Palytoxin is a deadly compound found in certain marineanimals. When scientists first isolated palytoxin from seacorals in the 1970s, they did not know how it affectedpeople exposed to it. In time, they began to suspect thatthe toxin was interfering with the sodium-potassium pump.Researchers have measured the effect of palytoxin on iontransport through the sodium-potassium pump using thepatch-clamp technique. This involves using a fine-tippedmicroelectrode to measure the electric current across pumpsin the cell membrane. In this activity, you will examine someof the researchers' results and conclusions.Procedure1. Read the following observations that researchers madeafter adding palytoxin to a membrane, and then answerthe questions.• Observation 1: The current across a single pumpjumped from 0 picoamperes to 1 picoamperes.• Observation 2: When ATP was added to thecytoplasm-facing side of the membrane, the currentacross a group of pumps increased by a factor of 8times.Observation 3: A molecule 0.75 nm in diameter wasable to pass through the pump. (For comparisonpurposes, a hydrogen atom measures 0.1 nm indiameter.)Questions1. How does the patch-clamp technique help researchersstudy ion transport across cell membranes?2. In general, about 107-108 ions/s pass through an openion channel. In contrast, only 10² ions/s pass throughan ion pump. How would you expect the strength of anelectric current across an ion channel to compare withthe strength across an ion pump?3. What does Observation 1 suggest about ion flowthrough the sodium-potassium pump when palytoxinis added?4. Given that the sodium-potassium pump is a formof active transport, suggest an explanation forObservation 2.5. What does Observation 3 suggest about the size of thepassage through the sodium-potassium pump?

NOTE: according to the answering guidelines, I am going to answer only first three parts of the…

Questions 1. How does the patch-clamp technique help researchers study ion transport across cell membranes? 2. In general, about 107-108 ions/s pass through an open ion channel. In contrast, only 10² ions/s pass through an ion pump. How would you expect the strength of an electric current across an ion channel to compare with the strength across an ion pump? 3. What does Observation 1 suggest about ion flow through the sodium-potassium pump when palytoxin is added?

Questions 1. How does the patch-clamp technique help researchers study ion transport across cell membranes? 2. In general, about 107-108 ions/s pass through an open ion channel. In contrast, only 10² ions/s pass through an ion pump. How would you expect the strength of an electric current across an ion channel to compare with the strength across an ion pump? 3. What does Observation 1 suggest about ion flow through the sodium-potassium pump when palytoxin is added?

Biomedical Instrumentation Systems

1st Edition

ISBN:9781133478294

Author:Chatterjee

Publisher:Chatterjee

Chapter19: Biomedical Laboratory Instrumentation

Section: Chapter Questions

Problem 9P

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