Chapter 2: Section 2-1: Photosynthesis What is Photosynthesis?

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Chapter 2 Section 2-1 PhotosynthesisWhat is
Photosynthesis?

• The process by which a cell captures the energy
  in sunlight to make food

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How does Photosynthesis Occur?

• It is a two-stage process
• Capturing the suns energy
• Producing Sugars

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How does a plant capture the suns energy?

• In plants, this process occurs in the leaves and
  other green parts of the plant-where the
  chloroplasts are
• In most plants, leaf cells contain more
  chloroplasts than do cells in other parts of the
  plant

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How does a plant get its green color?

• Pigments -colored chemical compounds that absorb
  light found in the chloroplasts
• The main pigment found in the chloroplasts is
  chlorophyll

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What raw materials does the cell need to produce
sugars?

• The cell needs two raw materials water (H2O) and
  carbon dioxide (CO2)

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How does a plant get these raw materials?

• Water is absorbed through the soil
• Carbon dioxide enters the plant through small
  openings on the undersides of the leaves-called
  stomata

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What powers the reaction of the raw materials?

• The energy captured in the first stage of
  photosynthesis

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What are the products of these reactions?

• Oxygen (O2)
• Sugars, including glucose (C6H12O6)

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What is the Photosynthesis Equation?
Light energy

• 6 CO2 6 H20
  C6H12O6 6 O2
• carbon dioxide water
  glucose
  oxygen
• 6 molecules of carbon dioxide and six molecules
  of water combine and combine in the presence of
  light energy yielding one molecule of glucose and
  six molecules of oxygen
• The arrow is read as yields

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What happens to the sugar produced during
photosynthesis?

• Plant cells use some sugar for food
• Some are converted into other compounds, such as
  cellulose
• Some sugar molecules are stored

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What happens to the oxygen produced during
photosynthesis?

• Most passes out through the stomata and into the
  air

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How does photosynthesis relate to the food cycle?

• Most plants are autotrophs an organism that
  makes their own food
• All their energy originally comes from the sun

Euglena
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What are organisms called that eat plants or
other organisms?

• Heterotrophs an organism that cannot make its
  own food
• Ex Bird,
• Caterpillar

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Section 2-2 RespirationHow do plants store and
release energy?

• During photosynthesis, plants capture the energy
  from sunlight and save it in the form of
  carbohydrates, including sugars and starches
• These carbohydrates are broken down when the cell
  needs energy

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What is Respiration?

• The process by which cells break down simple food
  molecules such as glucose and release the energy
  they contain
• This process is carried out continuously

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What is the respiration equation?

• C6H12O6 6 O2 6 CO2 6 H20 energy
• glucose oxygen carbon water
• dioxide

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What are the two stages of respiration?

• In the cytoplasm glucose molecules are broken
  down into smaller molecules
• In the mitochondria (powerhouse) the small
  molecules are broken down even further. These
  reactions require oxygen and produce a lot of
  energy

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How are photosynthesis and respiration related?

• They can be thought of as opposite processes
  forming a cycle that keeps oxygen and carbon
  dioxide constant in the atmosphere

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How do organisms obtain food if there is no
oxygen available?

• Fermentation an energy releasing process that
  does not require oxygen
• Energy output is lower with fermentation then
  with respiration

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What are the types of fermentation?

• Alcoholic Fermentation alcohol is made when
  organisms break down sugars
• Lactic-acid Fermentation lactic acid is
  produced when there is a lack of oxygen to muscle
  cells muscles will feel weak and sore