Unit 3 Slides Flashcards
Photosynthesis occurs in
Plants, algae, certain other protists, and some prokaryotes
Primary Productivity
Ability of the environment to generate bio mass
Endosymbiont theory
the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms
Photosynthesis equation (other way around is cellular respiration)
6 CO2 + 12 H2O + Light Energy = C6H12O6 + 6 O2 + 6 H2O
Chloroplasts split…
H2O into hydrogen and oxygen
Incorporating the electrons of hydrogen -> sugar molecules and releasing oxygen as a by-product
Photosynthesis reverses the direction of…
Electron flow compared to respiration
Photosynthesis is what type of reaction
Redox reaction
H2O is oxidized and CO2 is reduced
Photosynthesis is what type of process
Endergonic process
The energy boost is provided by the light
Photosynthesis consists of
The light reactions and Calvin Cycle
The light reactions (in the thylakoids)
Somit H2O
Release O2
Reduce NADP+ to NADPH
Generate ATP from ADP by phosphorylation
The Calvin cycle forms… (in the stroma)
Sugar from CO2
Using ATP and NADPH
Calvin cycle begins with
Carbon fixation
Incorporating CO2 into organic molecules
Chloroplasts thylakoids transform ___ into ___ of ___ and ____
Light energy into chemical energy
ATP and NADPH
Light is a form of what type of energy
Electromagnetic energy
Also called as electromagnetic radiation
Like other electromagnetic energy, light travels in
Rhythmic waves
Wavelength determines the type of…
Electromagnetic energy
Electromagnetic spectrum
Is the entire range of electromagnetic energy, or radiation
Visible Light
Consists of wavelengths that produce colors we can see
Pigments are substances that
Absorb visible light
Different pigments absorb different wavelengths
Wavelengths that are not absorbed are
Reflected or transmitted
Leaves appear green because chlorophyll…
Reflects bad transmits green light
The absorption spectrum of chlorophyll suggests that
Violet-blue and red light work best for photosynthesis
Chlorophyll a is the ___ ___ pigment
Main photosynthetic
When a pigment absorbs light, it goes from a
Ground state to an excited state
Which is unstable
When excited electrons fall back to the ground state
Photons are given off
An afterglow called fluorescence
If chlorophyll is illuminated
The isolated solution of chlorophyll will fluoresce
Giving off light and heat
Green reflects…
Red
The light-harvesting complexes transfer…
The energy of photons to the reaction center
Photosystem I is the best at
absorbing a wavelength of 700 nm
So;par powered transfer of an electron from chlorophyll a molecule to the primary electron accept ion
Is the first step of light reactions
The reaction center chlorophyll a of PS II is called
P680
The reaction center chlorophyll a of PS I is called
P700
Linear electron flow
The primary pathway, involves both photosystems and produces ATP and NAHPH using light energy
During light reactions, there are two possible routes for electron flow:
Cyclic and linear
A photon hits a pigment and its energy is pass amount pigment molecules until it excites
P680
An excited electrons for P680 is transferred to
the primary electron acceptor
We now call it P680+
P680+ is a very strong
Oxidizing agents
H20 is split by enzymes, and the electrons are transferred from the
hydrogen atoms to P680+, thus reducing it to P680
O2 is released as a
by-product of this reaction
Each electron “falls” down an electron transport chain from the
Primary electron acceptor of PS II to PS I
Energy released by the
Fall drives the creation of a proton gradient across the thylakoid membrane