Just wonderin'?

Question

1. Electrons leaving ____ are replaced by electrons provided when ____.

a) photosystem I, oxygen is split

b) photosystem II, oxygen is split

c) photosystem II, glucose is broken down

d) photosystem II, water is split

2. Plants use ____ in the production of glucose.

a) ATP

b) NADPH

c) Carbon Dioxide

d) all of the above

3. Protons want to move ____.

a) from low concentration to high concentration

b) from the stroma into the thylakoid compartment

c) from the thylakoid compartment to the stroma

d) from Photosystem I to Photosystem II

Answer 1

1. Electrion leaving Photosystem I are replaced by electrion provided when water is split.

- In photosysthesis O2 is produced by the splitting of water. This process is call photolysis, essencially an Oxidation of H2O (which releases an electron). This process is in fact one the most powerful oxidation reaction in biology.

- remember in photosynthesis (photo- light, synthesis- production) we are synthesizing glucose from CO2, H2O and light energy.

2. Plants use ATP, NADPH and CO2 in the production of glucose.

-ATP is the universal energy molecule of biological systems, it is needed to run many reactions.

-NADPH is an energy carrier, as a reducing agent (NADP+ is an oxidizing agent)

- 6 CO2 + 12 H2O + light = glucose + 6O2, carbon dioxide is the carbon source fo glucose.

3. Protons want to move from the thalakoid compartment (or lumen) to the stroma.

- Firstly, molecules always move from high concentration to low concentration. This is the rule of the universe, from order to disorder, from high to low, from close to far apart....

- Secondly, in photosyntheisis the light-dependent reactions, which takes place in the thylakoid memebrane pump H+ ions into the tylakoid lumen from the stroma, increasing its concentration in these compartments. Since things move from high to low, H+ ions will want to move back into the stroma (This drives the production of ATP....akin to electron chain transport in cellular respiration)