This document contains a biology exam question and sample answer regarding plasma membranes and cell transport. Part A asks about structures labeled on a plasma membrane diagram and describes active transport. Part B asks about the effect of respiratory poison on transport across the membrane. Part C presents data from a study on red blood cell concentration and asks students to analyze the results and determine isotonic, hypotonic, and hypertonic solutions. The sample answer identifies the labeled structures, explains active transport, discusses the poison's effect on respiration and transport, names the cell as a red blood cell, determines blood plasma concentration is isotonic, and predicts the red blood cell will burst in distilled water due to it being hypotonic.