62. A spectrum that depicts the magnitude of response of a biological system to light as a function
of wavelength is called:
A. Action spectrum
B. Absorption spectrum
C. Visible spectrum
D. Hypothetical spectrum

Introduction:

In biological systems, light plays a crucial role in processes like photosynthesis and photoreception. Understanding how organisms respond to light at different wavelengths is essential in fields such as plant biology, vision science, and environmental biology. One important concept in this area is the action spectrum, which shows the biological response of a system as a function of light wavelength.

What Is an Action Spectrum?

An action spectrum is a graphical representation that plots the biological response of a system to different wavelengths of light. It highlights which wavelengths are most effective in producing a particular biological outcome, such as the rate of photosynthesis in plants or the activation of photoreceptors in the eyes.

In simple terms, the action spectrum measures how effective light of different wavelengths is in driving a biological process. For example, in plants, the action spectrum of photosynthesis shows which parts of the light spectrum—such as blue or red light—are most efficiently used by chlorophyll for energy conversion.

How Does It Differ From Other Spectra?

There are several types of spectra related to light and biological systems, including:

• Absorption Spectrum: Shows the amount of light absorbed by a substance at different wavelengths. In plants, this would indicate how much light chlorophyll absorbs for photosynthesis.

• Visible Spectrum: Refers to the range of wavelengths of light that are visible to the human eye, typically between 400 and 700 nm.

• Hypothetical Spectrum: This is not a commonly recognized term in the study of light and biology.

The Importance of Action Spectrum

The action spectrum is crucial for understanding which wavelengths of light are most effective in driving specific biological processes. For instance:

• In photosynthesis, the action spectrum helps determine which colors of light are most useful to plants for maximizing energy production.

• In vision, the action spectrum of the retina shows which wavelengths of light stimulate photoreceptor cells, contributing to our ability to perceive light.

Conclusion:

The correct answer to the question is A. Action spectrum, as it specifically measures the biological response to light at various wavelengths.

Answer:

A. Action spectrum