BIOL-213 Final Exam Review Chapter 10

Photosynthesis chemical reaction

6CO2+6H20—>C6H12O6+6O2

Autotrophs

Self feeders: plants, algae and cyanobacteria

Heterotrophs

Other feeders: must consume other organisms

In photosynthesis….

It’s a redox process

2 Processes of Photosynthesis

Light reaction—(H2O and O2) and carbonfixation reactions—(CO2, Calvin Cycle, sugars and)

Ways a photon interacts with a molecule

Bounces off

Passes through

Be absorbed

Molecules can be in an excited state

Pigment define?

Molecules that absorbs specific wavelengths in visible range of light

Primary pigment is

Chlorophyll

What is the absorption spectrum and action spectrum

Absorption spectrum-Plot of wavelengths absorbed by pigment (450)

Action- Plot of photosynthetic rate against wavelength

Two light harvesting complexes in photosynthesis

2 Photosystems

photosystem 1-has P700 chrolophyll-absorbs best at 700nm

photosystem 2-has P680 chlorophyll-absorbs best at 680nm

Role of Noncylic and cylic electron transport

Noncylic- Movement of electrons from photosystem 2 to 1

Cylic-only occurs in photsystem 1

Role of accessory pigments

Helps plant cells; increases range of light energy

Role of rxn center

Transfers electrons out of photosystem (from light)

Role of primary electron carrier

Takes electrons out of photosystem into calvin cycle

Define Photophosphorylation

Generating gradient of hydrogen, proton ions through an electron transport chain; (This differs from oxidative phosphorylation by not moving to oxygen)

Define carbon fixation

Carbon fixation- Calvin cycle

Role of rubisco ATP and NADPH

CO2 binds to 5-L RuBP, catalyzed by ribose biphosphate

ATP- Used in a couple steps; reduction of sugars

NADPA- Electrons carried over

Calvin cycle stimulated by light

Induces/induction- pH changes in stroma that favors rubisco attraction

Light- induced electron transport; reduces disulfide bonds: promotes Calvin Cycle

Define Photorespiration

Rubisco is carboxylase also act as an oxygenase, adds O2 to RuBP instead of CO2.

Advantage and disadvantage to photorespiration

Advantage-allows for oxygen to be reduced

Disadvantage- Energy expensive requires energy and ATP

C3 Plants

First product of CO2 fixation is 3PG (3Carbons). On hot days, photorespiration occurs.

C4 Plants

First product of CO2 fixation is oxaloacetate (4 Carbons). No photorespiration on hot days