* not completed

. A fertilized egg is called:

an embryo correct incorrect

a zygote correct incorrect

a blastula correct incorrect

an oocyte correct incorrect

* not completed

. Which of the options given is a germ cell?

cells of the gonads correct incorrect

intestinal cells correct incorrect

sperm and eggs correct incorrect

zygotes correct incorrect

* not completed

. Which of the options given reflects Weismann's model of development?

somatic development and change does not contribute directly to the characteristics of the next generation correct incorrect

factors, or "determinants", in the nucleus regulate development correct incorrect

asymmetric divisions resulted in unequal distribution of developmental determinants to daughter cells correct incorrect

all of the options given were important to Weismann's view of biological development correct incorrect

* not completed

. Which statement best describes the relationship between genotype and phenotype?

'Genotype' and 'phenotype' both describe the physical properties of cells and organisms, just using different words or symbols. correct incorrect

Phenotype is entirely the consequence of a cell's genotype, which is why we now recognize the principle of 'genetic determinism.' correct incorrect

The genes found in a cell are that cell's genotype, and genes directly control a cell's phenotype. correct incorrect

The genotype determines what proteins a cell contains, and the proteins in turn determine the cell's properties, or phenotype. correct incorrect

* not completed

. The experiments of Spemann and Mangold first defined what feature of amphibian embryos?

the zygote correct incorrect

the blastopore correct incorrect

the organizer correct incorrect

the blastocoel correct incorrect

* not completed

. Which of these animals is a vertebrate 'model organism' used in the study of development?

Caenorhabditis elegans correct incorrect

Drosophila melanogaster correct incorrect

Homo sapiens correct incorrect

Xenopus laevis correct incorrect

* not completed

. Which would qualify as a dominant allele of a gene?

an allele that confers a phenotype on the organism when heterozygous; that is, when present in only one copy correct incorrect

an allele that confers a phenotype only when both copies of the gene are mutant; that is, when homozygous correct incorrect

an allele that is commonly found in wild populations, as opposed to alleles found in laboratory strains or when a pathological condition is present correct incorrect

an allele that confers a normal phenotype under some conditions, but confers a different, mutant phenotype when conditions such as elevated temperature are present correct incorrect

* not completed

. Which of the basic developmental processes given here is most dependent on cellular movements?

cell differentiation correct incorrect

growth correct incorrect

morphogenesis correct incorrect

pattern formation correct incorrect

* not completed

. The establishment of the anterior-posterior or dorsal-ventral body axes is called:

division correct incorrect

pattern formation correct incorrect

morphogenesis correct incorrect

differentiation correct incorrect

* not completed

. The folding of sheets of cells, the migration of cells, and cell death are all mechanisms of:

cleavage division correct incorrect

pattern formation correct incorrect

morphogenesis correct incorrect

growth correct incorrect

* not completed

. The process by which developing cells achieve their functional, mature identity as liver, or muscle, or nerve is called:

pattern formation correct incorrect

differentiation correct incorrect

morphogenesis correct incorrect

growth correct incorrect

* not completed

. Genes control development by:

controlling where and when proteins are synthesized correct incorrect

containing small preformed body parts and organs that become "expressed" during development correct incorrect

directly controlling phenotypes, without intermediates or influence from the environment correct incorrect

containing instructions which describe in detail the final form to be achieved during development correct incorrect

* not completed

. The pathway from a gene to a protein in eukaryotic cells involves:

first, transport of mRNA, then its processing, then transcription, then translation correct incorrect

first, transcription of the RNA, then its transport, then processing, then translation correct incorrect

first, translation of the RNA, then its transport, then its processing, then transcription correct incorrect

first, transcription of RNA, then its processing, then its transport, then translation correct incorrect

* not completed

. Which aspect of cellular regulation operates after a protein has been synthesized?

post-translational modification correct incorrect

RNA processing correct incorrect

transcriptional control correct incorrect

translational control correct incorrect

* not completed

. Which term could be used to refer to a segment of DNA?

cis-regulatory module correct incorrect

differential gene expression correct incorrect

gene regulatory protein correct incorrect

transcription factor correct incorrect

* not completed

. What is the difference between "fate" and "specification"?

Cell fate describes the allocation of cells to the germ layers, ectoderm, mesoderm, or endoderm, whereas specification describes the exact tissues that each cell will ultimately become. correct incorrect

The fate map of an embryo does not change during development - the fate map of an egg is the same as the fate map of a late blastula - whereas the specification map of an embryo changes continually as the embryo's development proceeds. correct incorrect

The specification state of a cell is determined by transplantation of cells to recipient embryos, whereas the fate of a cell is determined by the culture of those cells in an artificial medium. correct incorrect

The fate of a cell is determined by labelling that cell and following it during normal development, whereas the specification state of a cell is determined by culturing a cell in an artificial medium and observing what tissues form from it. correct incorrect

* not completed

. How could you produce a chimeric mouse?

Divide a morula into two separate clusters of blastomeres and let each cluster form an embryo. correct incorrect

Introduce cells from the inner cell mass of one blastocyst into the inner cell mass of another blastocyst of the same genetic constitution. correct incorrect

Divide a fertilized mouse egg into two halves and let each develop separately. correct incorrect

Introduce cells from the inner cell mass of one blastocyst into the inner cell mass of another blastocyst of a different genetic constitution. correct incorrect

* not completed

. Which of the options given is not a mechanism by which cells communicate with each other?

transcription factors are secreted from one cell and taken up by the target cell, where they influence gene expression correct incorrect

cell surface molecules on adjacent cells interact and initiate a signal transduction process that influences cellular behavior and gene expression correct incorrect

cells secrete proteins and small hydrophilic molecules, which interact with cell surface receptors on target cells and initiate a signal transduction process that influences cellular behavior and gene expression correct incorrect

cells secrete small hydrophobic molecules which diffuse into target cells, interact with cytoplasmic receptors, and influence gene expression correct incorrect

* not completed

. Signal transduction can involve:

interaction of a molecule with a receptor at the cell surface correct incorrect

intracellular modification of proteins by phosphorylation correct incorrect

production of second messengers such as cAMP correct incorrect

all of the options given can be components of a signal transduction pathway correct incorrect

* not completed

. A morphogen is

a cell or group of cells that signal other cells to become determined in a specific way correct incorrect

a gene that causes a cell or group of cells to adopt a particular shape correct incorrect

a signaling molecule that causes the differentiation of neighboring cells correct incorrect

a signaling molecule that confers concentration-dependent positional information correct incorrect

* not completed

. What distinguishes stem cells from other cell types?

Although all cell types can divide, only stem cells differentiate after division. correct incorrect

Stem cells are able to divide to produce populations of cells that differentiate into a related set of cells. correct incorrect

Stem cells divide asymmetrically to give rise to one daughter cell that remains a stem cell, and a second daughter cell that differentiates into one or more cell types. correct incorrect

Stem cells have a special type of cell division in which they form small stems that then pinch off to give rise to the daughter cell. correct incorrect

* not completed

. How does organismal development evolve to give rise to new forms and species?

A structure like the fin of a fish evolves into a structure like a human hand through the needs of the organism for a hand rather than a fin. correct incorrect

Changes in genes that will be favored by natural selection will be induced, and thereby produce favorable changes in development. correct incorrect

Changes in genes will alter an organism's development, and if the new developmental patterns are favored by the environment they will be retained through natural selection. correct incorrect

The characteristics acquired by the organism during its lifetime are passed on to the offspring; if the changes are favorable to the organism, they will eventually come to be encoded in the genes that govern development. correct incorrect