A 75-year-old man goes to the hospital emergency department and faints. Five minutes later he is alert. An EKG shows 75 P waves per minute and 35 QRS waves per minute with a normal QRS width. Which of the following is the likely diagnosis?

#Question id: 7187

#Unit 5. Developmental Biology

Following statements regarding to feedback loops during limb development.

A. When the limb bud is relatively small, an initial positive feedback loop is established between Fgf10 produced in the mesoderm and Fgf8 produced in the ectoderm, promoting limb outgrowth.

B. As the limb bud grows, the ZPA is established, and another regulatory loop is created by inhibiting the BMP in mesoderm and maintain FGF expression.

C. In anterior region of the limb bud, Fgf8 positively regulates Etv4/5, which in turn repress Shh in this region, further reinforcing the posterior-to-anterior gradient of Shh from the ZPA.

D. In posterior region of the limb bud, Fgf8 positively regulates Etv4/5, which in turn repress Shh in this region, further reinforcing the posterior-to-anterior gradient of Shh from the ZPA.

Which of the following combinations are incorrect?

#Question id: 31315

#Unit 6. System Physiology – Plant

#Question id: 17674

#Unit 8. Inheritance Biology

#Question id: 1847

#Unit 4. Cell Communication and Cell Signaling

Which of the following statements is TRUE of DNA vaccines?

#Question id: 9273

#Unit 6. System Physiology – Plant

In the higher excited state, chlorophyll is extremely unstable; it rapidly gives up some of its energy to the surroundings as heat, and enters the lowest excited state, the excited chlorophyll has four alternative pathways for disposing of its available energy: fluorescence, Heat loss, energy transfer, photochemistry; all process takes place in which wavelength,