Transcript For Chap 9 Biology Photosynthesis

Chapter 9
Energy in a Cell—Overall Objectives
• Describe the Light and Dark stages of photosynthesis
• Light Spectrum; V.L.S.; ROYGBIV; why is chlorophyll green;
• Know order, which end of VLS is higher energy and shorter
wavelength.
• Why organisms need energy.
• Know general formula for photosynthesis
• What is ATP?
9.1:THE NEED FOR
ENERGY
Energy Needs
• Necessary for work
Kinds of work your body does:
mechanical
chemical
electrochemical shuttling
Where the energy comes from
• Stored in chemical bonds
• Convert the food we eat
• Into:
– ATP
• A form of stored energy
• Short-term energy storage
• “the energy currency of
the cell”
Energy
Sources
•The main sources of ATP
are the major energy
reactions of:
•photosynthesis
•and
ATP –Energy Currency
•
Energy Relationships
large energy-rich molecules
(fats, complex carbohydrates,
proteins, nucleic acids)
ADP + Pi
BIOSYNTHETIC PATHWAYS
(ANABOLIC)
DEGRADATIVE PATHWAYS
(CATABOLIC)
ATP
energy-poor products
(such as carbon dioxide, water)
ENERGY INPUT
simple organic compounds
(simple sugars, amino acids,
fatty acids, nucleotides)
Energy Flow in the Living
World
•All living org. need energy.
•Get energy from breaking down
food.
•Photosynthesis: Light energy used
to build sugars and other organic
molecules from inorganic
molecules. Plants, Algae (protists),
some Bacteria.
Photosynthesis Summary Equation
LIGHT ENERGY
6H2O + 6CO2
water
carbon
dioxide
6O2 + C6H12O6
oxygen
glucose
Photosynthesis:
•
Two main Stages
•1. Light-Dependent Reactions
Capture sunlight energy
Use energy to make ATP and
NADPH.
•2 Light Independent Reactions
– Build Carbohydrates
• IN PLANTS-THE WHOLE PRODUCTION
TAKES PLACE IN THE CHLOROPLASTS
The chloroplasts and pigments
Photosynthesis:Light
• Light is a form of energy from the sun
• Electromagnetic Spectrum-all the
wavelengths of light
• Visible Light Spectrum-a portion-we
can see— Photosynthesis
• All butGreen&YellowUsed
• Shorter=more energy
The
V.L.S.
Wavelength: Shorter
Energy:
More
Longer
Less
•Pigments-absorb light in V.L.S.
.
Chlorophyll-main pigment
Carotenoids—help out
Pigments
Absorb certain
wavelengths
• Color you see are
the wavelengths
NOT absorbed
• A few absorb so
many, they
appear dark or
black
chlorophyll a
chlorophyll b
Wavelength (nanometers)
PHOTOSNYTHESIS PROCESS
OVERALL
• Light Reactions: Chlorophyll molecules in Thylakoid
absorb light energy, energizing electrons; electrons
are lost and used to drive the synthesis of ATP.
– Water donates electrons and hydrogens.
• NADPH forms.
• Dark Reactions: The ATP and NADPH along with
CO2 are used (in the dark) to make sugar in the
stroma in the Calvin Cycle.
The Sugar initially produced is
used by the plant to make
other organic compounds.
• Plants will use the sugars made to
FUEL their metabolic activities too!!