Biologists have been able to produce mice that lack functioning genes for aquaporins. How would the urine of these mice compare to that of mice with normal aquaporins? a. lower volume and lower osmolarity b. lower volume and higher osmolarity c. higher volume and lower osmolarity d. higher volume and higher osmolarity

Verified step by step guidance

1. Step 1: Understand the role of aquaporins. Aquaporins are proteins that form pores in the cell membrane, allowing water to move in and out of the cell. They play a crucial role in the kidney's ability to concentrate urine.
2. Step 2: Consider the effect of lacking aquaporins. If the mice lack functioning genes for aquaporins, their cells would be less permeable to water. This means that less water would be reabsorbed from the urine in the kidneys.
3. Step 3: Predict the effect on urine volume. If less water is reabsorbed, the volume of urine would be higher.
4. Step 4: Predict the effect on urine osmolarity. If less water is reabsorbed, the urine would be less concentrated, meaning it would have a lower osmolarity.
5. Step 5: Match your predictions to the answer choices. The urine of mice lacking functioning genes for aquaporins would have a higher volume and lower osmolarity, so the correct answer is (c).

Key Concepts

Aquaporins

Aquaporins are specialized membrane proteins that facilitate the transport of water across cell membranes. They play a crucial role in regulating water balance in various tissues, particularly in the kidneys, where they help concentrate urine by allowing water reabsorption. Mice lacking functional aquaporins would struggle to retain water, leading to significant changes in urine composition.

Osmolarity

Osmolarity refers to the concentration of solute particles in a solution, which affects the movement of water across membranes. In the context of urine, higher osmolarity indicates a more concentrated solution, while lower osmolarity suggests a more diluted one. The presence or absence of aquaporins directly influences the osmolarity of urine by determining how much water is reabsorbed in the kidneys.

Urine Volume

Urine volume is the amount of liquid waste produced by the kidneys and excreted from the body. It is influenced by factors such as hydration status, solute concentration, and the functionality of renal transport mechanisms, including aquaporins. Mice without functioning aquaporins would likely produce a higher volume of urine due to their inability to reabsorb water effectively, leading to more dilute urine.