Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1-, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac-). During an condition  isolate  a second Lac– mutation, which you designate lac2-. Using P1 phage on this strain and use the resulting phage lysate to infect the lac2- strain, selecting for   Kanr   transductants. In this case, all 100   Kanr   transductants that are examined are Lac–. What does this result tell you about the relationship between the lac1- and lac2- mutations?

#Question id: 11750

#Unit 7. System Physiology – Animal

Which of the following best describes the concept of specificity in sensory nerve fibers that transmit only one modality of sensation?

#Question id: 11751

#Unit 7. System Physiology – Animal

Which of the following is an encapsulated receptor found deep in the skin throughout the body as well as in fascial layers where they detect indentation of the skin (pressure) and movement across the surface (vibration)?

#Question id: 11752

#Unit 7. System Physiology – Animal

Which of the following substances enhances the sensitivity of pain receptors but does not directly excite them?

#Question id: 11753

#Unit 7. System Physiology – Animal

Which of the following is an important functional parameter of pain receptors?

#Question id: 11754

#Unit 7. System Physiology – Animal

Use the following clinical laboratory test results:

Urine flow rate = 1 ml/min

Urine inulin concentration = 100 mg/ml

Plasma inulin concentration = 2 mg/ml

Urine urea concentration = 50 mg/ml

Plasma urea concentration = 2.5 mg/ml

What is the net urea reabsorption rate?

#Question id: 11755

#Unit 7. System Physiology – Animal

Which of the following solutions when infused intravenously would result in an increase in extracellular fluid volume, a decrease in intracellular fluid volume, and an increase in total body water after osmotic equilibrium?