Photosynthesis Review Worksheet
Part A
Match the terms below with the correct description
Chlorophyll
Chloroplast
Electromagnetic spectrum
Electron transport chain
Grana
Light-dependant reactions
Calvin Cycle
Photon
Photosynthesis
Photosystem
Stroma
Thylakoid
a. ____ Photon _______packet of solar energy
b. Light-dependant reactions
energy-capturing portion of photosynthesis that
takes place in thylakoid membranes of chloroplasts and cannot proceed without
solar energy, it produces ATP and NADPH
c. Chlorophyll
green pigment that absorbs solar energy and is important in
photosynthesis
d. Stroma
large, central compartment in a chloroplast that is fluid
filled and contains enzymes used in photosynthesis
e. Chloroplast
membrane-bounded organelle with chlorophyll –
containing membranous thylakoids; where photosynthesis takes place
f. Photosystem
Photosynthetic unit where solar energy is absorbed and
high-energy electrons are generated; contains a pigment complex and an electron
acceptor
g. ETC
Passage of electrons along a series of carrier molecules
form a higher to a lower energy level; the energy released is used for the synthesis
of ATP.
h. Photosynthesis
Process usually occurring within chloroplasts whereby
chlorophyll traps solar energy and carbon dioxide is reduced to a carbohydrate.
i. Photosystem
Series of reactions in which light is captured to provide the
energy to fix carbon dioxide into glucose in the chloroplast.
j. Calvin cycle
Synthesis portion of photosynthesis that takes place in the
stroma of chloroplasts and does not directly require solar energy; it uses the
products of the light dependant reactions to reduce carbon dioxide to a
carbohydrate
Part B
Answer the following questions
1. Explain the difference between autotrophs and heterotrophs. Give two examples of
each.
Auto – make their own food: plants, cyanobacteria
Hetero – get food from others: people, fish
2. Explain why chloroplasts are green. (use the correct information from the
electromagnetic spectrum)
Red and blue wavelengths are absorbed by pigments allowing green wavelengths to be
reflected which we then see.
3. What is NADPH? What is the difference between NADP+ and NADPH? How does
NADP+ turn into NADPH?
NADPH = electron carrier
NADP+ is empty and oxidized
NADPH is carrying electrons and is reduced
4. Write the chemical equation for the process of photosynthesis.
CO2 + H20 + PHOTON  (CH2O)n + O2 + H2O
5. What are the reactants and products of Light Dependant Reactions? Where in the
chloroplast do they occur?
Reactants: Photon, H2O, Pheophytin,
Products: ATP, NADPH, O2
Location: Thylakoid membrane
6. What are the reactants and products of Light-Independent Reactions? Where in the
chloroplast do they occur?
Reactants: CO2, RuBP
Products: G3P, more RuBP
Location: Stroma
Part C
The Light Dependent Reactions of photosynthesis occur on the thylakoid membranes of
the chloroplast. Below is a diagram that describes the path of the electrons throughout the
L-D reactions. Use it to answer the next set of questions.
1. Describe the first set of Light-Dependant reactions.
Photon splits H2O releasing O & H. Electrons are stripped from H+ and
energized. The energized electrons travel down the ETC and are passed to the
second photosystem.
2. Every time a photon is absorbed in the chlorophyll a 2 electrons are excited. They
are not recycled. Where does the supply of electrons come from and where do
they end up at the end of L-D set of reactions?
From - H20
End up - NADPH
3. What products result specifically from Photosystem I and Photosystem II?
O2, ATP, NADPH
4. When a water molecule is split, what is it split into? Where do all the resulting
components end up?
H+ - stroma
O2 - atmosphere
5. At what steps of L-D reactions is ATP made. What is it specifically used for? (this
will be different depending when and where is it produced)
ETC of Photosystem II
Used to fuel Calvin cycle
6. Describe the action of protein carrier: ATP synthase? Explain why is it important
to build up a Hydrogen ion concentration gradient in order to have it properly
function?
H+ flowing back into the stroma pass through ATP-synthase. The energy
of H+ moving down its concentration gradient provides the power for
ATP-synthase.
Part D
1. What are Light-Independent Reaction often called? Calvin Cycle
2. Why is there a need to go on with Light – Independent reactions? Why not stop
with the Light –Dependant Reactions since ATP and NADPH are energy carrying
molecules?
Energy may need to be stored as carbs rather than used immediately
3. Where does the Carbon Dioxide come from? What will happen to it and what will
it eventually become?
CO2 from atmosphere
Fixed into G3P (eventually complex carbohydrates)