A red blood cell is placed in a hypertonic solution and rapidly shrinks. A second red blood cell sample is treated with a compound that reduces the number of functional water channels in the membrane, then placed in the same hypertonic solution. These treated cells shrink more slowly than untreated cells. Identify the tonicity of the solution and predict the direction of net water movement for both samples. Explain why reducing water channels slows the volume change without changing which direction water will move. Predict what would happen if an ion channel opened that allowed potassium to leave the cell while in the hypertonic solution, and explain how that would affect water movement.

A genetic defect prevents ribosomes from attaching to the rough endoplasmic reticulum. Which outcome is most likely for proteins that normally enter the secretory pathway?

A toxin damages mitochondrial inner membranes. Which cellular function is most immediately impaired?

During childbirth, uterine contractions become stronger as labor progresses. Which feature best identifies this as positive feedback rather than negative feedback?

A researcher designs a drug that forms many hydrogen bonds with water. Which property is most likely enhanced by this design?

A lower pH indicates a lower hydrogen ion concentration than a higher pH.

A patient has impaired electron transport chain function. Which immediate effect is most likely?

Water’s cohesion is primarily due to hydrogen bonding between water molecules.

What did Rutherford’s gold foil experiment tell about the atom?

Which scenario best represents an ionic interaction in the body?