The Question is from neet-botany plant-kingdom phaeophycea, and it was created by the author NISHANTH

Question

Fucoxanthin, a prominent pigment in Phaeophyceae, masks other pigments.  Under which light conditions would chlorophyll a's fluorescence be MOST readily observable in these algae?

NISHANTH · Accepted Answer

## CORE INFORMATION
✓ **Answer**: 3 (Green light)
## CONCEPT FRAMEWORK
 **Primary Concept**: Absorption and fluorescence of pigments in photosynthesis.
 **Related Topics**: Photosynthetic pigments, light absorption spectra, fluorescence spectroscopy.
 **Prerequisites**: Understanding of chlorophyll a's absorption spectrum and the role of accessory pigments.
## SOLUTION PATHWAY
**Given Information**:
  Fucoxanthin masks other pigments in Phaeophyceae (brown algae).
  Chlorophyll a fluorescence needs to be observed.
**Method & Steps**:
 1. Understand pigment absorption:
  Reasoning: Fucoxanthin absorbs strongly in blue and green wavelengths. Chlorophyll a absorbs strongly in red and blue wavelengths, but less so in green.
  Formula/Rule: None explicitly needed; it's based on understanding absorption spectra.
 2. Consider masking effect:
  Working: Since fucoxanthin masks other pigments, the light wavelengths absorbed by fucoxanthin will make it difficult to observe the fluorescence of other pigments. We are interested in chlorophyll a fluorescence.
  Key Point: We want the light condition where fucoxanthin absorbs the least, allowing chlorophyll a's fluorescence to be observed.
 3. Identify optimal light condition:
  Result: Green light is absorbed least by fucoxanthin, thus allowing chlorophyll a's fluorescence to be more readily observable.  
  Verification:  This aligns with the understanding of the absorption spectra of fucoxanthin and chlorophyll a.
 ## OPTION ANALYSIS
A :x: Blue light is strongly absorbed by both fucoxanthin and chlorophyll a, making chlorophyll a's fluorescence less observable.
B :x: Red light is absorbed by chlorophyll a, but the fluorescence signal might be masked by the presence of fucoxanthin.
C ✓: Green light is absorbed less by fucoxanthin and relatively less by chlorophyll a, making chlorophyll a's fluorescence more observable.
D :x: Yellow light is absorbed by fucoxanthin, reducing the observation of chlorophyll a fluorescence.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Ignoring the masking effect of fucoxanthin:  Focusing solely on chlorophyll a's absorption without considering the fucoxanthin's role.
  2.Confusing absorption and fluorescence:  Not understanding that the goal is to minimize fucoxanthin absorption to maximize the observation of chlorophyll a fluorescence.
 **Quick Tips**:
  1.Refer to absorption spectra of fucoxanthin and chlorophyll a to quickly identify the wavelength regions of least overlap.
  2.Remember that the question asks for the condition where chlorophyll a's fluorescence is *most readily observable* implying minimizing the interference from other pigments.

NISHANTH · Answer

Blue light

NISHANTH · Answer

Red light

NISHANTH · Answer

The correct Option is "Green light"

NISHANTH · Answer

Yellow light

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