TED-Ed: Insights into cell membranes via dish detergent - Ethan Perlstein

The video explores the structure and function of cell membranes, emphasizing their need to be both sturdy and flexible. It traces the history of membrane research, starting with Agnes Pockels' observations in the late 1800s and continuing with Irving Langmuir and Katharine Blodgett's work in the 1920s. The video highlights the pivotal experiment by Evert Gorter and Francois Grendel, which demonstrated that cell membranes are bilayers. This experiment, involving the extraction of lipids from red blood cells, provided crucial insights into cellular architecture long before the discovery of DNA's double-helix structure.

Why is a cell membrane compared to a fishnet stocking?

• Because it is very strong and rigid

• Because it is too leaky and easily torn

• Because it is made of metal

• Because it is completely impermeable

What did Agnes Pockels discover about detergents?

• All detergents dissolve grease in the same way

• Detergents have no effect on grease

• Different detergents dissolve grease differently

• Detergents are made of metal

What did Irving Langmuir and Katharine Blodgett find about oil molecules?

• They form a double layer on water

• They are made of metal

• They have a water-loving and a water-loathing side

• They dissolve completely in water

What was the main finding of Gorter and Grendel's experiment?

• Cell membranes are made of a single layer

• Cell membranes are made of metal

• Cell membranes are made of a bilayer

• Cell membranes are impermeable

How did Gorter and Grendel's experiment demonstrate the bilayer structure?

• By measuring the thickness of a single lipid layer

• By comparing the surface area of a monolayer to intact cells

• By observing the color change in lipids

• By using metal trays to hold the lipids