Photosynthesis

Question 1

What is the equation for photosynthesis?

Answer 1

CO2 + H2O -> C6H12O6 + O2
(carbon dioxide and water to glucose and oxygen)
*CO2 is reduced and oxygen is oxidized

Question 2

Oxidation

Answer 2

Results in the production of electrons, protons, and O2.

*electrons and protons are incorporated into the product while O2 is a by-product.

Question 3

Reduction

Answer 3

CO2 molecules are reduced to form higher-energy carbohydrate molecules.

Question 4

Chloroplast

Answer 4

Where photosynthesis takes place.

• Captures and converts energy from sunlight.
• Stores in ATP and NADPH (energy-storage molecules).

Question 5

Thylakoid membranes

Answer 5

• Membrane bound compartments inside chloroplasts.
• Site of the light-dependent reactions of photosynthesis.
• Increase the surface area available for photosynthesis.
• more surface area = more glucose.

Question 6

Grana

Answer 6

The stack of thylakoids within the chloroplast of plant cells.

Question 7

Carotenoid light absorption

Answer 7

Carotenoids absorb green wavelengths and reflect orange, yellow, and red wavelengths.

Question 8

Carotenoid

Answer 8

Chlorophyll breaks down faster than carotenoids in the fall.
*why the leaves turn red, orange, and yellow.

Question 9

Calvin cycle (light independent reactions/ dark reaction)

Answer 9

1) Carbolyxation: CO2 is added to a 5-carbon molecule (RuBP).
2) Reduction: energy and electrons are transferred to the compounds formed in step 1.
3) Regeneration of RuBP: 5-carbon molecule is regenerated for carbolyxation.

Question 10

Photosystem II (comes first)
*light reaction

Answer 10

Supplies electrons to the electron transport chain. When it loses an electron it can pull more electrons from water.

Question 11

Photosystem I (comes second)
*light reaction

Answer 11

Energizes the electrons with more light energy so they have enough energy to reduce to NADP+.

Question 12

What causes photorespiration?

Answer 12

Occurs when rubisco adds O2 instead of CO2 to RuBP, resulting in one molecule with three carbon atoms and one molecule with only two carbon atoms.
(3-PGP and 2-phophoglycolate)

Question 13

NADP reductase

Answer 13

Reduces NADP+ to NADPH.

Question 14

Z scheme

Answer 14

Energy fluctuates (chart going up and down looks like a Z).

Question 15

Cytochrome C

Answer 15

Pumps protons across the membrane, helps with photosystem II.

Question 16

What happens when there’s not enough NADP+?

Answer 16

The electrons go back to the Pq and it goes through the chain again.

Question 17

What makes photosynthesis both an oxidation and reduction reaction?

Answer 17

Oxidation: Water is the source of electrons and oxygen is its by-product.
Reduction: CO2 molecules are reduced to form higher-energy carbohydrate molecules.

Question 18

Stroma

Answer 18

Where light independent reactions take place (Calvin cycle).

- Fluid outside of the thylakoids, within the chloroplast.