photosynthesis

Question 1

what is an antenna complex?

Answer 1

reaction center shooting up a high energy electron (contains chlorophyll which absorbs to energize electron)

Question 2

what is photorespiration? how can it be avoided?

Answer 2

rubisco binds with o2, co2 can’t enter the calvin cycle and rubisco needs to be removed as waste…less G3P produced, take energy to remove

• keep co2 high around rubisco
• keep o2 away (or low) around rubisco

Question 3

where does the electron come from in the light dependant reaction?

Answer 3

protein Z breaks h2o: proton, electron and o2 produced as waste
electron then gets energized by sunlight

Question 4

what are the complexs that make up the light dependant reaction?

Answer 4

Photosystem II (PSII)
b6f
Photosystem I (PSI)
NADP+ reductase

Question 4

what are the parts of a chloroplast?

Answer 4

stroma: liquid
thylakoid: sack like thing inside chloroplast (light dependant reaction occurs along its membrane)
- granum: stack of thylakoids
- grana: multiple stacks of thylakoids
lumen: inside a thylakoid
Thylakoid membrane
Inner/outer membrane

Question 4

Cyclic vs non cyclic electron flow

Answer 4

cyclic: electron is PSI passes back thru b6f for an extra proton
no NADPH is produced, cell can’t survive on just cydic(BUT more ATP is produced)

non cyclic: electron passes directly from PSI

Question 4

What are the light dependant vs independent reactions

Answer 4

independant: calvin benson cycle
dependant: light reaction (photophosporylation)

Question 4

what molecule/enzyme does primary carbon fixation?

Answer 4

in C3 plants: rubisco
in C4 and CAM plants: PEP carboxylase

Question 4

how do CAM plants avoid photorespiration?

Answer 4

plants in the desert (or where its rly hot) can’t open stomates during the day cause they will lose too much water.

CAM plants avoid this and photorespiration by
- separating light dependant and independent reactions by time:
stomates open and primary carbon fixation happens at night with PEP which becomes malate and is stored in the vacuole. during the day LR and CBC.

Question 5

what is the light saturation point?

Answer 5

photosynthesis can only go so fast, the light saturation point is where the light intensity does not increase the photosynthesis rate

Question 6

what did the following people do:
- ruben and kamen
- engelmann
- joseph priestley
- jan ingenhousz

Answer 6

ruben and kamen: o2 comes from water (not co2)
- engelmann: only light that is NOT green can be used for energy
- joseph priestley: cell resp and photosynthesis are complementary
- jan ingenhousz: observed bubbles in jars with plants that were in the sun vs shade…photosynthesis produced o2 as waster

Question 7

explain the light reaction

Question 8

explain the calvin benson cycle
[use diagram]

Question 9

GRAPHS