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.

Chapter 9Energy 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

•cellular respiration

ATP –Energy Currency

•

Energy Relationships

ATP

BIOSYNTHETIC PATHWAYS(ANABOLIC)

ENERGY INPUT

DEGRADATIVE PATHWAYS(CATABOLIC)

energy-poor products(such as carbon dioxide, water)

large energy-rich molecules(fats, complex carbohydrates,

proteins, nucleic acids)

simple organic compounds(simple sugars, amino acids,

fatty acids, nucleotides)

ADP + Pi

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.

• Cellular Respiration—releases energy

Photosynthesis Summary Equation

6H2O + 6CO2 6O2 + C6H12O6

water carbon dioxide

oxygen glucose

LIGHT ENERGY

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 Longer

Energy: More 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 Wavelength (nanometers)

chlorophyll b

chlorophyll a

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!!