Absorption spectrum

Definition

An absorption spectrum is a graph showing the specific wavelengths of light absorbed by a substance, typically pigments like chlorophyll. It highlights which wavelengths are utilized for processes such as photosynthesis.

5 Must Know Facts For Your Next Test

1. The absorption spectrum of chlorophyll shows peaks in the blue (around 430-450 nm) and red (around 640-680 nm) regions.
2. Green light is least absorbed by chlorophyll, which is why plants appear green.
3. Absorption spectra are critical for understanding how different pigments contribute to photosynthesis.
4. The energy from absorbed light wavelengths drives the light-dependent reactions of photosynthesis.
5. Different pigments (chlorophyll a, chlorophyll b, carotenoids) have distinct absorption spectra.

Review Questions

• What colors of light does the absorption spectrum of chlorophyll show the highest absorption?
• Why do leaves appear green based on their absorption spectrum?
• How does the absorption spectrum relate to the efficiency of photosynthesis?

Related terms

Chlorophyll: The primary pigment in plants that absorbs light for photosynthesis.

Carotenoids: Accessory pigments in plants that absorb light in different wavelengths and protect against photo-damage.

Light-dependent Reactions: The first stage of photosynthesis where light energy is converted into chemical energy.