Exam 2 Module 10

Major morphological changes can result from mutations in developmental regulatory genes. short-term environmental changes. alterations in the time or place of expression of genes. Both a and c All of the above

Hox genes code for enzymes. are clustered in a similar way in both Drosophila and mouse embryos. are present in single copies. control dorsal-ventral pattern formation in Drosophila. code for termination factors.

Location of a cell may be critical in the determination of its ultimate fate during development, as in the development of vertebrate limbs. This fact arises from a gradient in the concentration of ZPA. expression of organ identity genes. expression of homeotic genes. a gradient in the concentration of the morphogen, Sonic hedgehog. the unequal distribution of transcription factors.

The genes that determine the fate of cells in the _______ of a flowering plant's shoot apex are called _______ genes. These genes code for _______. whorl; organ identity; morphogens meristem; organ identity; transcription factors meristem; homeotic; morphogens meristem; organ identity; LEAFY protein whorl; homeotic; transcription factors

Which of the following is the last set of genes to turn on in the Drosophila embryo? Maternal effect genes Segment polarity genes Homeotic genes Gap genes Pair rule genes

Conserved developmental genes can lead to _______ evolution. divergent convergent parallel phenotypic linear None of the above

Apoptosis occurs by similar mechanisms in both nematodes and humans. is random cell death. is not an important process in neuronal development of humans. is not an important process in the development of nematodes. is a process controlled by a single gene.

Which of the following statements about determination is false? Fates of cells become more restricted during development. Differentiation precedes determination. One cannot tell whether a cell is determined by its appearance. Most cells are determined early in their life cycle.

Evolutionary modifications result from rapid mutations of the genes that control development. generally occur in large steps. such as wings, likely evolved independently in insects and vertebrates. usually result in entirely new anatomical features over a short time period. are facilitated by the conservation of the genes that regulate development.

A homeobox is not present in plants. binds to DNA. is another name for a homeodomain. is a protein sequence. is a DNA sequence present in many genes that code transcription factors.

Plants may be cloned from _______ somatic cells, while animals have been cloned by _______ into/with_______ eggs. differentiated; nuclear transfer; enucleated embryonic; cell fusion; nucleated embryonic; nuclear transfer; nucleated differentiated; cell fusion; nucleated

Which of the following statements about inducer molecules is false? Inducer molecules act through signal transduction pathways. Inducers bind to receptors on the plasma membrane of target cells. Inducers can form concentration gradients. Inducer molecules can activate transcription factors. Inducers molecules are generally produced by the same cells they affect.

In a vertebrate embryo, cell division and differentiation may be mutually exclusive. arrest of the cell cycle blocks differentiation. transcription factors result in differential gene expression. rapid growth by cell division favors differentiation. Both a and c

Induced pluripotent stem cells are genetic transformants. may be produced from skin cells in vitro. can be induced to form many different tissues. offer some advantages over embryonic stem cells for therapeutic use. All of the above

Which of the following principles of evo-devo is not stated properly? Development is modular. Changing the timing of gene expression during development can lead to new body forms. New developmental mechanisms, rather than modifications of existing mechanisms, account for morphological evolution. Even distantly related organisms share similar molecular mechanisms for development. Developmental mechanisms have evolved to be responsive to environmental cues

The process of morphogenesis is the shaping of differentiated cells into the multicellular body and its organs. sets the developmental fate of a cell. is the process by which different cell types arise. is the increase in body size. All of the above

Stem cells are totipotent in animals. present in all parts of a mature plant. likely to be present in animal tissues that do not regenerate. multipotent in animals. found in just a few animal tissues.

The fate of a cell during development is not altered by reagents that interfere with microtubule formation. determined solely by inducers. influenced by cytoplasmic determinants. independent of gene expression. entirely controlled by nuclear gene expression.

Developmental modularity allows one part of an animal's body to change independent of another part. is controlled by a single "switch." is a consequence of the action of the genetic toolkit. does not involve spatial differences in gene expression. Both a and c

The anterior and posterior ends of a Drosophila embryo are determined by _______ genes that are active _______ fertilization and result in a gradient of the protein _______. organ identity; before and after; Nanos maternal effect; before and after; Hunchback segmentation; before and after; Bicoid maternal effect; before; Hunchback organ identity; after; Hunchback

Which statement about developmental processes is true? Biologists usually can observe determination in cells through microscopic studies. Differentiation of cells cannot occur unless morphogenesis has first occurred. Differentiation consists of the actual biochemical, structural, and functional changes of a cell. In an embryo, determination begins after the larval stage. Differentiation occurs in animal embryos but not in plant embryos.

A gene in Drosophila called even-skipped (eve) received its name because mutations in that gene often lead to embryos that are missing the even-numbered segments. Based on this information, even-skipped is most likely a _______ gene. maternal effect gap pair rule segment polarity Hox

Differences in the expression of the gene _______ account for many of the phenotypic differences between freshwater and marine forms of three-spine sticklebacks. bicoid Pax6 Pitx1 Ubx Gremlin

If the ZPA secreted more morphogen than normal, the most likely result would be two thumbs. five thumbs. five digits but no thumb. no little finger. no digits.

Which statement about the evolution of development is false? Nearly all evolutionary innovations are the result of modifications of previously existing mechanisms and structures. The genes that control development are highly conserved. If the necessary mutations occur, natural selection can act on any signaling pathway that affects development. Because modifications of developmental sequences are usually lethal, natural selection does not act on mutations that alter development.

If the anchor cell is destroyed in the embryo of the nematode Caenorhabditis elegans, the most likely outcome will be that no vulva will form. no anchorettes will form. secondary vulval precursors will become primary vulval cells. another cell will differentiate into an anchor cell. signals from the nematode's environment will direct epidermal cells to become a vulva.

If Gremlin expression were reduced in the cells that give rise to feet in ducks, the feet would be much smaller due to a heterochronic shift. the feet would be much larger due to a heterochronic shift. the feet would be more webbed than normal. the feet would be less webbed than normal. winglike structures would appear where the feet ordinarily would be.

Which statement best describes the differences between embryonic and induced pluripotent stem (iPS) cells? Embryonic stem cells are totipotent, whereas iPS cells are not. IPS cells are totipotent, whereas embryonic stem cells are not. Only iPS cells carry a vector containing extra copies of genes found within the cells. Only embryonic stem cells can be made to match the genome of the patient. IPS cells created from the patient's cells provoke an immune response, whereas donated embryonic stem cells do not.

Which statement about Hox genes (genes that control the body plan of an embryo along the anterior-posterior (head-tail) axis) is false? They are part of the so-called genetic toolkit. They are expressed in similar patterns in the embryos of both mice and flies. They are arranged in similar clusters of genes in both mice and flies. Because of their important functional roles, they evolved rapidly in both mammals and flies. They include a conserved region of base pairs called the homeobox.

In studies of gene expression, which observation would be the least likely? As the result of radically different developmental processes within an insect species, some members of the species have a pair of wings that its conspecifics lack. Expression of a gene that is important in developmental processes varies with temperature. A species of fish is much larger than fish in a closely related species because a gene affecting bone growth is expressed earlier in development in the larger fish than in the related species. The amino acid sequence of a Hox gene protein is extremely similar in nematodes and humans. One rodent species has a narrower face than all others, because in that species the expression pattern of a gene that is important in development is

Which of the following distinguishes insects from other arthropods such as centipedes? Insect Ubx promotes the expression of Distalless, whereas the Ubx of centipedes has no effect on Distalless expression. Insect Ubx inhibits the expression of Distalless, whereas the Ubx of centipedes activates Distalless expression. Insect Distalless promotes the expression of Ubx, whereas the Distalless of centipedes activates Ubx expression. Insect Distalless inhibits the expression of Ubx, whereas the Distalless of centipedes activates Ubx expression. Insect Distalless promotes the expression of Ubx, whereas the Distalless of centipedes inhibits Ubx expression.

Which type of cell is most likely to be totipotent? Stem cell from bone marrow Liver cell Larval gut cell Late gastrula cell Early-stage cleavage cell

Imagine you are working on a sea urchin embryo after gastrulation has begun. You isolate some of the cells that are inside the blastula/gastrula. They look unspecialized, but when you culture them in a dish outside of the embryo, they secrete skeletal spicules similar to those they would have eventually formed if they had remained in the embryo. From these results, you could propose that when you isolated these cells, they were already differentiated. undergoing apoptosis. totipotent. fully grown. determined.

Which statement about cloned animals is true? Cloning of extinct animals has been used to resurrect the wooly mammoth. Cloning has been used to preserve endangered species. Cloning of the sheep "Dolly" demonstrated the efficiency of this method of reproduction, in that all embryos transferred to a surrogate mother survived to birth. Cloning by transferring a nucleus from an embryo into an enucleated egg is less effective than transferring a nucleus from a mammary gland. The cloned sheep named "Dolly" was a clone of her birth mother.

In a hypothetical developmental biology experiment, researchers place a nonporous barrier between the alpha ludens (a made-up structure) and tissues that are supposed to develop into the beta ludens (also a made-up structure). If the beta ludens _______, it is most likely that signals from the alpha ludens are acting as _______ of the beta ludens. develops; inducers develops; microfilaments does not develop; microfilaments develops; transcription factors does not develop; inducers

Which sequence represents the correct cascade of gene action in determining the pattern of segmentation in Drosophila? Segment polarity, pair rule, gap Gap, segment polarity, pair rule Gap, pair rule, segment polarity Hox, pair rule, segment polarity Segment polarity, pair rule, maternal effect

In the normal course of development in Arabidopsis, a particular group of cells should develop into carpel tissue. If the expression of class B genes were also induced in those cells, they would develop into _______ tissue. carpel petal stamen sepal carpel and stamen

Which event(s) lead(s) to distinct patterns of gene expression within different cells of an embryo? Unequal distribution of genes among different cells, followed by induction Cytoplasmic segregation and induction Segregation of different chromosomes to different cells Genomic equivalence among all the cells and morphogenesis Segregation of yolk to the animal hemisphere

If the ZPA secreted more morphogen than normal, the most likely result would be two thumbs. five thumbs. five digits but no thumb. no little finger. no digits.