Determined Cell Will Keep Its Determination No Matter Where It Is Placed In An Embryo.

1. 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.

2. The cloning experiments on sheep, frogs, and mice showed 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.

3. The term "embryonic induction" describes a process in which a group of cells a. influences the development of another group of cells.

b. triggers the cell movements in an embryo.

c. stimulates the transcription of their own genes.

d. organizes the egg cytoplasm before fertilization.

e. makes a "fate map" of the embryo.

4. The term "therapeutic cloning" describes a. modification of a clone by a transgene.

b. combining nuclear transplantation and stem cell differentiation.

c. making clones that produce useful drugs.

d. producing embryonic stem cells for transplantation.

e. making many identical copies of an organism.

5. 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 microfilament action.

c. They are products of specific genes in the mother fruit fly.

d. They often produce large-scale effects in larvae.

e. They have been studied by the transfer of cytoplasm from egg to egg.

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

7. Which statement about embryonic 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 induce itself.

e. The chemical identification of specific inducers has been difficult.

8. In the process of body segmentation in Drosophila larvae, a. the first steps are specified by homeotic 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. segmentation is the same as in earthworms.

9. Homeotic mutations a. are often so severe that they can be studied only in larvae.

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.

10. Which statement about the homeobox is not true?

a. It is transcribed and translated.

b. It is found only in animals.

c. All proteins containing the homeodomain bind to DNA.

d. It is a stretch of DNA shared by many genes.

e. Its activities often relate to pattern formation.

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Essentials of Human Physiology

Essentials of Human Physiology

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  • Pirjo
    Which statement about determination is true differentiation precedes determination?
    9 years ago

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