Reference no: EM1387047

1. Determine which of the following methods can be used to identify the mesodermal cells that give rise to the vertebrate limb?

A. Removing certain groups of cells and observing whether or not a limb forms in their absence

B. Transplanting certain groups of cells to a new location and observing whether or

not a limb grows in this new location

C. Marking groups of cells and observing whether or not their descendants partake in

limb development

D. All of the above

E. None of the above

2. Multilimbed Pacific tree frogs (Hyla regilla) have been observed in nature with multiple legs originating from the same site on the body. This has been attributed to the infestation of larval frog abdomen by parasitic trematode worm eggs. Which of the following explains how this infestation can cause extra limbs in frogs?

A. The trematode eggs are activating gene expression in an existing limb bud to form

new legs

B. The trematode eggs are splitting the developing limb buds into segments, and each

segment develops into a leg

C. The tremadode eggs are inducing the production of a new limb bud at the same

site as the existing limb bud

D. The trematode eggs are somehow transplanting a new limb bud at the same site as

the existing limb bud

3. What factors are necessary for the formation of angioblasts from mesoderm cells?

A. FGF

B. VEGF

C. ANG1

D. FGF and VEGF

E. FGF, VEGF, aand ANG1

4. If forelimb mesoderm is replaced with hindlimb mesoderm, the forelimb will now develop as:

A. Forelimb

B. Hindlimb

C. No limb will grow

D.The limb will have forelimb and hindlimb structures

5. The faust gene in zebrafish functions similarly to miles apart in that it

A. Is required for cardiac looping

B. Is required for the production of the endocardial cushions

C. Is required for the migration of cardiac precursor cells

D. Is required for the production blood islands

6. The directionality of the movement of cardiac precursor cells in chicken embryos is in part toward the anterior. It is thought that a concentration gradient highest in the anterior and lowest in the posterior of fibronectin in the gut endoderm is responsible for this movement. What would you expect would happen to the movement of the cardiac precursor cells if you rotated the endoderm 180 degrees?

A. Cardiac precursor cells will migrate normally

B. Cardiac precursor cells will cease to migrate

C. Cardiac precursor cell migration will be reversed

D. None of the above

7. Which of the following results shows the necessity of FGF for the specification of hemangioblasts from mesoderm?

A. Mesoderm will not generate hemangioblasts when the FGF signal is missing

B. Mesoderm will generate hemangioblasts when the only signal present is FGF

C. Both A and B

D. Neither A nor B

8. There are several constraints on blood vessel formation that produce similar looking circulatory systems in within a given species. Which of the following is considered a constraint?

A. Physiological constraints

B. Evolutionary constraints

C. Physical constraints

D. All of the above

9. In mice, if you knock-out production of the Tbx5 transcription factor, the lateral plate mesoderm fails to produce FGF10. Which of the following phenotypes would you expect to see in a Tbx5 mutant?

A. A Tbx5 mutant will not produce a forelimb

B. A Tbx5 mutant will not produce proximal limb structures

C. A Tbx5 mutant will not produce distal limb structures

D. A Tbx5 mutant will produce a normal limb

10. The heart arises from the:

A. Somatic mesoderm

B. Splanchnic mesoderm

C. Endoderm

D. Ectoderm