photosynthesis ai

Question 1

What is the primary function of the Calvin Cycle?

Answer 1

To convert carbon dioxide into glucose through a series of reactions in the stroma of the chloroplast

The Calvin Cycle is also referred to as the light-independent reactions of photosynthesis.

Question 2

What are the three major phases of the Calvin Cycle?

Answer 2

• Carbon Fixation
• Reduction
• Regeneration of RuBP

RuBP stands for Ribulose-1,5-bisphosphate.

Question 3

What enzyme catalyzes the first reaction in the Calvin Cycle?

Answer 3

RuBisCo

RuBisCo stands for Ribulose-1,5-bisphosphate carboxylase/oxygenase.

Question 4

What is produced during the Carbon Fixation phase of the Calvin Cycle?

Answer 4

Two three-carbon molecules (3-PG) from CO2 and RuBP

3-PG stands for 3-phosphoglycerate.

Question 5

What does G3P stand for and what is its significance in the Calvin Cycle?

Answer 5

Glyceraldehyde-3-phosphate; it can be used to produce glucose

Two G3P molecules are needed to synthesize one glucose molecule.

Question 6

Fill in the blank: The products of noncyclic photophosphorylation are _______ and _______.

Answer 6

ATP and NADPH

Question 7

What distinguishes cyclic from noncyclic photophosphorylation?

Answer 7

• Cyclic: Only PSI, no water used, no O2 made, no NADPH made
• Noncyclic: PSI and PSII, water used, O2 made, NADPH made

PSI stands for Photosystem I and PSII stands for Photosystem II.

Question 8

What is the net reaction of the Calvin Cycle?

Answer 8

3CO2 + 6NADPH + 5H2O + 9ATP → G3P + 2H+ + 6NADP+ + 9ADP + 8Pi

This reaction summarizes the inputs and outputs of the Calvin Cycle.

Question 9

What role do mycorrhizae play in photosynthesis?

Answer 9

They form symbiotic relationships with plants, aiding in carbon sequestration and providing carbon for light-independent reactions

Mycorrhizae are fungi that associate with plant roots.

Question 10

True or False: The reduction phase of the Calvin Cycle requires ATP and NADPH.

Answer 10

True

Question 11

What is the main purpose of the regeneration phase of the Calvin Cycle?

Answer 11

To regenerate RuBP for the cycle to continue

ATP is used in this phase to regenerate RuBP.

Question 12

Why do plants with green leaves thrive in blue-purple wavelengths of light?

Answer 12

Chlorophyll absorbs blue-purple light and reflects green light

This maximizes their ability to undergo light-dependent reactions.

Question 13

What is the difference between C3, C4, and CAM plants regarding photorespiration?

Answer 13

C3 plants primarily use RuBisCo, C4 plants have a mechanism to minimize photorespiration, and CAM plants open stomata at night

Each type of plant has adapted unique strategies to mitigate photorespiration.

Question 14

What do the light-independent reactions of photosynthesis produce?

Answer 14

Glucose and other carbohydrates

These products are synthesized from G3P.

Question 15

What are mycorrhizae?

Answer 15

A class of fungi associated with the roots of most plants that help sequester carbon from the atmosphere.

Mycorrhizae provide CO2 to their plant hosts, aiding in photosynthesis.

Question 16

What is the role of mycorrhizae in photosynthesis?

Answer 16

They assist plants in the light-independent reactions of photosynthesis by providing CO2.

Plants with mycorrhizal colonies thrive compared to those without.

Question 17

What is photorespiration?

Answer 17

A wasteful process where RuBisCo binds O2 instead of CO2 when O2 concentration is high.

It uses energy but does not produce useful intermediates for the Calvin Cycle.

Question 18

What enzyme catalyzes the first reaction in the Calvin Cycle?

Answer 18

RuBisCo.

RuBisCo can bind both CO2 and O2.

Question 19

Under what conditions do stomata typically open in C3 plants?

Answer 19

High humidity, heat, low atmospheric CO2 concentrations.

Stomata are small pores on the underside of leaves for gas exchange.

Question 20

What is a unique characteristic of C3 plants regarding photorespiration?

Answer 20

C3 plants have no mechanisms to mitigate photorespiration.

The Calvin Cycle occurs in mesophyll cells, making them vulnerable to this process.

Question 21

How do C4 plants mitigate photorespiration?

Answer 21

C4 plants use a spatial mechanism to concentrate CO2 in bundle sheath cells.

PEP carboxylase catalyzes the initial reaction in the Calvin Cycle.

Question 22

What is the function of PEP carboxylase in C4 plants?

Answer 22

It catalyzes the production of oxaloacetate from phosphoenolpyruvate and CO2.

This reaction occurs in mesophyll cells.

Question 23

What is the significance of bundle sheath cells in C4 plants?

Answer 23

They house the Calvin Cycle and are spatially separated from stomata, reducing CO2 loss.

Malate produced in mesophyll cells is transported here.

Question 24

How do CAM plants reduce CO2 loss?

Answer 24

They keep stomata closed during the day and open at night to accumulate CO2.

CO2 is fixed in the Calvin Cycle during the day.

Question 25

What environmental conditions do CAM plants typically adapt to?

Answer 25

High temperatures and dry conditions. ## Footnote They are often found in desert or tropical environments.

Question 26

What happens during the night for CAM plants?

Answer 26

Stomata open to allow CO2 intake and PEP carboxylase catalyzes CO2 fixation. ## Footnote This process helps accumulate CO2 for daytime use.

Question 27

What types of plants may not contain stomata?

Answer 27

Certain aquatic plants or those adapted to specific environments. ## Footnote They may use other structures for gas exchange.

Question 28

How do fungi produce their own food and energy?

Answer 28

They are autotrophs but not photosynthetic; they obtain nutrients through decomposition. ## Footnote They absorb organic compounds from their environment.

Question 29

True or False: Photorespiration is beneficial for plants.

Answer 29

False. ## Footnote It is considered a wasteful process that expends energy without producing useful products.

Question 30

What is the primary purpose of photosynthesis?

Answer 30

To synthesize glucose using light energy, CO2, and H2O ## Footnote Photosynthesis is essential for plants and some prokaryotic organisms to produce their own food.

Question 31

Where do the light-dependent reactions of photosynthesis occur?

Answer 31

In the thylakoid membrane of the chloroplast ## Footnote These reactions use light energy to produce ATP and NADPH.

Question 32

What are the two phases of photosynthesis?

Answer 32

Light-dependent reactions and Calvin Cycle (dark reactions) ## Footnote Both phases occur in the chloroplast but in different regions.

Question 33

What is the net reaction of photosynthesis?

Answer 33

6CO2 + 6H2O → C6H12O6 + 6O2 ## Footnote This reaction summarizes the conversion of carbon dioxide and water into glucose and oxygen.

Question 34

What is chlorophyll?

Answer 34

The most abundant photopigment in plants that absorbs light energy ## Footnote Chlorophyll is vital for capturing sunlight during photosynthesis.

Question 35

What wavelengths of light does chlorophyll absorb?

Answer 35

400 - 500 nm (purple/blue) and 600 - 700 nm (yellow/orange/red) ## Footnote Chlorophyll reflects green light, which is why plants appear green.

Question 36

What are the products of the light-dependent reactions?

Answer 36

ATP and NADPH ## Footnote These products are used in the Calvin Cycle for glucose synthesis.

Question 37

What do the light-dependent reactions utilize to produce energy?

Answer 37

Light energy and water ## Footnote The reactions also release oxygen as a byproduct.

Question 38

How do photosynthesis and cellular respiration compare in terms of redox reactions?

Answer 38

Both involve redox reactions, but photosynthesis reduces CO2 to form glucose while cellular respiration oxidizes glucose to generate ATP ## Footnote This illustrates the cyclical nature of these processes in plant cells.

Question 39

What is the role of NADPH in photosynthesis?

Answer 39

It acts as an electron carrier in the Calvin Cycle ## Footnote NADPH is produced during the light-dependent reactions.

Question 40

Which organisms besides plants are capable of photosynthesis?

Answer 40

Cyanobacteria and various types of algae ## Footnote These organisms are also considered autotrophs.

Question 41

What is the function of stomata in plants?

Answer 41

To facilitate gas exchange (O2 and CO2) ## Footnote Stomata also play a role in transpiration.

Question 42

Fill in the blank: Photosynthesis is considered a _______ process.

Answer 42

anabolic ## Footnote It builds glucose from simpler molecules.

Question 43

Fill in the blank: Cellular respiration is largely a _______ process.

Answer 43

catabolic ## Footnote It breaks down glucose to release energy.

Question 44

What are thylakoids?

Answer 44

Thin membrane-bound structures in chloroplasts where light reactions occur ## Footnote Thylakoids are stacked to form grana.

Question 45

What is the stroma in chloroplasts?

Answer 45

The thick, aqueous solution that serves as the cytoplasm of the chloroplast ## Footnote It contains enzymes for the Calvin Cycle.

Question 46

What is the innermost membrane in the chloroplast called?

Answer 46

Thylakoid membrane ## Footnote The thylakoid membrane is functionally equivalent to the cristae membrane in mitochondria.

Question 47

Which chloroplast membrane is functionally equivalent to the cristae membrane in mitochondria?

Answer 47

Thylakoid membrane

Question 48

TRUE or FALSE: Most chlorophyll pigments absorb light that falls within the ~500 - 600 nm range on the visible light spectrum.

Answer 48

FALSE ## Footnote Most chlorophyll pigments reflect light that falls within this wavelength range.

Question 49

What process occurs during the light-dependent reactions of photosynthesis?

Answer 49

Electron transport chain and ATP synthesis

Question 50

What is the first photosystem in the photosynthetic electron transport chain?

Answer 50

Photosystem II

Question 51

What is produced from the oxidation of water in Photosystem II?

Answer 51

Oxygen (O2)

Question 52

What electron carrier is reduced in Photosystem II?

Answer 52

Plastoquinone (Pq)

Question 53

What is pumped from the stroma into the thylakoid lumen during the light reactions?

Answer 53

Protons (H+)

Question 54

Which reaction center is associated with Photosystem I?

Answer 54

P700

Question 55

What happens to electrons from plastocyanin in Photosystem I?

Answer 55

They are passed to chlorophyll a and then to ferredoxin.

Question 56

What is the final electron carrier in the electron transport chain of Photosystem I?

Answer 56

Ferredoxin (Fd)

Question 57

What is the product of the reduction of NADP+ in Photosystem I?

Answer 57

NADPH

Question 58

Water is split into oxygen at which of the following protein complexes?

Answer 58

Photosystem II only

Question 59

What are the two types of photophosphorylation?

Answer 59

Cyclic and Noncyclic

Question 60

Fill in the blank: In cyclic photophosphorylation, _______ is not used.

Answer 60

H2O

Question 61

Fill in the blank: In noncyclic photophosphorylation, _______ is produced.

Answer 61

O2

Question 62

In cyclic photophosphorylation, is NADPH produced?

Answer 62

No

Question 63

In noncyclic photophosphorylation, ATP is produced for _______.

Answer 63

Calvin Cycle

Question 64

What is the role of ATP Synthase in the chloroplast?

Answer 64

Synthesize ATP from the proton gradient

Question 65

What contributes to the synthesis of ATP during the light reactions?

Answer 65

Proton gradient