We Use Soap to Clean Ourselves Better Than We Could

question 28

Multiple Choice

We use soap to clean ourselves better than we could with water alone.Soaps contain phospholipids that are responsible for the cleansing action.Which of the following statements is the most likely explanation for how soaps work?

• A) Phospholipids are ions and therefore mix with both the water and oily dirt.
• B) Phospholipids are completely hydrophilic and, therefore, oily dirt takes the place of the phospholipid molecules that would be dissolved in the rinse water.
• C) The phospholipid tail attaches to the oily dirt, while the phospholipid head interacts with the rinse water and carries the dirt (and soap) away with it.
• D) The nonpolar fatty acid chains that make up the heads of the phospholipid are hydrophilic, and thus are repelled by the water.

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Definitions:

Cerebellum

A part of the brain located at the back of the skull, vital for coordinating movement and maintaining balance.

Reticular Formation

A network of neurons located in the brainstem, involved in various functions including regulation of wakefulness and sleep.

Midbrain

A central part of the brainstem that plays an important role in vision, hearing, motor control, sleep/wake, arousal, and temperature regulation.

Medulla

The base of the brainstem; it controls vital life-sustaining functions like heartbeat, breathing, blood pressure, and digestion.