Science 7You will need your

books today!

Come Prepared

Science 7 – Feb 21, 2008

• Cellular Energy• Photosynthesis and Respiration

• Two Day Lesson Includes, Bookwork, Notes, and illustration

• Day 1 Notes + book questions• Day 2 Work Day (Book Questions /

Illustration/ Pull it all together)

Announcements

• Congrats to 7th Grade Boys BB for being district champs!

YSBAT• Understand how cells get their energy• Explain in your own words what photosynthesis

means• Write the “ingredients” and “final products” of

photosynthesis in words and chemical formulas• Define RESPIRATION• Illustrate the cycle in which ENERGY flows

between plants and animals in nature

Cells - Energy

Question of the day1. What organelle is responsible for providing

energy in a plant? In an animal Cell?

2. What is the original source of energy on Earth?

3. Hypothesize: What is needed for a plant to grow? (think cellular level)

Photosynthesis and RespirationKey Information

• The Sun provides the Earth with vital energy

• Plants use this energy, along with other necessary ingredients, to grow

• Process of converting sunlight to cell energy is called PHOTOSYNTHESIS

Photosynthesis

• “Photo” means light• Synthesis means to “put together”

Photosynthesis – Key Ingredients

Four Ingredients Needed:• Energy from Sun• Chloroplasts are needed to “Capture” the

sun’s energy • Chlorophyll is the pigment • Stomata Opening on bottom of leaf (allows gas

in and out)• Water• Carbon Dioxide

Pictures of Stomata

Final Products• Two end Products

• Sugar = food for plant• Oxygen

Gases in the Gases in the AtmosphereAtmosphere Oxygen makes up 21% of the air we breathe. Oxygen makes up 21% of the air we breathe.

Nitrogen makes up 78 % of the air we breathe. Nitrogen makes up 78 % of the air we breathe.

Carbon dioxide makes up 0.03% of the Carbon dioxide makes up 0.03% of the atmosphere. Plants are limited in how fast atmosphere. Plants are limited in how fast they can grow by how much carbon dioxide is they can grow by how much carbon dioxide is available to them. available to them.

So, what happens to plants when humans So, what happens to plants when humans increase the amount of COincrease the amount of CO22 in the atmosphere? in the atmosphere?

What are the three major reasons the What are the three major reasons the atmospheric COatmospheric CO22 is on the rise? is on the rise?

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More People, increasing population More Domesticated Ani

malsMore Industrial Gases

What is Sugar used forWhat is Sugar used for??

About half of the sugar About half of the sugar the plant produces is the plant produces is respired by the plant respired by the plant during cellular during cellular respiration to produce respiration to produce ATP’s of energy. ATP’s of energy.

The other half goes into The other half goes into building plant tissues building plant tissues such as flowers, leaves, such as flowers, leaves, stems, roots, seeds, and stems, roots, seeds, and fruit. fruit.

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Equation in WordsWater + Carbon Dioxide + Sun + Chloroplasts Sugar + Oxygen

In Chemical Formula Format:

H20 + CO2 (along with Chloroplasts and Sun) C6H12O6 + O2

• Think Chemistry – Is this recipe right?• Nope: To make it right… you need different

amounts

Balanced Equation

• What you need to make it work:

• 6 H20 + 6 CO2 (along with Chloroplasts and Sun)

C6H12O6 + 6 O2

This means you need 6 waters and 6 carbon dioxides to make 1 sugar and 6 oxygen molecules

PHOTOSYNTHESIS is a CHEMICAL REACTION!!

• CO2 enters through the leaves and O2 is released through the leaves.

• H2O is taken in through the roots.

• What are the reactants of the chemical reaction photosynthesis?

• What are the products?

The Importance of Photosynthesis.

1.Plants are autotrophs, which means they make their own food, by using the energy from the sun.

2.Heterotrophs are organisms that cannot make their own food and have to rely on autotrophs and other heterotrophs for food.

The Importance of Photosynthesis.

3. Nearly all living things obtain energy either directly or indirectly from the energy of sunlight captured during photosynthesis.

4. Photosynthesis also removes carbon dioxide from the air and produces the oxygen that most organisms need to survive.

To sum up photosynthesis…The primary energy source

for all life on earth is the solar energy that the Sun emits.

Nuclear Fusion reactions in the sun release energy. This energy reaches the surface of the earth as the electromagnetic spectrum of energy.

Plants then capture this energy and convert it to an energy source that other organisms can use.

III. Respiration

Respiration

• Respiration is a process that converts Sugars to ENERGY!

• Eating plants (sugars) provides this for animals

• Ingredients• Sugar + Oxygen

• End Products• Carbon Dioxide + H2O + ENERGY!

Chemical Recipe for Respiration

C6H12O6 + 6 O2 6 H20 + 6 CO2 + ENERGY!!

Cycle

The Cycle

Product of Photosynthesis

Sugars and Oxygen

Respiration

Product of Respiration

Water and Carbon Dioxide

Energy from Sun Photosynthesis

Carbon – oxygen cycle

Respiration compared to Photosynthesis

1. Respiration is the process by which organisms break down food to release energy.

2. When organisms breathe, the oxygen taken into the body is used to break down stored sugars to release energy. C6H12O6 + 6O2 6H2O + 6CO2

3. Photosynthesis and respiration are opposite processes in a cycle that keeps the levels of oxygen and carbon dioxide fairly constant.

Importance of Respiration

1. All cells need to respire in order to use the stored energy for all cellular processes, including building and repairing tissues and organs.

2. Plant cells also respire in order to use the energy, from the food they made during photosynthesis, in order to grow and reproduce.

Problems from Book

• Section 1 Assessment Questions (page 48)

# 1c, #2 a,b,c (details needed)

• Job Qualifications – Writing –(Complete Paragraph)

• Section 2 Assessment• Problems #1a,b,c,d and #2 a,b,c

Illustrate the Process• Develop a Poster that represents the

Photosynthesis and Respiration Cycle• Criteria:

• Show the connection between the Sun, plants and animals.

• Include names and Chemical formulas for each “ingredient” or “product”

• Properly “Name” each step of the process• Include how many of each “part” are required to

make the process work• Label what part of the cell is responsible for helping

with this process (e.g. animals Mitochondria, plants ?)

Photosynthesis/ Respiration Mini-packet Expectations

• Title Page with Name, Period, Date• Notes from Class on Photosynthesis and

Respiration (clearly labeled)• Book Questions

• Section 1 (page 48) # 1c, #2 a,b,c (details needed)• Job Qualifications – Writing –(Complete Paragraph)

• Section 2 (#1a,b,c,d and #2 a,b,c)

• crossword