TLS Online TPP Program

#Question id: 807


Which of the following forces can stabilize a normal DNA double-helix?

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. Base-stacking is a non-covalent interaction that occurs between the relatively hydrophobic bases in the interior of the helix.

  2. Base-pairing is a non-covalent interaction that occurs between adjacent bases in the same strand of the DNA molecule.

  3. The hydrophilic sugar-phosphate groups are on the exterior of the helix where they can interact with each other.

  4. The deoxyribose rings form N-glycosidic bonds with the phosphate groups that link neighboring nucleotides.

More Questions
TLS Online TPP Program

#Question id: 11075

#Unit 7. System Physiology – Animal

A 65-year-old man with emphysema due to 34 years of cigarette smoking is admitted to hospital due to dyspnea. With further tests the mean pulmonary arterial pressure is determined to be 45 mm Hg at rest. He is hypoxic (PO2 = 49 mm Hg), hypercapnic (85 mm Hg), and slightly acidotic. The cardiovascular and oxygen changes are due to which of the following?

TLS Online TPP Program

#Question id: 11076

#Unit 7. System Physiology – Animal

Which of the following will decrease pulmonary blood flow resistance?

TLS Online TPP Program

#Question id: 11077

#Unit 7. System Physiology – Animal

A person’s normal tidal volume is 400 ml with a dead space of 100 ml. The respiratory rate is 12 breaths/min. The person is placed on ventilator for surgery and the tidal volume is 700 with a rate of 12. What is the approximate alveolar Pco2 for this person?

TLS Online TPP Program

#Question id: 11078

#Unit 7. System Physiology – Animal

A child has been eating round candies approximately 1 and 1.5 cm in diameter and inhaled one down his airway blocking his left bronchiole. Which of the following will describe the changes that occur?


TLS Online TPP Program

#Question id: 11079

#Unit 7. System Physiology – Animal

The diffusing capacity of a gas is the volume of gas that will diffuse through a membrane each minute for a pressure difference of 1 mm Hg. Which of the following gases is often used to estimate the oxygen diffusing capacity of the lungs?

TLS Online TPP Program

#Question id: 11080

#Unit 7. System Physiology – Animal

The O2-CO2 diagram here shows a ventilation-perfusion ratio line for the normal lung. Which of the following best describes the effect of decreasing ventilation-perfusion ratio on the alveolar Po2 and Pco2?