Lab photosynthesis

Photosynthesis

process by which green plants, algae, and some bacteria convert light energy into chemical energy stored in glucose

two stages of photosyntheis

Light reaction cycle and Calvin cycle

Light reaction cycle

light absorption in the pigments and breaking H2O molecules, releasing O2 as a byproduct. ATP and NADPH are produced. Occurs in the inner thylakoid membrane

The calvin cycle 

uses CO2 to create glucose by using the ATP and NADPH from earlier. Occurs in the stroma

photosynthesis equation 

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

photosynthesis occurs in 

chloroplasts 

chlorophyll

pigment in chloroplasts that captures light energy

pigments

capture light energy and convert it to chemical energy 

chlorophyll a

absorbs blue violet and red light, reflects green wavelengths 

chlorophyll b

accessory pigment, absorbs blue and red orange light, reflects green-yellow wavelengths 

carotenoids

accessory pigments, absorb blue and green, reflect yellow, orange, or red ex. beta carotene 

once pigments absorb light the energy is transferred to the 

reaction center, where it excites electrons 

High energy electrons are used in the light reaction to produce

ATP and NADPH

Paper chromatography

technique for the separation and identification of different plant pigments. The mixture containing the pigments to be separated is first applied as a spot or line to the paper about 1.5cm from the bottom of the paper. Then the paper is placed in a container with the tip of the paper touching the solvent. The pigments are carried along at different rates because they are not equally soluble. Less soluble pigments move slower up the paper than more soluble pigments. More polar the pigment, the further up it will move.

Carotene

Rf value of .8, band yellow to yellow orange

Xanthophylls

.18 rf, yellow band

Chlorophyll a

.6 rf, green to blue green band

chlorophyll b 

.4 rf, green to yellow green band

isopropanol 

the solvent 

most nonpolar pigment 

carotene 

if elodea plants are actively undergoing photosynthesis, the CO2 in the solution will disappear 

Phenol red 

pH indicator, yellow- acidic, more CO2, red-neutral, less CO2

when you blow in the solution it turns yellow

the CO2 from your breath dissolves in the water forming carbonic acid which lowers the pH

if a plant is photosynthesizing the solution will turn red 

the plant uses the CO2, raising the pH

sunlight includes 

visible light, UV, Infrared, X rays, radio waves, gamma rays

a white lighbulb wavelength 

400 to 700 nm, combo of visible light 

elodea plant most useful wavelengths are

red and blue

we can measure light reaction O2 release in

volumeter apparatus

stomata

microscopic structures found on the epidermis of plant leaves, stems, and other aerial organs. They serve as the primary route for gas exchange, regulating intake of H2O and O2 and release of O2. 

structure of stomata 

2 specialized guard cells flanked by neighboring epidermal cells. 

Guard cells

can change shape which regulates the opening and closing of the stomatal pore

Guard cells swell and become turgid 

gap created, allows exchange of gases

guard cells loose turgor pressure

pore closes, excess water loss prevented

banding is caused by

speed the pigment is moving