Photosynthesis and Cellular
Respiration
Chapters 6 and 7
Photosynthesis
• Energy from the sun allows plants to grow
• Animals eat plants, acquire energy from the
plants
• All energy originally from the sun
Photosynthesis
• Two categories of organisms:
– Autotrophs - use energy from sunlight to
make organic compounds.
– Heterotrophs - organisms that must get
energy from food instead of directly from
sunlight
Photosynthesis
• Photosynthesis converts light energy from the
sun into chemical energy in the form of
organic compounds.
Where does photosynthesis occur?
Classwork
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Define and sketch:
Chloroplasts
Thylakoids
Grana
Stroma
Photosynthesis
Photosynthesis
• Photosynthesis can be divided into two stages:
1. Light Reactions – light energy is converted
to chemical energy
2. Calvin Cycle – organic compounds are
formed
Photosynthesis
Glucose (sugar)
Pigments
• Pigments – compounds that absorb light
• Chloroplast pigments:
– Chlorophylls – chlorophyll a is directly involved in
light reactions of photosynthesis
– Carotenoids
Pigments
Light Reactions
• Uses light energy
• Converts light energy to chemical energy
through photosystems
• Makes ATP (energy!) and NADPH
• Converts H2O into O2
• Takes place in the thylakoid membrane of the
chloroplast
Light Reactions
• Photosystem I and Photosystem II
• Moves electrons
The Calvin Cycle
• Does not require light energy
• Uses energy produced in the light reactions
• Produces C6H12O6 (sugar) from CO2 (carbon
dioxide)
Group Work
Chloroplasts
• What is the structure of a chloroplast?
• Where are chloroplasts located?
• What are grana? Thylakoids? Thylakoid membranes?
• Where do the reactions of each stage of photosynthesis
occur?
Products and Reactants of Photosynthesis
• What are the two stages of photosynthesis?
• What are the products and reactants of photosynthesis?
• What are the products and reactants of the light reactions?
• What are the products and reactants of the Calvin Cycle?
Photosynthesis
Includes
Which uses
Which produces
Which uses
Which produces
Cellular Respiration
• Cellular respiration – the complex process in
which cells make ATP by breaking down
organic compounds.
Cellular Respiration
• Both autotrophs and heterotrophs use cellular
respiration.
• The products of cellular respiration are the
reactants in photosynthesis; conversely, the
products of photosynthesis are reactants in
cellular respiration.
Cellular Respiration
• Cellular respiration can be divided into two
stages:
1. Glycolysis
2. Aerobic respiration
Glycolysis
• Takes place in the cytosol of cells.
• One six-carbon glucose molecule is oxidized to
form two three-carbon pyruvic acid
molecules.
• A net yield of two ATP molecules is produced.
Aerobic Respiration
• Second stage of cellular respiration.
• Aerobic respiration takes place in the
mitochondria.
• Can be divided into two steps:
1. Krebs Cycle
2. Electron Transport Chain
Krebs Cycle
• Breaks down Acetyl CoA
(from pyruvic acid) to
produce CO2, hydrogen
atoms, and ATP.
• Occurs in mitochondrial
matrix.
Electron Transport Chain
• Second stage of aerobic
respiration.
• Occurs in inner
mitochondrial membrane.
• Transports electrons to
make LOTS of ATP (38
total for ETC and Krebs)
• Uses oxygen as the final
electron acceptor to
make water.
Electron Transport Chain
A Summary Of Cellular Respiration
Fermentation
• Aerobic respiration can only take place when
oxygen is present.
• When oxygen is not present, fermentation
occurs.
• Two types of fermentation
– Lactic acid
– Alcoholic
Aerobic vs. Anaerobic
Fermentation
Self Quiz/ Classwork
1. What are the products and reactants of cellular
respiration?
2. What types of organisms do cellular respiration?
3. What two main steps can cellular respiration be
broken down into? How can this be broken
down even further?
4. Why is oxygen so important in cellular
respiration? What happens when there is no
oxygen present?
5. How are the products and reactants of
photosynthesis and cellular respiration related?