A spectrum that depicts the magnitude of response of a biological system to light as a function of wavelength is called:
A spectrum that depicts the magnitude of response of a biological system to light as a function of wavelength is called:
Select an option to attempt
Correct Answer: Option A
Explanation
Action spectrum in plant physiology:An action spectrum is a graph that shows the relative effectiveness of different wavelengths of light in causing a specific biological response (photobiological process):• X-axis: wavelength (nm)• Y-axis: relative rate or magnitude of the biological response per unit photon energyApplications:• Photosynthesis action spectrum: peaks in red (~660–680 nm) and blue (~430–450 nm) — identifies chlorophyll a, b as primary pigments.• Photomorphogenesis action spectrum: peaks in red/far-red — identifies phytochromes.• Phototropism action spectrum: peaks in blue/UV-A — identifies phototropins.Distinction:• Absorption spectrum: shows which wavelengths a pigment absorbs (in vitro).• Action spectrum: shows which wavelengths actually DRIVE the biological process (in vivo).If action spectrum matches absorption spectrum → that pigment is responsible for the process.Answer: An action spectrum plots the effectiveness of different light wavelengths in inducing a biological response.