bio ch 7

convert sunlight energy to energy carrier molecules

convert energy in carrier molecules into glucose

captured by chlorophyll and accessory pigment molecules that allow chloroplasts to absorb light at different wavelengths

where light dependent reactions occur in the chloroplasts in special photosystems

captures CO2 and stores it in glucose molecules.

• thin
• large surface area
• waxy cuticle
• transparent epidermis

• site of photosynthesis. usually located in leaves.
• Membrane bound organells with an inner and outer membrane
• Photosynthesis takes place in thykaloid
• Grana stacks of thykaloid
• calvin cycle takes place in stroma

• chloroplasts located in mesophyll
• stroma control gas exchange

• 6 CO2 + 6
• H2O + light energy C6H12O6 + 6O2

• •Inorganic
• molecules are converted into organic molecules

• •Light
• energy is trapped in the bonds of organic molecules (glucose)

• •Oxygen
• is produced

• •Can
• be broken down into 2 stages

• –Light
• reactions and Calvin cycle

• •Energy
• from sunlight is trapped in NADPH and ATP

•H2O molecules are split

•O2 is produced

• •Energy
• from these rxns
• drives the Calvin cycle

• •Takes
• place in the stroma

• •Enzymes
• convert CO2 to 3 carbon sugar using energy from
• NADPH and ATP

•

• •Electromagnetic
• spectrum includes energy that is visible and invisible

• •Wavelength
• energy consists of photons

• •Shorter
• the wavelength, the higher the energy

• •Visible
• light excites electrons in plant pigments

• –Chl-a, Chl-b,
• Carotenoids

• •Pigments
• utilize specific wavelengths

• •Amt of
• sunlight energy that is converted into biological molecules

• •Most
• light is reflected or passes through (transmitted) the leaf

• •Within
• the thylakoid membrane are many photosystems

• •Each
• photosystem is a protein complex surrounded by chl

• •Chl e-
• are excited by light

• •Excited
• e- are captured by primary e- acceptor

• •Photosystems
• are followed by ETC

• •e-
• are continually supplied by splitting H20

• •Split
• H2O also supplies H+, which increases concentration gradient
• in thylakoid space

• •Excited
• e- enter ETC II, which generates ATP via chemiosomosis (H+ gradient and ATP synthase)

• •e-
• from PSII supply PSI

• •Chl in
• PSI produces e-

• •Excited
• e- enter ETC I

• •NADP+
• accepts 2 e- to become NADPH

• •NADPH
• supplies energy to Calvin cycle

•PSII

–H+, e-, ATP, O2

•PSI

–NADPH

–

• •See
• “Summing Up” box on p. 120

• •Energy
• in the form of ATP and NADPH supplied by the light reactions

• •G3P
• is synthesized from CO2

• •Steps
• of Calvin cycle:

1.Carbon fixation

2.Synthesis of G3P

3.Regeneration of RuBP

• •Carbon
• “fixation” describes the incorporation of inorganic carbon into organic
• molecules

• –Only
• in plants, bacteria, archaea

• •In
• photosynthesis, 3 CO2 combine with 3 RuBP with
• help of rubisco
• enzyme

• •PGA
• is formed

• •Series
• of enzyme catalyzed steps

• •Uses
• ATP and NADPH

• •Converts
• 6 PGA molecules to 6 mols of
• G3P

• •Enzyme
• catalyzed

• •Uses
• ATP

• •5
• G3P molecules are used to regenerate RuBP

• •Remaining
• 1 G3P exits the cycle

•1 molecule of G3P leaves cycle

• •Combines
• with G3P from prior Calvin cycle

• •Forms
• 1 glucose