult flies, along with misshapen wings. These morpho­logical abnormalities arise because of improper determination of the boundaries of individual seg­ments during the fly's early development. Based on this information, disheveled is most likely a _______ gene.

A) maternal effect
B) gap
C) pair rule
D) segment polarity
E) Hox

Question 63

The process of _______ leads to cells with specific structures and functions.

Question 64

Suppose you were in a laboratory engaged in genetically modifying a plant to increase the size of its fruit (its carpels). Assuming that MADS box genes play the same floral organ-identity roles in this plant that they do in Arabidopsis, _______ the domain of expression of gene _______ would most likely yield an increase in fruit size.

A) increasing; A
B) decreasing; A
C) increasing; B
D) decreasing; B
E) decreasing; C

Question 65

Which of the following distinguishes the developmental cascade seen in Drosophila melanogaster from a signal transduction cascade?

A) Transcription factors are involved only in the signal transduction cascade.
B) Transcription factors are involved only in the developmental cascade.
C) The signal transduction cascade occurs mainly within a single cell.
D) The signal transduction cascade takes place over a much longer period of time.
E) Protein kinases are found only in the signal transduction cascade.

Question 66

For which of the following classes of developmental genes is the phenotype of the developing individual not determined by the individual's genotype?

A) Gap genes
B) Pair rule genes
C) Maternal effect genes
D) Hox genes
E) MADS box genes

Question 67

Who discovered that Antennapedia and bithorax mutations are the result of changes in Hox genes?

A) Stephen Jay Gould
B) David Hofmans
C) Hans Driech
D) Ian Wilmut
E) Edward Lewis

Question 68

Female Drosophila that are homozygous for the bicoid maternal effect gene mutation produce larvae with no head or thorax. When cytoplasm from the anterior end of a wild-type egg is inoculated into the anterior end of a bicoid mutant egg, the treated egg develops normally. What causes the restoration of normal development in the mutant eggs?

A) Disruption of mutant bicoid gene expression after their inoculation with wild-type egg cytoplasm
B) Normal bicoid gene expression
C) Expression of the nanos gene
D) Induction of normal development by adjacent embryo cells
E) The inoculation of normal egg cytoplasm

Question 69

Which of the following would most likely lead to the development of two heads in a Drosophila embryo, one at each end?

A) Injecting Nanos protein into the posterior region of the egg
B) Knocking out the expression of the bicoid gene in the anterior region of the egg
C) Knocking out the expression of the bicoid gene in the posterior region of the egg
D) Injecting the posterior region of the egg with cytoplasm from the anterior region of another wild-type egg.
E) injecting the anterior region of the egg with cytoplasm from the posterior region of another wild-type egg.

Question 70

Which of the following is a Drosophila maternal effect gene?

A) Hunchback
B) Bicoid
C) Antennapedia
D) Bithorax
E) Shh

Question 71

Which of the following classes of pattern formation genes is responsible for organizing broad areas along the anterior-posterior axis?

A) Maternal effect genes
B) Gap genes
C) Pair rule genes
D) Segment polarity genes
E) Hox genes

Question 72

Mutations in genes of the _______ gene class often result in the omission of several contiguous larval segments in flies.

A) maternal effect
B) gap
C) pair rule
D) segment polarity
E) Hox

Question 73

Nucleic acid hybridization was used to test which of the following hypotheses about Hox genes?

A) Hox genes are transcription factors.
B) Hox genes were derived from duplications of a single ancestral gene.
C) Hox genes are responsible for the identity of segments in the developing embryo.
D) Hox genes are maternal effect genes.
E) Hox genes encode morphogens.

Question 74

The even skipped gene in Drosophila received its name because mutations in that gene often lead to embryos missing the even numbered segments. Based on this information, what is the most likely class of gene to which even skipped would belong?

A) Maternal effect
B) Gap
C) Pair rule
D) Segment polarity
E) Hox

Question 75

In humans, the cells of the _______ have the highest concentration of _______.

A) thumb; MADS
B) little finger; MADS
C) thumb; Shh
D) little finger; Shh
E) thumb; Nanos

Question 76

A word derived from the Greek for "origin of form," _______, refers to the process by which differentiated cells are shaped into the multicellular body and all its organs.

Question 77

Which of the following statements about the MADS box genes in Arabidopsis thaliana is true?

A) They stimulate production of the leafy gene.
B) They code for subunits of transcription factors.
C) Gene regulation is combinatorial.
D) Both a and b
E) Both b and c

Question 78

Which of the following represents the correct gene action sequence in the body segmentation of Drosophila?

A) Segment polarity, pair rule, gap
B) Gap, segment polarity, pair true
C) Gap, pair rule, segment polarity
D) Bithorax, pair rule, segment polarity
E) None of the above

Question 79

The expression of hunchback in Drosophila is stimulated by _______ and inhibited by _______.

A) Nanos; bicoid
B) Nanos; Antennapedia
C) Bicoid; Antennapedia
D) Bicoid; nanos
E) Antennapedia; bicoid

Question 80

In different concentrations, developmental signals called _______ provide different positional information.

A) MADS box genes
B) transcription factors
C) morphogens
D) segment polarity factors
E) pair rule factors