Grade 12 Biology; Photosynthesis

;Photosynthesis Equation

6H20 + 6CO2 + Sunlight ----> C6H1206 + 602

6 Water + 6 carbon dioxide +sunlight ----> glucose + oxygen

Chlorophylls

Absorb red and light, reflect green light

Carotenoids

Absorb blue and green light, reflect yellow, orange, red

What happens when a photon of light hits a photosystem

Stage 1: sunlight strikes the antenna molecules, the antenna molecules absorb the light energy and pass it around until it reaches the reaction

Stage 2: reaction center absorbs the energy and becomes excited

Stage 3: electrons are passed from the reaction center to the primary electron acceptor

Pigments

compounds that absorb certain wavelengths of light

Light dependent reactions

Absorb photons of light

reactants: H2O, light, NADP+, ADP

Products: O2, ATP, NADPH

water is split to release electrons and oxygen, electrons move along the ETC to make NADPH and ATP. Oxygen is released to the environment

Calvin Cycle

reactants: ATP, NADPH, CO2

products: glucose

use the energy in ATP/NADH

to convert CO2 into glucose

Calvin Cycle Diagram

For 1 glucose molecule this cycle has to happen twice

uses a total of:

6 CO2

18 ATP

12 NADH

Leaf Anatomy Diagram

Palisade Mesophyll

Where photosynthesis occurs

Spongy Mesophyll

Photosynthesis also happens here, but it is also designed for gas exchange

Phloem (veins)

transports sugar, proteins and other organic molecules

delivers sugar to root or grain

Xylem

transports water and other water-soluble nutrients

delivers water from soil

stomata function

CO2 and H20 to enter

02 to exit