TED-Ed: How do oysters make pearls? | Rob Ulrich

The video explores the formation and composition of pearls, highlighting their beauty and the role of calcium carbonate. It explains how calcium carbonate is abundant in nature and used by mollusks to create diverse shell structures. The video delves into the properties of nacre, a strong and iridescent biomaterial, and describes how mollusks use it to form pearls as a defense mechanism against intruders.

What common compound is responsible for the formation of pearls and other marine structures?

• Calcium carbonate

• Silicon dioxide

• Magnesium sulfate

• Sodium chloride

What organ in mollusks is responsible for secreting the organic matrix used in shell formation?

• Gills

• Foot

• Mantle

• Radula

Which crystal structure of calcium carbonate is more stable and less prone to dissolving?

• Aragonite

• Calcite

• Gypsum

• Quartz

What is the special form of aragonite known for its iridescence and strength?

• Jade

• Nacre

• Opal

• Amber

How do mollusks use nacre as a defense mechanism?

• By camouflaging with the environment

• By coating irritants to form pearls

• By forming a hard shell

• By secreting toxins

What is the role of proteins in the formation of nacre?

• They dissolve calcium carbonate

• They provide color to the nacre

• They direct the orientation of aragonite layers

• They harden the shell

What happens when light strikes the multi-layered structure of nacre?

• It absorbs all light

• It reflects a single color

• It creates a cascade of shifting rainbows

• It becomes transparent