Photosynthesis Lab Review

Photosynthesis• Plants, algae, and some bacteria convert light

energy into chemical energy that is stored in sugars

• Chlorophyll is the primary pigment in chloroplasts

Plant Pigment Chromatography

• Paper chromotography is used to separate a mixture into its component molecules

• The different molecules move up the paper at different rates because of differences in:– Solubility, molecular

mass, and hydrogen bonding with the paper

• You separated plant pigments using an organic solvent (acetone)

Analysis of Results

• Movement of pigment relative to movement of solvent is a constant, Rf (Reference front)

• Rf = distance pigment moved/distance solvent moved

Photosynthesis—Light Reactions• Light energy excites electrons in plant pigments• Boosts them to

a higher energy state

• High energy electrons reduce electron acceptors in the thylakoid membrane

• Energy is captured in NADPH & ATP

DPIP as an Electron Acceptor

• You measured rate of electron excitation when light hits chlorophyll

• DPIP is an electron acceptor• As DPIP is reduced, it changes from blue to

colorless• To measure the color change, you used a

spectrophotometer– Measures amount of light absorbed or transmitted

by the sample

Design of the Experiment

Results• As

chlorophyll’s electrons are exited, they reduce the DPIP, and the sample becomes more and more pale, and the transmittance increases

Cellular Respiration Lab• Occurs in every cell of all living things• Mitochondria• Nutrients (sugars) convert ADP to ATP• ATP used for all cellular activities that require

energy• C6H12O6 + 6O2 -------->

6CO2 + 6H2O + ~38 ATP

Design of the Experiment

• You measured amount of oxygen consumed by peas using a respirometer

Design of the Experiment

Results– temp = respiration– germination = respiration