Photosynthesis overview + Light reactions

How do diffrent organisms get glucose to preform cell respiration

humans - eating

plants - photosynthesis

Photosynthesis organims

Plants

Algae (protists)

Cyanbacteria

define autotrophs

Organisms that make thier own food

Photosynthesis energy transformation

Light energy is transfomred into chemical energy

Photosynthesis equation

6CO2 + 6H2O + Energy —> Glucose + 6O2

where does the CO2 come from needed in photosynthesis

the atmosphere (enters through stomata)

Where does the H20 come from needed in photosyntheis

from the ground

what type of reaction is photosynthesis

Endergonic reaction

relation between cellular respiration and photosynthesis

inverse reaction equations

significance of chlorplasts

where photsynthesis happens

where are chloroplasts found

plant cell type called mesophyll cells

What is stroma in chloroplasts

gel-like substance

what are thylakoids in chloroplasts

one disk

what are granum in chlorplasts

stack of disks

Important pichure of photosynthesis

2 process in photsynthesis

Light reactions

dark reactions

general idea of light reaction

uses light energy to capture electrons and built up a little ATP

occurs in thylakoids

general idea of dark reactions

Uses ATP and electrons from light reactions to build glucose from CO2 (also called calvin cycle)

Occurs in Stroma

What does H20 get turned into during light reaction and where do the products go?

Oxygen - exists the cell

ATP - gets used in calvin cycle

NADPH - Gets used in Calvin Cycle

3 components of light reactions

1. Photosystem II

2. ETC

3. Photosystem I

what is a photosystem

A collection of light harvesting complexes containing chlorophyll and a reaction-center complex that contains a special pair of chlorophylls and a primary electron acceptor

Photosystem II steps

1. Sunlight energizes chlorophyll molecules which funnel energy to a special pair

2. Special pair receives too much energy that electron is taken by the primary acceptor (Pheophytin)

3. Electron is replaced in the speical pair by taking an electron from a water molecule

What is the primary acceptor in Photosytem II

Pheophytin

What happens when that speical pair takes an electron from the water molecules

produces oxygen and 2 hydrogens

ETC steps

Electrons are passed from pheophytin to the electron transport chain

1. The energy released when passing electrons between proteins is used to transport H+ and build up its concentration inside the thylakoids

2. H+ passivly diffuses through ATP synthase to make ATP

3. electron contuines to move through photosystem I

why cant the cell use the ATP used in the ETC

too unstable

Photosystem I steps

Electrons from the ETC are passed to a speical pair

1. These electrons replace the ones lost due to the primary acceptor (cholorphyll A0) during light energy transfer

2. These electrons are passed to ferrodixin

3. Ferrodoxin then hands the electrons over to NADP+ to create NADPH

4. NADPH carries electrons to calvin cycle

Primary electron acceptor of PS1

Chlorophyll A0

Wavelengths used in photosynthesis

400-450nm and 650-670nm

Important Pichure of light reactions