A-Level BiologyLesson Plan
Photosynthesis
Lesson provided by Margaret Royal
Background
Photosynthesis is usually taught in a superficial way at GCSE. Most students learn only
the basic photosynthesis word equation and the need for chlorophyll as a light absorbing
pigment. The biochemical pathway for the production of glucose from simple raw materials
is more complex and requires a big step up in knowledge for A-Level students.
Boardworks A2 Biology ‘Photosynthesis: The Reaction’
presentation is a useful teaching tool.
It has animations and interactive activities that
enable the students to learn the processes involved in
photosynthesis more effectively.
FREE
sample material
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This sample lesson gives you material to get started
teaching photosynthesis, starting with the basic
structure of the leaf, the plant cell and the
chloroplast, in order to pinpoint the precise
locations of the light and dark reactions.
This lays the foundations for teaching the
biochemical stages of the process.
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Approach
The objectives for this lesson are:
• to consider the overall process of • photosynthesis using the word and chemical
equation
• to review basic leaf structure to understand the
structure of a chloroplast.
Photosynth
esis: The R
eaction, slid
e3
Knowledge of leaf structure at a macro and micro level is essential. This should have been
covered in KS3 and KS4, but some pupils will require revision. The photosynthetic pigments
can be introduced in a later lesson.
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A-Level Biology Lesson Plan
Photosynthesis
The Activity
1. Ask pupils to recall the word equation for
photosynthesis. This can be done individually on
laminated paper with a marker pen so everyone
is given the chance to participate. Boards can
be held up so the answers can be checked
visually.
2. Use slide 2 (free to download) and uncover
just the word equation. Then ask pupils to
write and balance the chemical equation for the
process. Some will be able to recall this from
GCSE but others will only know basic chemical
formulae, and they may need help balancing the
equation. Again, answers from each student can be
checked.
Photosynth
esis: The R
eaction, slid
e5
3. Use slide 2 and uncover the balanced chemical
equation and the rest of the slide, which describes
the products of photosynthesis.
4. Ask pupils to brainstorm three key points
explaining the importance of photosynthesis
to the plant itself, and to other organisms. A
discussion of these points should lead on to
the idea of plants being producers and the
starting points of all food chains and webs.
5. Before going into microscopic detail, revise
Photosynth
esis: The R
the basic structure of a leaf by drawing a simple
eaction, slid
e2
leaf on the board. Draw labelling lines to the
petiole, midrib, lamina and network of veins, leaving
the answers blank and labelling them A to D. Students
should quickly sketch the outline and write the correct
labels for each letter from A to D. After having some thinking time,
students can come to the board to label the diagram.
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A-Level Biology Lesson Plan
Photosynthesis
6. Use slide 3 (free to download) to show how the specialised cells are arranged in the leaf
lamina. If shown on an interactive whiteboard, ask students to draw label lines between
the text and the relevant tissues. Get students to verbally describe the role of each of the
tissue layers before revealing the answers. This is necessary revision of GCSE material.
7. Use slide 4 (free to download) for a quick check on learning. Ask students to identify the
tissue before using the drop-down menu. If they struggle to recall the labels, then supply
the options. These quick interactive tests keep students engaged.
8. Having discussed the role of different tissues in the leaf, it is time to look at the structure
of a chloroplast. Move on to slide 5 (free to download) and, whilst clicking through each
of the diagrams, describe how each part of the chloroplast contributes to photosynthesis,
relating back to its role in the plant cell and the leaf structure. Emphasise that a
chloroplast is an organelle in a plant cell, and that each part of this organelle has a role in
photosynthesis.
Taking it Further
The next lesson should start with recalling the structure of the chloroplast, re-using
slide 5 (free to download). Many students incorrectly label the chloroplast, for example,
by identifying the envelope as the cell membrane, a starch grain as the nucleus, or by
labelling thylakoid membranes as endoplasmic reticulum. It is particularly important to
remind students that the chloroplast is an organelle, not a cell.
Students could then investigate the pigments of photosynthesis by carrying out a
chromatography experiment to separate the chlorophylls and carotenoids. Leaf extracts
from ground spinach give good results, but the leaves of copper beech also give some
interest outcomes (they contain anthocyanins). For homework, students could be asked
to investigate the role of the different pigments and to find out why plants make use of a
range of these rather than simply having one type.
Another appropriate exercise for students to undertake for homework is to investigate the
‘endosymbiontic theory’ and make a brief presentation to the class on their findings.
Outcomes
Students can recall the structure of the leaf and understand that the organelles within the
cells have specific roles in the process of photosynthesis. Students should be able to draw,
label and annotate a chloroplast and understand the role of the different components.
Or
Boardworks Ltd
The Gallery
54 Marston Street
Oxford, OX4 1LF
d
r FREE Sampl
You
eD
r
e
i
sc
t: 0845 0 300 400
f: 0845 0 300 200
[email protected]
www.boardworks.co.uk