Photosynthesis Photosynthesis Pigments and Absorption 2

Question 1

Chlorophyll b most strongly absorbs light at which wavelengths?

Accepted Answer

Blue (~453 nm) and orange-red (~642 nm)

Answer

Chlorophyll b absorbs maximally in the blue region near 453 nm and the orange-red region near 642 nm, complementing chlorophyll a's absorption range.

Question 2

Which laboratory technique is commonly used to separate different photosynthetic pigments from a leaf extract?

Accepted Answer

Paper chromatography

Answer

Paper chromatography separates photosynthetic pigments based on their solubility in a solvent and their affinity for the paper, producing distinct colored bands.

Question 3

Which part of the chlorophyll molecule is primarily responsible for absorbing light energy?

Accepted Answer

The porphyrin ring (head) containing magnesium

Answer

The porphyrin ring of chlorophyll contains a central magnesium ion and a conjugated system of double bonds that absorbs photons of light.

Question 4

Phycocyanin is a photosynthetic pigment found primarily in which group of organisms?

Accepted Answer

Cyanobacteria and red algae

Answer

Phycocyanin is a phycobiliprotein pigment characteristic of cyanobacteria and red algae, where it absorbs wavelengths that chlorophyll cannot.

Question 5

What is the role of antenna pigments (light-harvesting complexes) in the photosynthetic process?

Accepted Answer

Absorb photons and funnel the excitation energy to the reaction center

Answer

Antenna pigments form large complexes that capture photons from a broad range of wavelengths and transfer the excitation energy to the reaction center chlorophyll.

Photosynthesis Practice Test

Photosynthesis Practice Test

Photosynthesis Photosynthesis Pigments and Absorption 2