Name: ________________________________________
Modified from http://betterlesson.com/document/367345/l11-hw-photosynthesis-docx
In the spring and summer you will notice that the leaves on trees are green. This is because
photosynthesis is taking place. In order for photosynthesis to occur, the leaf takes in certain
materials that will help with the process. A plant needs to take a gas from the air called carbon
dioxide. Carbon dioxide comes from animals when they breathe. Plants also need water,
which they get from their roots taking it out of the ground. The third thing that a plant needs to
start photosynthesis is the light from the sun.
Plants capture light energy and make their own food using it. The process of photosynthesis is
what allows the plants to make their own food. Photosynthesis allows the chlorophyll inside
each leaf to capture energy. The captured energy is used to build carbohydrates from simple
raw materials (water, carbon dioxide, and minerals). These carbohydrates, also known as
sugar, are a plant’s food. The plant uses some of the sugar, but also stores some. Photosynthesis
also needs to following raw materials to function: carbon, oxygen, and hydrogen. Animals
breathe out carbon dioxide, so this gives the plants oxygen and carbon. Plants receive the
hydrogen through water. The materials enter the plant either at the roots or the leaves.
Inside the leaf there is chlorophyll. This chlorophyll is what captures the sun’s light. Chlorophyll is
also what gives the leaves a green color. The sunlight is converted into chemical energy which
is necessary to continue the process of photosynthesis. When this chemical energy is
introduced to the carbon dioxide and the water, glucose (sugar) and oxygen are created. A
very simple way to put this is:
Carbon dioxide + Water + Chlorophyll and Sunlight = Oxygen + Sugar
There are different parts of the leaf that make this process possible. There are stomata, which
are pores on the underside of leaves. These pores let air enter the leaf and then at night the
pores release oxygen and they allow for water to evaporate. The chlorophyll is what gives the
plants their green color. Chlorophyll is found in the cells of the plants inside chloroplasts. A
chloroplast is like a home for chlorophyll.
Please answer the following questions below
1. What three things must a plant take in to help with the process of photosynthesis?
_______sunlight_____________________________________________________________________
_______water_______________________________________________________________________
_______carbon dioxide_____________________________________________________
2. Where does photosynthesis take place?
_____leaf______________chloroplast_________________________________________________
3. What type of energy conversion occurs in photosynthesis?
_______sunlight -> chemical______________________________________________________
4. What is the formula for photosynthesis?
____carbon dioxide + water + sunlight -> glucose + oxygen____________________________
Circle the reactants and box the products
5. What two things can plants do with the sugars they make?
_______use it and store it_______________________________________________
___________________________________________________________________________________
6. What do the pores in the stomata do?
_________openings that release oxygen and water___________________________
___________________________________________________________________________________
7. Why are plants green?
____________the green pigment chlorophyll___________________________________
8. The formula animals use to get energy is
Oxygen + Sugar -> Carbon Dioxide + Water + Energy
How is this similar to the formula for photosynthesis?
________________opposite processes_____________________________________
___________________________________________________________________________________
9. How is this different from the formula for photosynthesis?
______photosynthesis = light energy -> chemical energy_____________________
_______cellular respiration = glucose -> ATP_________________________________
Respiration
All cells require energy. ATP is the most convenient form of energy in cells, so cells transfer
energy from other molecules into ATP. They do this through glycolysis, fermentation, and
cellular respiration. For this process to happen, we need glucose (as a food source), and
oxygen (from the air)
The first step of energy transformations is called glycolysis. Glycolysis happens in the
cytoplasm of all cells. It takes a molecule of glucose and breaks it in half. When glucose is
broken in half, the cell gains 2 molecules of ATP.
These three carbon molecules (called pyruvate) have a choice for what they can do next.
If there is no oxygen in the cell, then the cells go through fermentation. There are two
different types of fermentation: lactic acid fermentation and alcoholic fermentation. Lactic
acid fermentation makes lactic acid, and it is used to produce food items such as yogurt
and sauerkraut. Alcoholic fermentation makes alcohol and the gas carbon dioxide (CO2),
and it is used to produce items such as beer, wine, and bread.
If oxygen is present in the cell, then the carbon molecules move into the mitochondrion.
Then, they go through the Kreb’s cycle. These pyruvate molecules break down further,
mostly releasing CO2. You then get rid of the CO2 whenever you breathe out. After the
Kreb’s cycle, the carbon leftovers go through an electron transport chain. Oxygen is used
to help release water and lots of ATP. The full formula for cellular respiration looks like this
Glucose + Oxygen = Carbon Dioxide + Water + ATP
Please answer the following questions below.
1. What materials are needed for the process of cellular respiration to happen?
____________glucose and oxygen___________________________________
______________performed by plants and animals____________________________
2. Where does the glucose come from?
_______________plants_____________________________________________________
3. Where does the oxygen come from?
_______________breathed in from air – cannot be stored____________________
4. What happens during glycolysis?
_____________first step, glucose is broken into pyruvate, creates 2 ATP, splits glucose_____
____________________________________________________________________________________
5. The presence or absence of __oxygen_______ determines what the cell does next.
(Fermentation OR Aerobic respiration???)
6. What are the two different types of fermentation?
____________alcoholic and lactic acid_________________________________
____________________________________________________________________________________
7. Where is CO2 produced?
_________Kreb’s cycle in mitochondria________________________________________
8. Where are the water and ATP produced?
___________Electron Transport Chain in Mitochondria_________________________
9. In the space below, copy down the full reaction for cellular respiration
glucose + oxygen -> carbon dioxide + water + ATP
Circle the reactants and box the products
10. How does the reaction above compare to the reaction for photosynthesis?
_______opposite reactant and products________________________________
_______(Energy takes different form—Light Energy/ATP) ________________
Making connections
11. Where do plants get the glucose they need for cellular respiration?
_______________stored from photosynthesis___________________________
____________________________________________________________________________________