Photosynthetic pigments are the molecules which capture the photons from solar light. This solar energy further transfers to the NADP and ADP and eventually used in the synthesis of glucose. Thus these pigments play vital role in photosynthesis. The uploaded lesson plan is for teaching photosynthetic pigments to the class 11 students (in India). The duration of the class will be 45 minutes. The reference book is NCERT- biology book for class 11 and the unit is 'Photosynthesis in higher plants'.

1. Lesson No: 1 Subject: Biology
Unit: Photosynthesis in higher plants
Class: XI Topic: Pigments involved on photosynthesis Time: 45 minutes
Teaching Points:
• Pigments involved on photosynthesis
Instructional Objectives:
The students will be able to
Knowledge:
• Define photosynthesis
• Label different components of chloroplast
• Recall division of labour in chloroplast
Understanding
• Identify different pigments involved in photosynthesis
Application
• Determine the role of accessory pigments in photosynthesis
Analysis
• Analyse why only light in the visible range of spectra is appropriate for photosynthesis
Teaching Aids:

2. • Chromatographic paper showing already separated photosynthetic pigments
• Power point presentation showing graph of absorption spectrum of chlorophyll a, chlorophyll b and carotenoids
• Power point presentation showing graph of action spectrum of photosynthesis superimposed on absorption spectrum of chlorophyll a
Reference:
• NCERT Biology : Textbook for class XI
Previous knowledge Teachers activity Pupils activity
Structure of chloroplast Teacher asks about: Students reply:
Different components of chloroplast Outer membrane, inner membrane, grana,
thylakoid, stroma, stromal lamella
Where does light reaction take place Thylakoid membrane
Where does dark reaction take place Stroma
As we already know that light is necessary for photosynthesis, there are some pigment molecules located in the thylakoid membrane to capture solar
energy.
Statement of Aim: In today’s class we will be studying about pigments involved in photosynthesis.
CONTENT INSTRUCTIONAL
OBJECTIVES
TEACHTER’S ACTIVITY STUDENT’S ACTIVITY

3. Pigments
involved in
Photosynthesis
Student identifies
different pigments in
photosynthesis
Teacher shows a paper chromatogram with already separated
pigments of spinach leaf
Teacher asks students how many pigments they can observe
Teacher explains the color of the leaves is due to four pigments:
chlorophyll a, chlorophyll b, carotene and xanthophyll
Students observe chromatographic paper
carefully and tell that they can see four
well separated colors.

4. Student explains role
of different pigments
in photosynthesis
Teacher shows a power point presentation of graph showing
absorption spectrum of chlorophyll a, chlorophyll b and carotenoids
Teacher explains that all these pigments absorbs light in the visible
spectrum of light. chlorophyll a absorbs maximum at blue and red
regions and reflect the light of green wavelength
Students observe the graph and take down
notes
Teacher shows a Power point presentation showing graph of action
spectrum of photosynthesis superimposed on absorption spectrum
of chlorophyll a
Teacher asks students what they can apprehend from this picture
Students reply that in this graph they can
observe that the rate of photosynthesis is
maximum at blue and red regions of
spectra where chlorophyll a absorbs at
maximum

5. Teacher explains that we can conclude two things from this figure
1. Rate of photosynthesis is maximum at the wavelengths at
which there is maximum absorption by chlorophyll a,
which shows that chlorophyll a is the primary pigment
associated with photosynthesis
2. Although most of the photosynthesis take place at blue and
red regions of spectrum, some photosynthesis does take
place at the other wavelength of visible spectrum. The
pigments other than chlorophyll a, known as ‘accessory
pigments’ like chlorophyll b and carotenoids also absorbs
light and transfer energy to the chlorophyll a. The
accessory pigments enable a wider range of wavelength to
be utilized for photosynthesis and also protect chlorophyll a
from photo oxidation.
Students listen carefully and note
important points

6. Concluding Statement: In today’s class, we have studied about pigments involved in photosynthesis. In the next class, we will study about light reaction.
Recapitulation and Blackboard Summary:
Recapitulation Blackboard Summary
Pigments involved in photosynthesis
Absorption spectrum of chlorophyll a
Primary pigment is chlorophyll and accessory pigments are carotenoids &
chlorophyll b
Chlorophyll a absorbs maximum at blue and red region of visible spectra
and reflect green light
Evaluation:
Graphs 1 – 4 relate to photosynthesis. Three show the absorption spectra of different photosynthetic pigments, with light absorbance on each y axis. One is the
action spectrum of a plant containing these three pigments, with the rate of photosynthesis on the y axis.
Student analyses that
can plants perform
photosynthesis using
light other than the
visible spectrum
Teacher explains that the ultraviolet light has very high energy
photons which can create free radicles and can
break the chemical bonds. This is detrimental to the plants. On the
other hand, the light from infrared region has very less energy
photons to excite electron from chlorophyll molecules. Only the
light in the visible range of spectra has just the right amount of
energy for photosynthesis to occur.

7. Which letter correctly identifies the four graphs?
absorption spectrum
action spectrum
chlorophyll a chlorophyll b carotenoids
A 1 3 2 4
B 1 4 3 2
C 2 3 1 4
D 2 4 3 1
Home assignment: How do plants photosynthesize in winters when all the leaves fall off?