Question

Maximum absorption of light by chlorophyll a occurs in which regions of the
absorption spectrum
(a) Blue (b) Red (c) Green (d) Yellow
A. a and b only
B. b and c only
C. a and d only
D. b and d only

Answer 1

Chloroplasts are organelles that conduct photosynthesis, in the photosynthetic process chlorophyll captures the energy from sunlight then converts it and stores it. In simple words, chloroplasts are organelles of the plant cell that convert light energy captured from the sun into chemical energy by the photosynthetic process.

Complete answer:
The set of wavelengths that are absorbed by a pigment it called its
absorption spectrum. The absorption spectrum of chlorophylls is indicated by their peak levels
around 450-470nm and 650-675nm. Chlorophyll a absorb slight different wavelengths than
chlorophyll b.

Option A- a and b only- It says that Blue and Red region only. This is correct option as
photosynthetically active radiation contains wavelength of 400-700nm so, this is wavelength of
blue and red regions hence, this is the correct option.
Option B- b and c only: Red and Green is not correct answer as these wavelength doesn’t lie
under photosynthetically active radiation.
Option C- a and d only: Yellow region doesn’t have maximum absorption of light by chlorophyll a.
Option D- b and d only: Again not the correct answer as yellow is not maximum light absorbing
region by chlorophylls.

So the correct answer is Option A- a and b only.

Note: The thylakoid contain all the chlorophyll that is required by the plant for the process of
photosynthesis. These thylakoids are arranged in stacks called as grana and unstacked regions
are called stroma thylakoids. Grana are interconnected to each other by fret lamellae.