Biology- Chapter 7: Photosynthesis

Photosynthesis

Conversion of light energy from the sun into chemical energy.

chlorophyll

the green color pigment in plants that trap sunlight for photosynthesis.

Stomata

Small openings on the underside of a leaf through which oxygen and carbon dioxide can move

Stroma

the fluid portion of the chloroplast; outside of the thylakoids

Thylakoid

A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy.

Grana

stacks of thylakoids

The simplified Equation for Photosynthesis

6CO2 + 6H2O + light energy --> C6H12O6 + 6O2

Light reactions

The first of two major stages in photosynthesis (preceding the Calvin cycle). These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process.

Calvin Cycle

uses ATP and NADPH from the light-dependent reactions to produce high-energy sugars from carbon dioxide

carbon fixation

The initial incorporation of carbon into organic compounds.

Wavelength

The distance between two corresponding parts of a wave

electromagnetic spectrum

All of the frequencies or wavelengths of electromagnetic radiation

Why are leaves green?

The chlorophyll reflects green light and absorbs other colors.

Carotenoids

They absorb and dissipate excessive light energy that would otherwise damage the chlorophyll

Photon

A particle of electromagnetic radiation with no mass that carries a quantum of energy

Photosystem

cluster of chlorophyll and proteins found in thylakoids

reaction center chlorophyll

transfers electrons to an electron acceptor

primary electron acceptor

When a chlorophyll electron rises to a higher level, ultimately, an electron has to go somewhere here.

What does the Calvin Cycle produce?

G3P (contains three fixed carbon atoms)

C3 plants

plants that use CO2 directly from the air to drive the Calvin Cycle

When do CAM plants open their stomata? Why?

at night, to minimize water loss

When do C4 plants close their stomata?

When the weather is hot and dry, thus conserving water.

Two pathways of evolutionary adaptations that maintain photosynthesis

C4 and CAM plants

Chloroplast

light-absorbing organelles