Photosynthesis Short Answer Practice

#1 What makes chlorophyll so unique?

• Made of photon-absorbing porphyrin ringwith Mg in centerNitrogen atoms around the Mg• Photon of lightresonates the e-between the singleand double bonds

#1 What makes chlorophyll so unique?

• Hydrocarbon tailAttaches to Integral protein in theThylakoid disk membrane

#2 Compare PSII and PSI

• Both absorb photons and excite e-• Both contain chlor a + other pigments

• Reaction center of PSII absorbs 680 nm• Reaction center of PS I absorbs 700 nm

• PSII receives e- from split water• PS I receives e- from Pc (end of ETC)

#2 Compare PSII and PSI

PSII PSI

-PSII gives electrons to ETC-PSI give electrons to NADP+

FOUND IN THYLAKOID DISK MEMBRANE

#3Compare chemiosmosis and ETC in mitochondrion and chloroplast:

• Mitochondrion• e- come from food

molecules• e- have high potential

energy in bonds in organic compounds

• e- passed to oxygen• Oxygen pick up H+ to

form H2O

• Chloroplast• e- come from splitting of

H2O• Light energy excites e- to a

higher energy level• e- flow from H2O to

reaction center 680 in PSII to reaction center 700 in PSI

• From PSI to NDR to reduce NADP+ to NADPH

#4 CFC’s

• Chlorofluorocarbons• Were put in aerosols, refrigerants, and styrofoam

• Products containing CFC’s were Banned by those signing the Montreal Protocol 1987

• Recovery of ozone not expected until 2060’s.

Ozone O3

• O3 (seen in teal blue in diagram)• Protective layer around the earth keeping harmful

UV rays from reaching the earth

• UV rays• (some enter, some blocked)

• Infrared (trapped)

#4 CFC’s• Cl breaks off

an oxygen from ozone (O3) so it is no longer a protective layer around the earth.

Global Warming

• refers to the rising average temperature of Earth's atmosphere and oceans

Greenhouse GasesCO2 (carbon dioxide) – most important!

H2O (water vapor)

CH4 (methane)

CFC’s (chlorofluorocarbons)

These can absorb heat and warm the atmosphere.

Causes and Effects of Global Warming• Increase in greenhouse gases: especially CO2

(mostly from fossil fuel emissions)

-Kills coral reefs-Melts polar icecaps-Raises ocean levels-Upsets weather

CFC’s and Global Warming

#4 Global Warming Solutions• Photosynthesis removes CO2

from the atmosphere • Reduce fossil fuel use (CO2 is an important

global warming gas -absorbs heat)• Use alternate energy sources (wind, solar,

geothermal, hydroelectric)