A Molecular Ratchet

question 58

Multiple Choice

A molecular ratchet

• A) allows processes to be reversed after they are initiated.
• B) has equal thresholds for activation and inactivation.
• C) is used in synthetic biology but not natural systems.
• D) requires more stimulation to turn itself on than to keep itself on.
• E) is an intrinsic rather than emergent property.

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Definitions:

Optic Chiasma

The X-shaped structure formed by the crossing over of the optic nerves in the brain, which allows visual information from each eye to be processed on both sides of the brain.

Blind Spot

Area in the retina where the axons of the three layers of retinal cells exit the eye to form the optic nerve; insensitive to light.

Fovea

A small depression in the retina of the eye where visual acuity is highest, due to the high concentration of cones and absence of rods.

Saturation

In color theory, saturation refers to the intensity or purity of a color; in psychology, it can relate to the degree of intensity of a feeling or experience.