Introduction to Photosynthesis—Online Notes
Visit http://www.phschool.com/science/biology_place/biocoach/photosynth/intro.html and proceed through the
Photosynthesis—BioCoach Activity to complete this noteguide.
***Some questions may require you to use your textbook (pgs.***
An Overview of Photosynthesis
Photosynthesis converts _______________ energy into the _________________energy of _____________ and other
organic compounds. This process consists of a series of chemical reactions that require ______________________ (CO2)
and _______________ (H2O) and store _______________ energy in the form of _______________. _____________
energy from the sun drives the reactions. __________________ (O2) is a _________________ of photosynthesis and is
____________________ into the ______________________.
Write the equation which summarizes photosynthesis:
Photosynthesis transfers ___________________from __________________ to energy-poor CO2 molecules, forming
energy-rich ____________________ molecules. This electron transfer is an example of an
______________________________ process: the _______________is oxidized (_____________________) and the
_______ is reduced (______________________). Photosynthesis uses light energy to drive the electrons from water to
their more energetic states in the sugar products, thus converting solar energy into chemical energy.
Label the diagram below:
Extension Question (use textbook, p. 113):
1. What do you call the organisms that are able to make their own energy (food) through photosynthesis or by breaking
down chemical bonds?
2. What do you call the organisms that must obtain their energy by consuming other organisms?
Electromagnetic Energy
The solar energy called ____________________________ drives photosynthesis. Solar radiation is composed of
_______________________ energy that travels through space in a manner analogous to the motion of ___________ in
water. The distance between the ______________ of waves is called the __________________. The ____________ the
___________________, the ____________ the _____________ for each unit (photon) of electromagnetic energy.
__________________ cannot be created or destroyed. When light is _________________ by a green plant, a small
portion of that energy is __________________ into chemical energy in the process of photosynthesis.
The Action Spectrum for Photosynthesis
A classic experiment reveals which _________________________work best for photosynthesis. The ______________
molecules (chlorophyll) in photosynthetic organisms ________________ specific __________________of light. In 1883,
Thomas Engelmann devised an experiment to learn which _____________________ (__________) of light were the most
effective in carrying out photosynthesis in the green alga ______________________.
Extension Questions:
3. Which are the wavelengths (state the colors) of light that work best for photosynthesis, based on the graph of oxygen
released by the Spirogyra?
4. Which wavelengths of light (state the colors) are absorbed by chlorophyll (used for photosynthesis)? Which wavelength
(state the color) is transmitted by chlorophyll (color of the leaf that is visible to the human eye)?
Read over the Structure of a Leaf and Structure of a Mesophyll Cell sections.
Chloroplast Structure
__________________________ are the sites of ____________________. These double-membrane bound organelles
enclose additional membranes called _____________________. The disc-shaped ___________________ possess an
interior space. The thylakoids are stacked to form _________________, which are suspended in the ______________ of
the chloroplasts.
Color and label the diagram of the chloroplast below (you may use your textbook to help you):
Extension Question (use textbook):
In which part of the chloroplast does photosynthesis
occur?
Chlorophyll
___________________ molecules embedded in the
_______________ membrane absorb ___________
energy. These molecules are the most important
__________________ for __________________ the light
energy used in photosynthesis.
Extension Questions (use textbook):
5. What are the two types of chlorophyll that absorb light energy for photosynthesis?
6. What are the different wavelengths of light absorbed by these two types of chlorophyll? How do these correspond with
the wavelengths of light in Engelmann’s experiment in 1883?
Cooperation of the Light Reactions and the Calvin Cycle
Photosynthesis depends on an interaction between two sets of reactions: the _________________________ and the
_______________________. ______________________ and the other molecules responsible for the light reactions are
built into the_________________ membranes. The enzymes that catalyze the Calvin cycle are located in the
__________________.
Beginning with the ____________________ of light by ______________________, the light reactions convert
___________energy into _______________ energy in the form of ___________and _____________. The ATP provides
the _____________, and the NADPH supplies the _________________ for the ______________________, which
converts _____________________ to ______________. The ADP and NADP+ that result from the
___________________ shuttle back to the _____________________, which regenerate _________________ and
____________________.
Complete the diagram below:
Extension Questions (Click on “A Closer Look”, in the top right corner of your brower window):
Step 1-Light Reaction:
7. What are the two pieces of “equipment” in the thylakoid membrane used to produce ATP and NADPH from light
energy in the light reaction?
8. Where does the energy absorbed from light initiate a transfer of electrons to other molecules?
Step 2-Dark Reaction (The Calvin Cycle):
The Calvin cycle uses _______________ and _________________ to convert _____________ molecules of CO2 to
______________molecule of a ____-carbon sugar. The plant can then use this small sugar to make
___________________ such as glucose and many other organic compounds. The main role of the _______________
_____________ is to restock the stroma with the _________ and ________________ required for the Calvin cycle.
Introduction to Photosynthesis—BioCoach Self Quiz
Score:
/24
Answer the questions on the BioCoach self quiz. You only need to answer the questions listed below (the other questions
are important, but not directly related to our objectives). If you get the question wrong, put an X over that number.
Write out the correct answers (DON’T use just letters). At the end of the quiz, record your score—your score will be out
of 24. Raise your hand to show the teacher your score to get full credit for completing the self-quiz.
3. Most of the carbon dioxide used in photosynthesis is derived from the ______the atmosphere.
4. If photosynthesis on this planet were to stop____________________________________________________________
_________________________________________________________________________________________________.
5. Which of the following is not required for photosynthesis?
6. Which part of the leaf is most active during photosynthesis?
11. The conversion of light energy into chemical energy takes place in _______________________________.
12. The products of the light reaction of photosynthesis are___________________________________
13. The most efficient wavelengths of light for photosynthesis are__________________________.
15. Oxygen released during photosynthesis comes from _____________________.
16. During photosynthesis, what is incorporated into existing organic molecules to build carbohydrates?
17. ATP __________________________________________________________________________________________
19. Light reactions of photosynthesis cannot occur in the absence of ______________________________________.
25. During photosynthesis, electrons extracted from ____________ during the light reactions eventually turn up in
______________made during the Calvin Cycle. These electrons are transferred from the light reactions to the Calvin
Cycle by ___________.