Test Prep for AP® Courses

One type of mutation in the CFTR protein prevents the transport of chloride ions through the channel. Which of the following is most likely to be observed in the lungs of patients with this mutation?

Arsenic poisoning disrupts ATP production by inhibiting several of the enzymes in the oxidative phosphorylation pathway. Some of the symptoms of arsenic poisoning are similar to cystic fibrosis (CF); a hereditary disorder that results in difficulty breathing and frequent lung infections. What impact might arsenic poisoning have on components of the plasma membrane and transport that result in CF-like symptoms?

In individuals with normally functioning CFTR protein, which substances are transported via active transport?

The sodium-potassium (\text{Na}^{+}/\text{K}^{+}) pump functions like an anti-porter transporting \text{Na}^{+} \! and \text{K}^{+} {\!} across membranes using ATP. This protein spans the membrane with intracellular and extracellular domains. It has a binding site for \text{Na}^{+} {\!}, \text{K}^{+} {\!}, and ATP. An experiment was conducted to determine the locations of these binding sites. Artificial cells were created and incubated in buffers containing ATP, ouabain (or oubain), \text{Na}^{+} {\!}, and \text{K}^{+} {\!} in varying combinations inside and outside of the cell as indicated in the chart. The transport of \text{Na}^{+} {\!} and \text{K}^{+} {\!} was measured to determine activity of the \text{Na}^{+}/\text{K}^{+} {\!} pump. Which of the following conclusions is supported by the data?

Paramecia are unicellular protists that have contractile vacuoles to remove excess intracellular water. In an experimental investigation, Paramecia were placed in salt solutions of increasing osmolarity. The rate at which a Paramecium's contractile vacuole contracted to pump out excess water was determined and plotted against osmolarity of the solutions, as shown in the graph. Which of the following is the correct explanation for the data?

What is most likely to happen if Paramecia, pictured here, are moved from a hypertonic solution to solutions of decreasing osmolarity?

Describe the Na⁺/K⁺ pump, labeling the binding sites for Na⁺, K⁺, and ATP. Explain how the data indicates the location of the binding sites for Na⁺ and K⁺ on the pump. Based on the data, which statement describes the location of the binding sites for Na⁺ and K⁺ on the pump?

An experiment was set up to determine the movement of molecules through a dialysis-tubing bag into water. A dialysis-tubing bag containing 5\% lactose and 5\% fructose was placed in a beaker of distilled water, as illustrated. After four hours, fructose is detected in the distilled water outside of the dialysis-tubing bag, but lactose is not. What conclusions can be made about the movement of molecules in this experiment?

This is the 3D structure of clathrin, with an individual subunit highlighed in blue. What is a functional reason for this structure?

Which of the following statements appropriately describe the role of clathrin in neutrophils based on your understanding of phagocytosis?

Mast cells produce signals that activate inflammation. Neutrophils are phagocytic white blood cells. Monocytes are the largest type of white blood cell that engulf pathogens. Based on the information provided, which cell types produce endosomes?