Grade 8 Science Related Reading/Life Science
Grade 8 Life Science
9L.4: Photosynthesis
Task 1 - Pre- Reading Activity
Complete the graphic organizer by writing needs and products of Photosynthesis
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Grade 8 Science Related Reading/Life Science
Task 2 – Reading Activity
What Is Photosynthesis?
Many organisms, including humans, have to eat to get
energy. Plants, however, are able to make their own food.
Plants make their food by a process called photosynthesis.
During photosynthesis, plants use carbon dioxide, water,
and energy from sunlight to make sugars.
How Do Plants Get Energy from Sunlight?
Plant cells have organelles called chloroplasts.
Chloroplasts capture the energy from sunlight. Inside
a chloroplast, membranes called grana contain chlorophyll.
Chlorophyll is a green pigment that absorbs light
energy. Many plants look green because chlorophyll
reflects the green wavelengths of light.
How Do Plants Make Sugar?
During photosynthesis, plants take in water and carbon
dioxide and absorb light energy. Plants use the light
energy captured by chlorophyll to help form glucose
molecules.Glucose is the sugar that plants use for food. In
addition to producing sugar, plants give off oxygen during
photosynthesis.The following chemical equation summarizes
photosynthesis:
As you read, outline
the steps of photosynthesis
in your notebook.
Use the questions in the
section titles to help you
make your outline.
How Does a Plant Take in the Gases It Needs?
Plants take in carbon dioxide and give off oxygen. These gases move into and out of the leaf
through openings called stomata (singular, stoma). Stomata allow gases to move through the
plant’s cuticle, the waxy layer that prevents water loss. Each stoma is surrounded by two guard
cells. The guard cells act like double doors by opening and closing a stoma.
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Grade 8 Science Related Reading/Life Science
A Change in Leaf Color
By: Emily Sohn
Every autumn, leaves begin to change color from a summery green
to spectacular shades of red, orange, yellow, and purple.
Only few people know what makes many plants blush in the autumn. Research has shown that
leaves change color when their food-making processes shut off. The chemical chlorophyll,
which gives leaves their green color, breaks down. This allows other leaf pigments—yellow and
orange—to become visible. But “there’s still a lot we don’t know about this.
It isn’t clear, for example, why different species of plants turn different colors. Or why some
trees become redder than others, even when they’re standing right next to each other.
Food factory
In summer, when a plant is green, its leaves contain the pigment chlorophyll, which absorbs all
colors of sunlight except green. We see the reflected green light.
The plant uses the energy it absorbs from the sun to turn carbon dioxide and water into sugars
(food) and oxygen (waste). The process is called photosynthesis.
As days get shorter and colder in the autumn, chlorophyll molecules break down. Leaves
quickly lose their green color. Some leaves begin to look yellow or orange because they still
contain pigments called carotenoids. One such pigment, carotene, gives carrots their brightorange color. But red is special. This brilliant color appears only because the leaves of some
plants, including maples, actually produce new pigments, called anthocyanins.
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Grade 8 Science Related Reading/Life Science
Task 3 – Post Reading Activity
Vocabulary check! – MAKE SURE YOU KNOW THE WORDS IN BOLD USE A DICTIONARY IF YOU
HAVE TO!
Words in bold
Definition
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Q1: Explain why does chlorophyll look green?
_________________________________________________________________________________
_________________________________________________________________________________
Q2: Predict what do you think would happen if a plant had no stomata?
_________________________________________________________________________________
_________________________________________________________________________________
Q3: What are two products of photosynthesis?
__________________________________________________________________________________
__________________________________________________________________________________
Q4: Where is chlorophyll found in a plant cell?
__________________________________________________________________________________
__________________________________________________________________________________
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Grade 8 Science Related Reading/Life Science
Q5: Explain why are photosynthetic organisms, such as plants, so important to life on Earth?
_________________________________________________________________________________
_________________________________________________________________________________
Q6: Explain if plants need to take in carbon dioxide, why don’t they keep their stomata open all
the time?
_________________________________________________________________________________
_________________________________________________________________________________
Q7: Choose the best answer:
1. Which gas is needed by plants?
a. oxygen
b.nitrogen
c. carbon dioxide
d. other gases
2. What is the process by which plants make their own food?
a. sugar
b.glucose
c. carbon dioxide
d. photosynthesis
3. What is the green pigment in plants called?
a. grana
b.chloroplast
c. chlorophyll
d.cell
4. Which of the following is a byproduct of photosynthesis?
a. nitrogen
b. oxygen
c. helium
d. hydrogen
5. What happens during photosynthesis?
a. Plants store light energy as chemical energy.
b. Plants lose their leaves.
c. Plants store chemical energy as light energy.
d. Plants often die.
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Grade 8 Science Related Reading/Life Science
Q8: Read the words in the box. Read the sentences. Fill in each blank with the word or phrase
that best completes the sentence.
Glucose
chlorophyll
starch
oxygen
1. The light energy captured by chlorophyll is used during photosynthesis to produce
___________________________.
2. The gas given off during photosynthesis is ___________________________.
3. The pigment in plants that absorbs light energy is called ______________________
4.Excess glucose is converted to another type of sugar called __________________
Q9: Refer to the text and explain why leaves change color in autumn?
_______________________________________________________________________________
_______________________________________________________________________________
______________________________________________________________________________
Q10: Match the correct description with the correct term. Write the letter in the space provided .
_____ 1. the process by which plants make their
own food
a. glucose
_____ 2. green pigment found in plant cells that
capture energy from sunlight
b. carbon dioxide
_____ 3. gas is needed by plants for
photosynthesis
d. chlorophyll
_____ 4. an opening in the leaf’s epidermis and
cuticle
c. stoma
e. photosynthesis
_____ 5. the product of photosynthesis
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