Photosynthesis Flashcards

Question

what are the peak absorbances for chlorophyll a?

Answer 1

425nm (blue) 625nm (red)

Answer 2

445nm (blue) 645nm (red)

Answer 3

445nm (blue) 475nm (green)

Answer 4

a graph which shows the rate of photosynthesis of a pigment when it is exposed to different wavelengths of light it shows how effective different wavelengths are at promoting photosynthesis

Answer 5

to produce ATP and reduce NADP

Answer 6

cyclic phosphorylation non-cyclic phosphorylation

Answer 7

1. light strikes chloroplasts and H2O molecules split 2. electrons from PSI and PSII become excited, move out of orbitals and leave both photosystems positively charged 3. electrons from PSII are taken up by electron acceptor A 4. electrons from the splitting of H2O move along electron carriers to PSII 5. electrons from electron acceptor X move along a series of electron carriers to the+vely charged PSI 6. electrons leave PSI and re taken to electron carrier Y then to the electron acceptor NADP 7. NADP becomes negatively charged and reduced to NADPH

Answer 8

1. light striked PSI and electrons become excited, leave the photosystem and are accepted by electron acceptor X 2. the electrons cycle back to PSII via a series of electron carriers 3. energy released from the transfer is used to synthesize ATP

Answer 9

Without water, electrons, ATP and reduced NADP production stops, therefore halting the light independent reaction. This is because Photosystem II is responsible for splitting water molecules to obtain electrons and protons. Without water, the process cannot occur, halting the entire electron transport chain and subsequently affecting ATP and NADPH production

Answer 10

without light, the light- dependent stage stops. Light dependent reactions occur without light because there is no light energy to convert into chemical energy. These reactions produce energy in the form of ATP and NADPH, which are needed for light independent reactions. No light means no electron flow, and therefore no ATP or NADPH

Answer 11

Without NADP to accept these electrons, the electron transport chain grinds to a halt. This backup causes a cascade of negative effects. Firstly, the flow of electrons is disrupted, preventing the generation of a proton gradient across the thy lacoid membrane. This gradient is crucial for ATP synthesis via chemiosmosis. Consequently, the absence of NADP leads to a significant reduction or complete cessation Of ATP and NADPH production

Answer 12

Water serves as the primary electron donor in light dependent reactions. Through a process known as photolysis, water is split into protons and electrons. The released protons accumulate inside the thy lakoid lumen, creating a cone. gradient. The proton gradient drives ATP synthesis through chemiosmosis as protons flow through ATP synthase. Critically, the electrons extracted from water are essential for replacing those lost by chlorophyll in Photosystem Is thereby sustaining the electron transport chains

Answer 13

When light strikes a photosystem, it excites electrons in the pigment molecules, particularly chlorophyll. The energy from these excited electrons is used to power the electron transport chain, which generates ATP. Light energy also provides the energy needed to split water molecules

Answer 14

As electrons move through the electron transport chain, they lose energy. To prevent a buildup of electrons and to capture this energy, NADPT accepts these electrons. When NADP+ accepts these electrons, it becomes reduced to NADPH

Answer 15

Chlorophyll a is the primary pigment in photosynthesis It is the main molecule responsible for absorbing light energy and converting it into chemical energy. It is found in all photosynthetic organisms. Accessory pigments are pigments that work in conjunction with chlorophyll a. They absorb light wavelengths that chlorophyll a cannot efficiently absorb, broadening the spectrum of light for photosynthesis. Absorbed energy → chlorophyll a

Answer 16

chlorophyll b carotenids

Answer 17

a type of chlorophyll but has a different structure than chlorophyll a allowing it to absorb different wavelength of lights

Answer 18

pigments which absorb blue and green light, which chlorophyll does not absorb efficiently protect chlorophyll from damage by excessive light

Answer 19

Photosystems are protein-pigment complexes located in the thy lakoid membranes. They consist of two main components: a light harvesting complex and a reaction centre. The light harvesting complex consists of multiple pigment molecules, primarily chlorophyll and carotenoids which capture light energy and transfers it to the reaction centre. Here the energy is used to excite electrons, which are then donated to the electron transport Chain. Photosystem I and Photosystem I are the 2 primary photosystems involved in photosynthesis, working in tandem to generate ATP and NADPH

Answer 20

Electron acceptors play a vital role in the electron transport chain. These molecules accept electrons from the excited molecules in the reaction centers. As they accept electrons, they undergo reduction and pass them on to the next acceptor in the chain. This sequential transfer of electrons creates an electron flow that drives the pumping of protons across the thy lakoid membrane, leading to ATP synthesis.

Answer 21

Blue light is primarily absorbed by chlorophyll and carotenoids, ashich are key pigments in photosynthesis. It can stimulate a higher rate of electron transport, leading to increased ATP and NADPH production

Answer 22

While redlight is essential for photosynthesis, it is less efficiently absorbed than blue light. This might result in decreased NADPH and ATP production compared to full sunlight. Redlight is more effective for photosystem I which might lead to an imbalance in ATP and NADPH

Answer 23

Green light is reflected by Chlorophyll, making it inefficient for photosynthesis. Very little energy will be converted into chemical energy, leading to significantly reduced photosynthetic activity

Answer 24

This combination is considered ideal for photosynthesis as it covers a broad spectrum of light absorbed by chlorophyll. Both Photosystem I and I will be efficiently activated, leading to balanced ATP and NADPH production. This light combination often results in higher rates of photosynthesis and plant growth

Answer 25

Chlorophyll is the primary pigment for photosynthesis, absorbs light most efficiently in the red and blue wavelengths. The absorbed light energy is converted into chemical energy (ATP and NADPH) Which fuels the process. A combination of red and blue light ensures maximum absorption across a broader spectrum, maximizing the efficiency of photosynthesis.

Answer 26

The purpose of the light dependent stage is to convert light energy into chemical energy. More specifically, it produces AT P lenergy currency) and NADPH (reducing agent), which are essential for the next stage of photosynthesis, the Calvin cycle, where glucose is synthesized.

Answer 27

a gradient of protons established between the thylakoid lumen and the stroma of the chloroplasts

Answer 28

the high proton concentration in the thylakoid lumen and lower proton concentration in the stroma hence the protons in the thylakoid lumen have a high potential energy

Answer 29

the process in which protons move down an electrochemical gradient via channel proteins associated with ATP synthase

Answer 30

1. proton pumps in the thylakoid membrane actvely move protons in the lumen from the stroma/ photolysis of water also provides protons 2. some energy is released during electron transport along carriers and is used to pump protons from the stroma into the thylakoid space 3. energy is released as protons move through channel proteins (ATP synthase enzyme is associated with each channel protein) 4. energy released as protons move through the channel and is used to synthesize ATP from ADP and inorganic phosphate via ATP synthase

Answer 31

Photosystem I alone involved No H20 needed Initial donor of electrons = PSI Final donor of electrons= PSI No O2 evolved Synthesize extra ATP to satisfy the energy demands of the cell produces ATP only Electron acceptor Y alone involved

Answer 32

Both Photosystem I and II involved H20 needed to donate e to PSTI Initial donor of electrons = Ha0 O2 evolved Allows for synthesis of organic compounds in the light- independent stage Produces ATP, NADPH and O2 Electron acceptors x and Y involved

Answer 33

stroma of the chloroplast

Answer 34

CO2, gas diffuses into the chloroplasts along a cone. gradient. involves CO, binding with RUBP (Ribulose Biphosphate) which is a CO2 acceptor molecule found within the stroma Of the chloroplast Water combines with RUBP and CO2, in a reaction catalyzed by RUBISCO (Ribulose Biphosphate Carboxylase enzyme). This is a carbox - glation reaction and inorganic carbon is converted to an unstable six carbon compound (organic) As fast as CO2 is accepted by RUBP, the conc. Of CO2, in the stroma decreases. This maintains a diffusion gradient between the outside of the photosynthetic cell and the stroma - The unstable 6C compound is very quickly converted to two molecules of the 3c compound glycerate -3-phosphate (3- phosphoglycerate/ 3GPA); it is the first product of photosynthesis.

Answer 35

- The energy of some of the ATP and the reducing power of All the NADPH from the light dependent stage and are used to convert GP to TP - During the reduction phase, O2 is removed from GP using energy from the splitting of some ATP molecules -O2 combines with hydrogen from NAAPH molecules NADP is therefore regenerated and can be reused in the light dependent reactions some ADP and Pi are also regenerated for use in the light dependent stage

Answer 36

the first carboxylate of photosynthesis triose phosphate/ glyceraldehyde-3-phosphate

Answer 37

RUBP has to be regenerated for reuse in the calvin cycle During the process of regeneration, 5 out of TP molecules are used along with the rest of the ATP from the light dependent stage The TP is converted to RUP (Ribulose Phosphate) The rest of ATP is used to convert RUP → PAUBP by phosphorylation

Answer 38

- 1 TP Molecule out of the 6 TP molecules is used to form other carbohydrates ex. glucose, sucrose, starch, cellulose

Answer 39

Affects the photolysis of water and the supply of electrons to PSII as well as the supply of protons for the reduction Of NADP Affects the excitation of electrons in PSI and PSI, and the manufacture of ATP Both ATP and reduced NADP are required for the reaction of the light independent stage which includes the manufacture of carbohydrates If light intensities are low, the rate of photosynthesis is low If light intensities increase, the rate is much higher

Answer 40

Affects the light independent stage and the quantity of CO2 fixed determines the quantity of TP manufactured and the amount of Other carbohydrates synthesized Low COs conc. means less carbohydrates manufactured and vice versa

Answer 41

If water is in low supply, less water will be split to supply electrons to photosystem II for the manufacture of ATP. There will be fewer motions to reduce NADP So the rate of photosynthesis will decrease because less ATP and reduced NADP Will be manufactured When a dequate amounts of water are present, large amounts Of ATP and reduced NADP will ensure the rate of photosynthesis is higher

Answer 42

- Highest amount of photosynthesis is in the blue and red wavelengths before more electrons become excited in the photosynthetic pigments and more ATP will be produced - Least amount of photosynthesis will occur when plants are exposed to the green wavelength of light

Answer 43

- Both CO, and O2 compete for the active site of RUBISCO - RUBISCO can catalyze a reaction between RUBP+ CO2, and between RUBP+ O2 under different conditions - In the presence Of light, if CO2 levels are high, O, levels low and temp. is low., CO2 fixation is favoured - When light intensities are high.CO, levels are low, O, levels high, and temp. is high, photorespiration is favoured in which 1GP molecule is produced, along with a molecule of 2-phospho glycolate - Phosphorglycolate enters mitochondria and is used to produce CO2 Photorespiration makes photosynthesis 30-401. efficient2

Answer 44

Affects the rate of photosynthesis since enzyme - controlled reactions in the light independent stage are affected by temperature At low temperatures, there is less kinetic energy available, also less energy available for activation energy, and the rates are lower When temperatures increase, rates increase due to increased kinetic energy If temperatures go too high, enzymes become denatured and reactions slow considerably

Answer 45

Affects the enzymes involved by altering the shape of the enzyme and its active site

Answer 46

When a process is affected by more than one factors, its rate is determined by the factor which is closest to its minimum to value.

Answer 47

structure in which plants are grown under controlled environments

Answer 48

glass or plastic roof and walls plants are exposed to natural light inside the greenhouse air heats up due to incoming solar radiation artificial lighting can be used in temperate countries

Answer 49

7-10 degrees

Answer 50

10-13 degrees

Answer 51

16-21 degrees

Answer 52

soll is dry (use irrigation, hydroponics) 2.high temperatures in greenhouse l use thermostat, ventilation system) 3. extremes of light (use shade netting) 4. too much fertilizer I supply more water) S. diseases damage plant tissues I chemicals to remove pathogens)

Answer 53

burning C based fuels - increases temperature and emits So2 and NO2

Answer 54

If CO. concentrations are increased, this can improve the yield of fruits, promote flowering, improve strength of stems, increase size of flowers As CO2 conc. increases from 340→1000 ppm, net photosynthesis increases Most crops show increases in photosynthesis by about 50s. when CO2 conc. rises to 1000 ppm. ↳ The saturation point for COa conc. for most crops is reached at 1000-1300ppm CO, under ideal conditions

Answer 55

a lower level of CO2 because higher levels would kill the plant

Answer 56

increased profits from growing crops can control climatic conditions control over pests, weeds, diseases no dependence on external climate consistent supply of nutrients and water can grow exotic plants

Answer 57

operational costs are high costly to set up controls and maintain them high level of monitoring required lack of pollination can be space-consuming

Answer 58

plants are grown in an inert growing medium such as gravel, sand, coconuts etc

Answer 59

water system constantly recycles water in a closed system less use of chemicals higher yield than conventional methods plants grow in a short time initial temp, pH, CO2 conc, water supply are carefully controlled

Answer 60

diseases can be spread rapidly pH control is important to detect changes produced by microorganisms higher operative costs plants that need agents of pollination cannot grow here water loss can occur through evaporation and leaks in pipes

Answer 61

A growth chamber can range from a simple, lighted cabinet to a larger structure which provides rigorous control of several environmental factors

Answer 62

to obtain plant material to permit the selection of environmental conditions appropriate to a given plant species without regard for the season to permit environmental manpulation as an experimental variable to permit plant pathologists to fight plant diseases to make predictions about the yield nd survivability of crops

Answer 63

expensive to maintain humidity has to be carefully controlled to prevent buildup of moles problems can occur in the operation of the controls fresh air must be changed every two hours to prevent a build up of excess CO2 at night and depletion during the day

Photosynthesis Flashcards

(89 cards)