Photosynthesis

Question 1

Photosynthesis: Light-Dependent Reaction

Answer 1

Occurs in the grana/thylakoid and utilizes light energy directly to produce ATP which powers light-independent reactions.

Note: only occurs when light is present

Question 2

Photosynthesis: Light-Independent Reaction

Answer 2

Occurs in the stroma and consists of the Calvin cycle which produces sugar in the presence of ATP which was formed during light-dependent reactions.

Note: only occurs when light is present

Question 3

Photosynthesis

Answer 3

The process by which light energy is converted into chemical bond energy and carbon is fixed into organic compounds (e.g. sugars). There are two main processes of photosynthesis:

1. Light-dependent reactions
2. Light-independent reactions

Question 4

Photosynthetic Pigments

Answer 4

Absorb light energy and use it to provide energy to carry out photosynthesis. Plants contain two major groups of pigments:

• chlorophylls (e.g. chlorophyll a, chlorophyll b)
• carotenoids (e.g. xanthophylls and phycobilins)

Question 5

Chlorophylls

Answer 5

Group of green photosynthetic pigments that absorb wavelengths of light in the red, blue, and violet range. This group includes: chlorophyll a and chlorophyll b

Note: chlorophyll b is also considered an antenna pigment

Question 6

Carotenoids

Answer 6

Group of yellow, orange, and red photosynthetic pigments that absorb wavelengths of light in the blue, green, and violet range. This group includes: xanthophylls and phycobilins.

Question 7

Antenna Pigments

Answer 7

Photosynthetic pigments that capture light in wavelengths other than chlorophyll a. Antenna pigments absorb photons of light and pass the energy along to chlorophyll a, which is directly involved in the transformation of light energy to sugar. This subgroup includes: chlorophyll b, xanthophylls, and phycobilins.

Question 8

Grana

Answer 8

The site of light-dependent reactions and consists of layers of membranes called thylakoids. It is within the thylakoid membranes that photosystems I and II take place.

Question 9

Chloroplast

Answer 9

The site of photosynthesis. Contains photosynthetic pigments and enzymes. In addition it houses the grana and stroma where both light-dependent and light-independent reactions occur, respectively.

Question 10

Photosystems

Answer 10

Light-harvesting protein complexes in the thylakoid membranes of chloroplasts found in plants, algae, and cyanobacteria. Two types exist:

• PSI (P700)
• PSII (P680)

Question 11

Photosystem II (P680)

Answer 11

• 1st protein complex in light-dependent rxns
• Enzymes capture photons of light to energize electrons that are then transferred via coenzymes and cofactors to reduce plastoquinone to plastoquinol

Question 12

Photosystem I (P700)

Answer 12

-2nd protein complex in light-dependent rxns

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