Photosynthesis Additional Practice Flashcards
Photosynthesis
A process where light energy is converted into chemical energy which can be used to synthesize large organic molecules from smaller inorganic substrates
Photosynthetic Pigment
Colored compounds embedded in chloroplasts which absorb light of a short range of wavelengths and reflect light of other wavelengths on a visible spectrum
Chlorophyll
The main photosynthetic pigment
Contains chlorophyll a and b, and absorbs red and blue light most effectively with blue light having the most absorption
Reflects green light the most
Accessory pigments help absorb a wider range of wavelengths of light to maximize photosynthesis
Limiting Factors of Photosynthesis
Temperature
CO2 Concentration
Light Intensity
Temperature as a Limiting Factor
At low temperature, rate of photosynthesis is low as enzymes are inactive
As temperature increases, rate increases due to increase in KE and increase in collisions
Optimum temperature is where photosynthesis is at its maximum because enzymes are working the best
Beyond optimum temperature the temperature becomes too high and the enzyme denatures therefore halting reaction
CO2 Concentration as a Limiting Factor
As CO2 concentration increases, rate increases
There is a point where CO2 will no longer be a limiting factor, so it won’t affect the rate of photosynthesis as it would be too saturated
Light Intensity as a Limiting Factor
As Light Intensity increases, stomata opens for CO2 to enter the leaf and increase the rate of photosynthesis
There is a point where light intensity will no longer be a limiting factor, so it won’t affect the rate of photosynthesis as it would unaffected
Photosynthesis VS Respiration
Captures energy and stores it in sugars
Release energy stored in sugars
Occurs in chloroplast
Occurs in mitochondria
CO2 and H2O are reactants
C6H12O6 and O2 are reactants
C6H12O6 and O2 are products
CO2 and H2O are products
Takes place in autotrophs
Takes place in all living things
Advantages of Structured Array of Different Pigment Molecules in a System
Enhanced light absorption since a photosystem combines different pigments it maximizes light absorption
Broad wavelength absorption, each pigment has a narrow absorption range and by combining various pigments it’ll allow photosystems to capture a broader range of wavelengths
Efficient energy transfer, as the arrangement of pigments facilitate energy transfer between them. When a pigment absorbs a photon and becomes excited, it passes onto each other until it reaches the reaction center which increases efficiency for photosynthesis
Difference with Cyclic and Non-Cyclic Photophosphorylation
Non-cyclic pathway of electrons
Cyclic pathway of electrons
PSI and PSII are used
Only PSI is used
Photolysis is required
Photolysis is not required
Source of electrons is water
Source of electrons is PSI
Products are ATP, NADPH, and Oxygen
Product is only ATP
Role of Hydrogen
Proton ions are obtained from photolysis of water
Proton ions build up in thylakoid space
ATP synthase generates ATP via chemiosmosis from the movement of hydrogen ions from the thylakoid space into the stroma
NADP accepts a proton ion from the stroma to produce RedNADP
RedNADP is oxidized to transform G3P into TP
Adaptations of the Chloroplast for Photosynthesis
Thylakoid Membranes: Provide a large surface area for the attachment of photosynthetic pigments, electron carriers and enzymes
Thylakoid Spaces: Have a small volume for the accumulation of protons and establishment of the gradient
Grana: Contains proteins network that holds the pigments allowing for maximum light absorption
Stoma Fluid: Holds all of the enzymes needed to perform light independent reaction
Lamellae: Connect Grana which maximizes photosynthesis efficiency
Interdependence of Light Dependent and Interdependent Reactions
Light independent reactions depend on dependent reaction for supply of ATP and NADPH. ATP and RedNADP are utilized in light independent reactions for the reduction of carbon dioxide into gluvose
Lack of light stops light dependent reactions and a lack of CO2 prevents PSII from functioning
LDR VS LIR
LDR takes place only in presence of light
LIR takes place in presence and absence of light
LDR takes place in thylakoid mb
LIR takes place in stroma
LDR converts light energy into chemical energy
LIR use the chemical energy to fix CO2
LDR has photolysis occur in PSII
LIR has no photolysis
Respiration Chemiosmosis VS Photosynthesis Chemiosmosis
Respiration involves ETC in cristae where ATP synthase is located
Photosynthesis involves ETC in thylakoid mb where ATP synthase is located
Respiration has energy pump protons into intermembrane space
Photosynthesis has energy pump protons into thylakoid space
Respiration’s protons come from matrix
Photosynthesis’ protons come from stoma
