Which Is an Example of an Enzyme Using Substrate Orientation

question 221

Multiple Choice

Which is an example of an enzyme using substrate orientation as a mechanism for lowering the activation energy of a reaction?

• A) Aligning the substrate atoms so they are brought into proximity with each other, favoring the chemical reaction
• B) Altering the hydrophobicity of a substrate (e.g., making a hydrophobic molecule hydrophilic)
• C) Altering the shape of the enzyme to favor expulsion of the product
• D) Aligning two different substrates such that their reactive atoms are held as far apart as possible
• E) Chemically cleaving the substrate so that the small substrate fragments can enter solution more easily

---

Definitions:

Midbrain

A region of the brainstem involved in vision, hearing, motor control, sleep/wake, arousal, and temperature regulation.

Hayflick Limit

Genetically controlled limit, proposed by Hayflick, on the number of times cells can divide in members of a species.

Maximum Life Span

The upper boundary of life expectancy for an organism, representing the greatest age an individual of a species can live under ideal conditions.

Prefrontal Regions

Areas of the frontal lobes of the brain responsible for complex behaviors including decision making, planning, and moderating social behavior.