Cell Energy: Photosynthesis

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Cell EnergyPhotosynthesis Respiration

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Biology 4B

• Investigate and Identify cellular processes
  including synthesis of new molecules.

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How are plant animal cells alike different?
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SYNTHESIS Cells Make Molecules

• Cells dont make just anything. They make
  molecules. And the process by which cells make
  molecules is called synthesis
• One important molecule synthesized by plant
  cells is glucose. (Made in chloroplasts)
• Plant and animal cells use glucose as an energy
  source by changing it to ATP (In the mitochondria)

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Todays Learning Goals

• In plants, chlorophyll (found in chloroplasts)
  captures energy from the sun in order to make
  food during photosynthesis
• Cells release energy from food through either
  cellular respiration or fermentation
• Photosynthesis and Cellular Respiration are
  considered to be opposite. They feed each other.

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How Does a Plant Make Its Own Food?

• Plants use carbon dioxide (CO2), water (H2O), and
  suns energy to make food in the form of glucose.
• This is called photosynthesis
• The glucose gives plants energy
• Animals get the
  energy stored in
  
  plants when they
  
  eat them.

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How Do Plants Get Energy From Sun?

• Plants have pigments that absorb energy from
  light
• Chloroplasts are the site of photosynthesis.
  They contain Chlorophyll (the pigment used in
  photosynthesis)

CO2 enters through the stomata O2 exits through
them
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What Food do Plants Make?

• The food plants make is a sugar called glucose
  (C6H12O6).
• Glucose and oxygen (O2) are made during
  photosynthesis.

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How Do Organisms Get Energy From Food?

• Animals cannot make their own food like plants
  can.
• But, BOTH plants and animals must break down
  (digest) food in order to get energy from it (so
  they can live, grow, develop)
• Cells do this 2 ways cellular respiration and
  fermentation

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Cellular Respiration Fermentation

• Cellular Respiration uses oxygen (O2) to break
  down food
• Fermentation does not use oxygen
• Cellular respiration releases more energy from
  food than Fermentation.
• So most eukaryotes
  
  (ex plants animals)
  get
  their energy through
  cellular respiration

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Cellular Respiration
Cells that need a lot of energy contain lots of
mitochondria (Example-heart cells which are
always contacting or sperm cells which are
constantly swimming)

• Cellular Respiration is a chemical process that
  happens in cells
• In prokaryotes, it happens in the cell membranes
• In eukaryotes, like our cells, it happens mostly
  in the mitochondria

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Process of Cellular Respiration

• Food (glucose) is broken down into CO2 and H2O
  and energy is released
• C6H12O6 6 O2 ? 6 CO2 6 H2O energy (ATP)
• This energy can be used for
• Keeping a constant body temperature
• Storage (ATP) - to be used later for things like
  growth

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What Do You Notice?
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Check It Out! Compare Respiration
Photosynthesis

• Did you notice that cellular respiration is just
  the opposite of photosynthesis?

Photosynthesis
Respiration
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Fermentation

• Happens when cells cannot get the oxygen they
  need for cellular respiration
• Fermentation is a way to get energy when oxygen
  isnt available
• Ex In short, fast races you might get a burning
  feeling in you leg muscles because of a build up
  of lactic acid (made during fermentation)

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Pop Quiz

• 1) In respiration cells use oxygen (____) and
  glucose (____) to make energy.
• O2 and C6H12O6 are used to make ATP Energy
• 2) Which organelle carries on cellular
  respiration?
• MITOCHONDRIA
• 3) Do plant or animal cells carry on cellular
  respiration?
• BOTH ANIMAL PLANT CELLS NEED ENERGY
• 4) Do plant or animal cells carry on
  photosynthesis?
• PLANT CELLS BECAUSE ONLY THEY HAVE CHLOROPLASTS
• 5) What is the name for the energy produced by
  mitochondria?
• ATP (Adenosine Triphosphate)

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Pop Quiz

• 6) Plants use carbon dioxide (____), water
  (____), and the suns energy to make
• CO2 and H2O are used to make GLUCOSE C6H12O6
• 7) Which organelle carries on photosynthesis?
• CHLOROPLASTS FOUND ONLY IN PLANT CELLS
• 8) BOTH plants and animals must break down food
  in order to get ________from it.
• ENERGY IN THE FORM OF ATP
• 9) How are respiration and photosynthesis
  related?
• THEY ARE THE REVERSE (OPPOSITE) OF EACH OTHER.
• 10) Fermentation is a way to get energy when
  ______ isnt available. In humans ( )
  acid is produced.
• OXYGEN and LACTIC ACID

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Practice Questions

• Working muscle cells that are deprived of
  oxygen produce
• A. Alcohol
• B. Lactic Acid
• C. Citric Acid
• D. Acetone

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Practice Questions

• Which of these is a characteristic of body
  cells that require large amounts of energy?
• A. They have large number of mitochondria
• B. They have a supplementary Y chromosome
• C. They have a two-layer membrane
• D. They have a storage area for albumin
  proteins.

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Practice Questions

• Why are photosynthesis and cellular
  respiration often considered opposites?
• A. Photosynthesis produces twice as many ATP
  molecules as cellular respiration does
• B. Water is released during photosynthesis and
  consumed during cellular respiration
• C. Photosynthesis occurs during the day and
  cellular respiration occurs at night
• D. Oxygen is produced during photosynthesis
  and used during cellular respiration

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Practice Questions

• Which molecule provides most of the energy
  used to drive reactions in cells?
• A. DNA
• B. RNA
• C. ATP
• D. ADP

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Practice Questions

• Which structure regulates gas exchange during
  the processes of photosynthesis and respiration?
• A. Q
• B. R
• C. S
• D. T

T is pointing to the guard cells which surround
the openings called stomates. The guard cells
open and close.
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• To produce 4 molecules of sugar, a plant
  needs-
• A. 6 molecules of hydrogen
• B. 12 molecules of ATP
• C. 18 molecules of water
• D. 24 molecules of carbon dioxide

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