Properties of Light & Photosystems- Gen Bio 1

light

it is type of energy called electromagnetic radiation

what are the properties of EM radiation

• travels at 3 × 10⁸ m/s

• dual nature: can act as both waves or particles

• longer waves = less frequency

• short waves = higher frequency

what are the possible outcomes when light hits an object

• can be transmitted

• can be reflected

• can be absorbed (by molecules called pigments)

what are the 3 photosynthetic pigments

• chlorophyll (A & B)

• carotenoids

• phycobilins

what does chlorophyll A & B reflect

greeen

what do carotenoids reflect

orange

what do phycobilins reflect

purple or red

what are 3 components of photosystems

1. reaction center: consists of 2 chloro. A molecules

2. antennae pigments

3. primary electron acceptor

antennae pigments

accept photons & transport them to the reaction center (several hundred)

primary (I) electron acceptor

where energized electrons are handed off

cyclic photophosphorylation

when energized electrons reach the primary electron acceptor of photosystem I are sent back to the first electron acceptor chain to make more ATP

noncyclic photophosphorylation

process where light energy is used to generate ATP and NADPH, involving both photosystems I and II

where does noncyclic photophosphorylation occur

thylakoid membrane

what are 90% of the world’s plants

C3

what do C3 plants produce

G3P (glyceraldehyde-3-phosphate)

what are 10% of the world’s plants

C4

what do C4 plants produce

oxaloacetate