Plant Parts
Transformations of Matter
Transformations of Energy
Inputs
Outputs
100
What plant part USUALLY absorbs light energy?
a. stems
b. leaves
c. roots
b. leaves
*any green part of a plant may absorb light energy, but most of the work is done by leaves.
100
True or false: when a plant burns, the carbon that was inside the plant's body disappears.
BONUS 100 points: if the correct answer is "FALSE," where does the carbon go? If the correct answer is "TRUE," provide evidence to back up your answer.
FALSE.
Matter cannot be created or destroyed. The C that was in the plant's body ends up in the charcoal and ash, or is released into the atmosphere as CO2 and other C molecules in smoke.
100
The sun and fire both emit 2 forms of energy. What are they?
Light and heat (thermal) energy
100
What we call molecules on the left side (before the arrow) in a chemical equation.
What is reactants?
100
What we call molecules on the right side (after the arrow) in a chemical equation.
What is products?
200
What part of a plant CELL absorbs light energy and converts it to chemical energy through photosynthesis?
chloroplasts
200
Label whether each chemical formula represents an atom or a molecule.
a. C
b. CO2
c. O
d. O2
a. atom
b. molecule
c. atom
d. molecule
200
Chemical energy is stored where?
a. in atoms
b. in chemical bonds
c. in light
b. in chemical bonds
200
What form of energy is an input to photosynthesis? Where do plants usually get this input from?
What is LIGHT energy from the sun
200
Through photosynthesis, energy is transformed from light energy to ___________ energy
What is chemical?
300
What plant part transports glucose and water to where they are needed in the plant?
Veins
300
If a plant needs to store energy for later, what molecule should it make?
Starch is used to store chemical energy for a long time in plants. Glucose also stores energy, but for a shorter time.
300
Does making a chemical bond store or release energy?
Does breaking a chemical bond store or release energy?
Making a chemical bond stores energy.
Breaking a chemical bond releases energy.
300
How many CO2 and H2O molecules are needed to make 1 glucose molecule?
6 CO2 and 6 H2O
300
If a chloroplast has 12 CO2 molecules and 12 H2O molecules, how many glucose and oxygen molecules can it make?
2 glucose and 12 O2
The usual equation is:
6 CO2 + 6 H2O --> C6H12O6 + 6 O2
400
Where is starch usually found in a plant?
Include both parts of a plant CELL, and parts of the plant BODY (e.g. leaves, stems, flowers, etc.)
Starch is stored in organelles inside cells
Starch is most commonly found in seeds, fruits, and sometimes roots (like potatoes)
400
Describe how plants make the strong molecule in cell walls that helps them to stand up straight. Start your explanation with CO2.
First, plants must make glucose by absorbing CO2, H2O, and light energy. They transform light energy into chemical energy by creating chemical bonds to make glucose in photosynthesis. Then, they bond many glucose molecules together to make cellulose, the strong molecule in cell walls that helps them stand up straight.
400
Does glucose or starch contain more chemical energy? Justify your answer.
Starch contains more chemical energy because it is made by bonding multiple glucose molecules together. Chemical energy is stored in chemical bonds, and one starch molecule contains many more energy-rich bonds than a single glucose molecule does.
400
What are the two chemical reactants in photosynthesis, and where do plants get them from?
What is Carbon dioxide (CO2) from the air and H2O (water) absorbed through the roots from the soil?
400
What are the molecular products of photosynthesis, and what does a plant do with them?
Oxygen: released into the atmosphere
Glucose: used for energy or stored as starch or cellulose
500
Where is cellulose usually found in a plant?
Include both parts of a plant CELL, and parts of the plant BODY (e.g. leaves, stems, flowers, etc.)
Cellulose is found in CELL WALLS.
Every plant cell has a cell wall, but cellulose is even more common in rigid parts of the plant like woody stems.
500
Explain what is WRONG in this explanation of how photosynthesis transforms matter and energy:
"In photosynthesis, a plant uses heat energy from the sun to turn carbon into oxygen. The oxygen is released from the plant and the plant keeps the energy."
"In photosynthesis, a plant uses LIGHT energy from the sun to REARRANGE ATOMS IN CO2 AND H2O into O2 and GLUCOSE. The oxygen is released from the plant and the plant keeps CHEMICAL ENERGY IN THE FORM OF GLUCOSE."
500
In order to release the energy in starch, what must happen?
This is a TWO-STEP process!
1) Bonds must be broken to release glucose from the starch
2) Bonds in glucose must be broken to release chemical energy for the plant to use.
500
Which input is most likely to limit the growth of a plant on the forest floor?
Light energy is likely to be limited because it is absorbed by the tree canopy above the forest floor.
500
Would you expect a plant growing on a sunny hillside in a drought, or a plant growing half in the shade near a creek, to contain more chemical energy? Justify your answer.
Answers must reference the idea of limiting factors. The plant in the sun gets plenty of sunlight but is limited by the amount of water it receives. The plant in the shade is limited by sunlight but receives plenty of water. You may argue that either situation is "worse", or more limiting, but you must explain your choice.