Quackenworth Life Science Review
PHOTOSYNTHESIS
What is photosynthesis?
Humans and plants alike need nutrients and energy to survive. Humans get food by
eating. Plants get nutrients and energy by a process called photosynthesis.
Photosynthesis is the process by which carbon dioxide (CO2), water (H2O), and
sunlight are converted into oxygen and a sugar called glucose.
OVERVIEW OF PHOTOSYNTHESIS
sunlight
CO2
O2
glucose
H2O
(sugar)
Light combines with H2O and CO2.
A conversion process takes place.
The output of this process is O2 and glucose.
Photosynthesis
Crossword Puzzle
WORD BANK
carbon dioxide
chlorophyll
chloroplast
organelles
glucose
oxygen
photosynthesis
water
Experiment: What happens if a plant is grown without light?
Light and Dark Reactions
Photosythensis takes place in the dark and in the
light. These occurrences are called light and dark
reactions. Stroma and grana play an important
role in both reactions.
LEAF
PLANT CELL
Leaves are made of plant cells. Plant cells
contain organelles called chloroplasts. In the
same fashion, chloroplasts are made of small
parts called grana and stroma. Grana and
stroma are vital to both of these reactions.
CHLOROPLAST
STROMA
CHLOROPHYLL
Grana
1
LIGHT REACTION
The purpose of the light reaction
is to split water (H20) into oxygen
(02). This occurs in the grana.
2
DARK REACTION
The purpose of the dark reaction
is to change CO2 into sugar. This
occurs in the stroma.
Answer the following questions.
1) Photosynthesis takes place in _________________ reactions and __________________
reactions.
2) Name two special parts of the chloroplast and their purposes. ______________________
_______________________________________________________________________
3) What happens during the light reaction? _______________________________________
_______________________________________________________________________
4) What happens during the dark reaction? ______________________________________
_______________________________________________________________________
Chloroplast
The chloroplast is where photosynthesis takes place. In a few
words, chloroplasts are processing machines and are just one
part of the many parts of a plant cell. These parts are sometimes
called organelles. An organelle is part of a plant cell just like your
heart, an organ, is a part of your body.
This leaf is made up of
several plant cells.
LEAF
Plant cells contain several
machines called organelles.
PLANT CELL
CHLOROPLAST
Chloroplasts are organelles.
This is where photosynthesis
takes place.
CHLOROPHYLL
Answer the following questions.
Chlorophyll make up
chloroplasts and is a
substance captures light from
the sun.
1) Where does photosynthesis take place?_______________________________________
2) Plant cells are made up of several machines called ______________________________
3) What is the substance that captures light from the Sun?___________________________
4) Give an example of an organelle. ____________________________________________
_______________________________________________________________________
5) According to the diagram above, what is the leaf made up of?______________________
More on Photosynthesis
There are several steps in the process of photosynthesis. Below is an easy formula
showing the overall process of photosynthesis.
Glucose + Oxygen
Water + Carbon Dioxide + Light
FIRST PART OF PHOTOSYNTHESIS
The first part of photosynthesis is when light and water (H2O) enter the plant.
The water is broken down and oxygen (O2) is released.
1
O2
H2O
Light
2
SECOND PART OF PHOTOSYNTHESIS
In the second part of photosynthesis, a process occurs where CO2
is converted glucose. The actual photosynthesis takes place in the
chloroplast. Chloroplasts are part of a plant cell.
CO2
Chloroplast
Glucose
Storage
Things to remember in part two:
Photosynthesis takes place in the chloroplast.
CO2 is converted into glucose and is stored and, at some
point, is used for energy.
Answer the following questions.
1) Finish the following formula for photosynthesis:
CO2 +________ + _______________
O2 + ____________________
2) Where does photosynthesis take place?_____________________________________
3) What are the two results of photosynthesis?__________________________________
4) What is another name for sugar?___________________________________________
5) What happens to the oxygen that is created by photosynthesis?__________________
_______________________________________________________________________