Biology (Raven), 10th Edition

Chapter 19: Cellular Mechanisms of Development

Post-Test

1
Why are embryonic stem cells so enticing to researchers looking for solutions to many medical problems?
A)These cells can develop into any tissue in the animal.
B)Stem cells give rise to a single cell type, and so are predictable in culture.
C)These cells are easily obtained from the outer cell layer of a 5 day old embryo.
D)It is simple to alter the genetic content of these cells by use of microinjection or other technologies.
E)These cells are particularly sensitive to environmental cues and so can be coached into new, rarely expressed, developmental pathways.
2
What is the standard test for determination of cellular fate in an embryonic tissue?
A)Remove some cells and see if they form a new individual in a petri dish.
B)Place them next to undifferentiated cells and see whether these other cells change their developmental fate.
C)Introduce a new nucleus to the cells in question to see if they alter their developmental pathway.
D)Extract mRNA from the cell to see what kinds of gene expression have occurred.
E)Transplant cells from one end of an embryo to another and see if the structure which forms was consistent with the source location or the transplanted position.
3
During gastrulation, cells take up different positions with respect to each other, eventually forming the primary germ layers. What happens if the extracellular matrix (ECM) is exposed to antibodies which adhere to fibronectins and integrins?
A)The cell would develop normally, although slowly.
B)An inflammation response would activate the immune system, which would clear away the antibodies to allow development to continue.
C)Cell migration would occur too quickly because the ECM would not hold together appropriately.
D)Cell proliferation would increase because the cells would drift apart, activating cell division programs which are repressed by high cell density.
E)Binding of cells to fibronectin in the ECM is blocked and gastrulation is inhibited.
4
Contrast cell division in adult frogs from that in the early blastomere stage?
A)There is almost no G1 stage in the blastomere cell cycle.
B)There is almost no G2 stage in the adult cell cycle.
C)Cyclin is not involved in regulating cell divisions in the blastomere cells.
D)The zygote does not contain much mRNA for cyclin.
E)All of the above are legitimate differences between adult and blastomere cell cycles.
5
How does therapeutic cloning solve the problems associated with tissue rejection?
A)Therapeutic cloning inserts specific genes to block the immune system's ability to reject the new tissue.
B)Therapeutic cloning results new tissues unrecognizable to the immune system.
C)Blastomeric cells "learn" from adjacent tissues the correct developmental patterns necessary to immolate "self" markers.
D)Since stem cells are cloned from a person's own tissues in therapeutic cloning, they pass the immune system's "self" identity check, and the body readily accepts them.
E)Therapeutic cloning has no influence on tissue acceptance or rejection.
6
All animals (sponges, insects, primates, etc.) all contain Hox or Hox-like genes which stimulate developmental patterns. These are all absent from plants and fungi. What is the most likely explanation for the prevalence of these genes and gene clusters in the animal evolutionary line?
A)Because animals are the only creatures which show bilateral body plans, these genes are required for their proper development.
B)The presence of a Hox gene is necessary and sufficient for the establishment of an animal lifestyle.
C)Because more complex body plans are associated with clusters of Hox genes and evolution requires increasing complexity, these genes are selected for naturally.
D)An organism line which is ancestral to contemporary animals benefited from the developmental regulation afforded from the Hox genes, and these benefits have persisted through evolutionary time.
E)All of the above are plausible explanations.
7
If apoptosis was blocked in human development, which of the following might most likely occur?
A)The brain would become larger and more complex.
B)The dorsal/ventral axis would fail to develop properly.
C)Embryonic stem cells would differentiate more quickly.
D)Assymetric cell divisions would occur less frequently.
E)Webbed fingers and toes might be seen in the newborn.
8
The process of determination, commits a cell to a particular developmental pathway prior to its
A)Differentiation
B)Growth
C)Division
D)Death
E)Development
9
Animals regulate the following processes to achieve morphogenesis:
A)The number, timing, and orientation of cell divisions;
B)Cell growth and expansion;
C)Changes in cell shape;
D)Cell migration; and cell death.
E)All of the above
10
Although plants have homeobox-containing genes, they do not possess complexes of Hox genes similar to the ones that determine regional identity of developing structures in animals. Instead, the predominant homeotic gene family in plants appears to be the
A)Plant-specific Hox genes.
B)Bicoid genes
C)Nanos genes
D)Meristematic genes
E)MADS-box genes.
11
Cells that die due to injury typically swell and burst, releasing their contents into the extracellular fluid. This form of cell death is called
A)apoptosis.
B)programmed cell death.
C)lysis.
D)necrosis.
E)Morphogenesis
12
Which of these is involved with establishing the dorsal/ventral axis in Drosophilia?
A)Bicoid
B)Macho-1
C)Fraternal mRNA
D)Nanos
E)Dorsal transcription factor
13
In early stages of vertebrate cleavage, successive blastomeres
A)are equal in size to the original zygote.
B)become smaller and smaller.
C)grow larger and larger.
D)migrate to positions of future development.
E)begin immediate differentiation.
14
Animal pole cells will develop into which of the following?
A)Epiderm
B)Endoderm
C)Neural tissue
D)Ectoderm
E)Notoderm
15
For somatic cell nuclear transfer to be successful, the egg and the donated nucleus must be
A)at the same stage in development.
B)from the same organism.
C)at the same stage of the cell cycle.
D)fused in vivo.
E)unable to undergo cell division.
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