Transcript PHOTOSYNTHESIS & RESPIRATION

PHOTOSYNTHESIS
I. Autotrophs and Heterotrophs
Energy for living things comes from the SUN
A. Autotrophs- make their own food
• Ex: plants, some bacteria, protists
• Heterotrophs- obtain it from the
foods they consume
» Ex: animals, some bacteria,
protozoans (and even
fungi!)
• Sooo… food as energy is either MADE through
photosynthesis or OBTAINED through
consumption
II. Think about the Location of
Photosynthesis…
= WATER
Other Important Parts
Xylem:
transports
H2O
Stoma:
pore that
allows
gases to
enter and
exit
III. CHLOROPLAST STRUCTURE
A. Double-membrane
structure
1outer membrane
2  inner membrane
3  granum (stack)
4  Thylakoid (individual)
5  Stroma (fluid)
B. Internal Organization
1. Thylakoids:
photosynthetic membranes that
have clusters of chlorophyll and
other pigments
2. Stroma: Fluid surrounding
thylakoids
IV. Light & Pigments
A. Sunlight is “white” but contains mixtures
of visible wavelengths
B. Plants gather sun’s energy using lightabsorbing molecules called PIGMENTS
MAJOR
1. Chlorophyll a
- Absorbs all colors of light
except green
- Plays major role in light
reactions of photosynthesis
2. Chlorophyll b
- Yellow-green
MINOR
C. Plant Pigments
3. Xanthophyll
- In carotenoid family
- Yellow
4. Carotene
- Red & orange pigments
Plant pigments absorb different wavelengths of
energy- which wavelength is the LEAST absorbed?
Green is
NOT
absorbed!
D. Wavelengths
1. Leaves ABSORB blue-violet & red-orange
light very well
2. Green light is REFLECTED why plants
look green!
V. PHOTOSYNTHESIS
Inputs: Light, carbon dioxide, & water
Outputs: sugar and oxygen
Photosynthesis Has Two Parts:
VI. Light Reaction
1. Chlorophyll captures light
energy in chloroplast
2. This splits H2O into oxygen
and hydrogen
3. Oxygen is a "waste product"
& escapes to the
atmosphere
4. Energy from the reaction is
used in the next stage
(Calvin Cycle).
B. ATP and NADPH (chemical energy) are
recycled back into the system.
C. Light reaction is charging up the
“battery” needed to make
sugars in Calvin Cycle
VII. Calvin Cycle
A. Does NOT use light at all
B. This is the process to use
energy from Light Cycle to
convert CO2 into glucose
Reactants:
VIII.Overview of Photosynthesis
Products:
Two Processes
Light Reaction
Calvin Cycle
IX. Factors Affecting Photosynthesis
• Shortage of raw materials
• Temperature
• Light intensity