Photosynthesis Additional Practice

Question 1

Photosynthetic Pigment

Answer 1

Colored compounds embedded in chloroplasts which absorb light of a short range of wavelengths and reflect light of other wavelengths on a visible spectrum

Question 2

Interdependence of Light Dependent and Interdependent Reactions

Answer 2

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

Question 3

Role of Hydrogen

Answer 3

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

Question 4

Respiration Chemiosmosis VS Photosynthesis Chemiosmosis

Answer 4

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

Question 5

Photosynthesis VS Respiration

Answer 5

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

Question 6

Limiting Factors of Photosynthesis

Answer 6

Temperature

CO2 Concentration

Light Intensity

Question 7

Difference with Cyclic and Non-Cyclic Photophosphorylation

Answer 7

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

Question 8

Temperature as a Limiting Factor

Answer 8

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

Question 9

Adaptations of the Chloroplast for Photosynthesis

Answer 9

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

Question 10

ETC in Respiration VS Photosynthesis

Answer 10

Respiration happens in inner mitochondrial mb
Photosynthesis happens in thylakoid mb in chloroplast

Respiration has electrons donated by RedNAD and RedFAD at the beginning of the ETC
Photosynthesis has electrons donated by chlorophyll a in PSII or water

Respiration has RedNAD and RedFAD oxidized
Photosynthesis has NADP get reduced

Respiration has Oxygen as the final electron acceptor
Photosynthesis has NADP as final electron acceptor

Question 11

CO2 Concentration as a Limiting Factor

Answer 11

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

Question 12

Chlorophyll

Answer 12

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

Question 13

Photosynthesis

Answer 13

A process where light energy is converted into chemical energy which can be used to synthesize large organic molecules from smaller inorganic substrates

Question 14

Light Intensity as a Limiting Factor

Answer 14

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

Question 15

Advantages of Structured Array of Different Pigment Molecules in a System

Answer 15

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

Question 16

LDR VS LIR

Answer 16

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