BIOL 1000 Chapter 7

Photosynthesis

uses light to make food

Autotrophs

Self feeders

Photoautotrophs

Use energy grom light to make food

Heterotrophs

Consumers of biosphere

Mesophyll cells

contain 30-40 chloroplasts

Stomata

pores allowing co2 to enter and oxygen to exit

veins

deliver h2o, minerals, and sugars to all parts of plants

Chlorophyll a

absorbs blue violet and red, participates in light reactionc

chlorophyll b

absorbs blue and orange, transfers energy to a

cartenoids

pigments that reflect yellow and orange, more stable than chlorophyll, pass energy to chlorophyll, sometimes capture and dissipate light energy that would damage cell

Stages of photosynthesis

light reaction, calvin cycle

Light reactions

capturing of light energy which is absorbed by the chlorophyll, atp is produced, electrons jump and move down and energy is released

light harvesting complex

Pigment molecule bound to proteins, harvests light

Reaction center

Pair of specialized chlorophyll a molecule bound to proteins, contains primary electron acceptor

Photosystems

reaction center surrounded by light harvesting complexes, one and 2 connected by etc, photon excites electron in 2 and energy moves down primary electron acceptor, produces atp, photon in 1 excites electron, energy passed to primary electron acceptor and nadph is formed

light reactions steps

1. water split into o2 and 2h+ and 2 electrons (o released, h in thylakoid, e to primary electron acceptor

2. electron passed through etc (photosystem 2 reaction center)

3. after photosystem 1 short etc

4. chemiosmosis produces atp

Calvin cycle

1. starts with rubp, attaches to co2, result is 6 carbon molecule

2. reduction, atp and nadph are used to reduce 3 carbon molecule to g3p

3. release of g3p

4. regen of rubp, turns 3 times

C3 plants

use most common form of photosynthesisC

Photorespiration

Occurs in light and consumes o2 and releases co2C

C4 plants

modified photosynthesis which minimizes photorespiration

CAM plants

survives in dry climates, conserves water