Review for Photosynthesis Test
You will be quizzed on the following learning targets. Be sure you can clearly answer each learning
target. Also look at the review sheet for the Matter and Energy Test for additional information.
LT1 - All matter is composed of atoms and atoms combine chemically to form molecules.
a. Define and give examples of atoms and molecules.
b. Distinguish between oxygen air and oxygen atoms.
c. Identify the atoms that are in glucose, water, carbon dioxide, and oxygen gas.
d. Represent atoms and molecules using drawings, chemical formulas, and molecular structures.
LT2 - Matter is conserved in chemical changes, while atoms are rearranged or
In chemical changes, atoms are rearranged, while mass is conserved.
a. Explain how mass is conserved when substances undergo a chemical change.
b. Describe what happens to atoms and molecules during chemical changes.
c. Explain how a balanced equation shows that matter is conserved in a chemical change.
d. Explain how matter is conserved in photosynthesis.
f. Honors: Come up with an example of experimental evidence that would show that plants gain
matter during photosynthesis.
LT3 – Energy is conserved and transformed in chemical changes.
a. Identify various types and forms of energy (e.g. kinetic, potential, chemical, heat, light, etc.)
b. Give examples of high-energy bonds.
c. Describe how energy is conserved during photosynthesis, using the twisty-ties in the Molecule
Models activity as evidence.
d. Honors: Come up with an example of experimental evidence that would show that plants gain
energy during photosynthesis.
LT4 – Organic and Inorganic molecules differ in their bonded atoms.
a. Identify the organic and inorganic molecules in photosynthesis.
b. Describe at least 2 ways to distinguish between or identify organic and inorganic molecules.
LT6 – Describe the transformation of matter in the chemical changes that take place during
photosynthesis using words and/or equations.
a. Write the equation for photosynthesis in 3 different ways: with words, using chemical
formulas, and using molecular structures.
b. Identify the reactants (inputs) and products (outputs) of photosynthesis.
c. Describe what a plant uses glucose, starch, and cellulose for.
d. Name the organelle where photosynthesis takes place.
e. Honors: Write a balanced equation for photosynthesis.
LT7 – Describe the transformation of energy in the chemical changes that take place during
photosynthesis.
a. Identify the types of energy involved in photosynthesis.
b. Explain how photosynthesis can be considered the opposite of burning ethanol, in terms of
energy.
What is Photosynthesis?
If a plant gets hungry, it cannot walk to a local restaurant and buy a slice of pizza. So how does a plant get the
food it needs to survive? Photosynthesis is the process plants use to make their own “food” from the sun's
energy, carbon dioxide and water.
Actually, almost all organisms obtain their energy from photosynthetic organisms. For example, if a bird eats a
caterpillar, then the bird gets the energy that the caterpillar gets from the plants it eats. So the bird is
indirectly getting energy that began with the “food” formed through photosynthesis. Therefore, the process of
photosynthesis is central to sustaining life on Earth.
During photosynthesis, carbon dioxide and water combine with solar energy to create glucose and oxygen.
Glucose is a sugar that acts as the "food" source for plants. Oxygen, which is necessary for animal life, is the
waste of photosynthesis.
The Process of Photosynthesis
Photosynthesis takes place in chloroplasts. Chloroplasts are small structures that can be found inside plant
cells. Think of them as tiny factories where photosynthesis takes place.
The Reactants
What goes into the plant cell? The reactants of photosynthesis are carbon dioxide and water, and the energy
from sunlight. This means that carbon dioxide, water, and the sun's energy are necessary for the chemical
reactions of photosynthesis.
The Products
What is produced by the plant cell? The products of photosynthesis are glucose and oxygen. This means they
are produced at the end of photosynthesis.
• Glucose, the food of plants, can be used to store energy for later in the form of carbohydrate molecules.
• Oxygen is a plant waste product. It is released into the atmosphere through the stomata. As you know,
animals need oxygen to live. Without photosynthetic organisms like plants, there would not be enough
oxygen in the atmosphere for animals to survive.
• In photosynthesis, the plant goes through a series of steps to take carbon dioxide and water, re-arrange the
atoms, and produce glucose and oxygen. The plant uses energy from the sun to break apart carbon
dioxide and water. It then uses the pieces (atoms) and re-arranges them to make glucose and oxygen.
How Do Plants Store Energy?
Glucose is a product of photosynthesis. When plants make more glucose than they can use immediately, they
store the extra glucose as starch. Starch molecules contain many, many glucose molecules. Therefore, starch
is a molecule that can store a great deal of energy for a plant.
Equation for Photosynthesis
The process of photosynthesis can be summarized in a chemical equation that shows the reactants and the
products.
6CO2 + 6H2O + energy  C6H12O6 + 6O2
Additional resources can be found on the class website:
www.sciencewithmswang.weebly.com