Question

Which of the following technique is used to study current flow across a single ion channel ?

• A. Patch clamp
• B. Voltage clamp
• C. lontophoresis
• D. Galvanometry

Answer 1

The Correct Option is A

Start by splitting the options into single-channel versus whole-cell methods. Galvanometry only reads a current, and iontophoresis pushes ions or drugs across tissue, so both are out immediately because neither isolates a channel. That leaves the two clamp methods. Voltage clamp fixes the membrane potential of the entire cell and reads the summed current from all channels, so it cannot resolve one channel. Patch clamp is different: a polished micropipette presses onto the membrane and forms a tight gigaohm seal over a microscopic patch holding only one or a handful of channels. Because the seal is so tight, the only current the electrode sees is what crosses that patch, giving the elementary single-channel record. That is exactly what the stem wants, so option (a) wins. Pearl to lock in: Neher and Sakmann developed patch clamp and earned the 1991 Nobel Prize, and it is the workhorse for neurons, cardiac and skeletal muscle, and beta cells.