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1.

When CO2: O2 is approximately 1, RuBisCO has a lower affinity for CO2. True or false?(a) True(b) FalseThe question was posed to me in an international level competition.I need to ask this question from Higher Plants Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct answer is (b) False

The best I can explain: RuBisCO or Ribulose-1,5-bisphosphate carboxylase oxygenase catalyses the FORMATION of 3PGA from RuBP and CARBON DIOXIDE during Calvin cycle. RuBP is the PRIMARY carbon dioxide acceptor MOLECULE.

2.

_______ accepts the electrons from Pheophytin.(a) Cytochrome f(b) Cytochrome d(c) Plastoquinone(d) FerredoxinThis question was posed to me by my college director while I was bunking the class.My enquiry is from Higher Plants Photosynthesis in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The CORRECT answer is (c) Plastoquinone

Easy explanation: Plastoquinone (PQ) is an electron carrier. It accepts the ELECTRONS from PHEOPHYTIN. PQ gets 2 electrons and passes these to cytochrome b6. It ALSO plays a major role in light-dependent reactions.

3.

Plants adapted to dry tropical regions use the C4 pathway. True or false?(a) True(b) FalseThe question was asked by my college director while I was bunking the class.I'm obligated to ask this question of Higher Plants Photosynthesis in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct option is (a) True

To explain I would say: Plants using the C4 PATHWAY have special adaptations which HELP them survive extreme climatic conditions. Some such adaptations are toleration of high TEMPERATURES, response to high LIGHT intensities and lack of photorespiration.

4.

What factor determines the binding of carbon dioxide to the active site of RuBisCO?(a) Intensity of sunlight(b) Number of chloroplasts(c) Opening and closing of stomata(d) Relative O2 and CO2 concentrationThis question was addressed to me in a national level competition.My doubt stems from Higher Plants Photosynthesis topic in division Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct option is (d) Relative O2 and CO2 concentration

Easiest EXPLANATION: The active site of RuBisCO can bind to both oxygen and CARBON dioxide. It has a higher affinity for carbon dioxide. Hence, the relative CONCENTRATIONS of carbon dioxide and oxygen decide the binding of carbon dioxide.

5.

Which of these statements is false regarding the factors affecting photosynthesis?(a) The leaf orientation of a plant affects photosynthesis(b) Both internal and external factors affect photosynthesis(c) Photosynthetic rate is determined by a factor at sub-optimal level(d) Both CO2 concentration in the environment and inside the plant affect photosynthesisI got this question in an internship interview.I want to ask this question from Factors Affecting Photosynthesis in division Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Right CHOICE is (a) The leaf orientation of a plant AFFECTS PHOTOSYNTHESIS

Best explanation: The RATE of photosynthesis is affected by both external and internal factors. The photosynthetic rate is determined by a factor at sub-optimal level which is known as the LIMITING factor.

6.

Which of these is the C4 acid?(a) PEP(b) PGA(c) OAA(d) RuBisCOI had been asked this question in semester exam.My question is taken from Higher Plants Photosynthesis in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct option is (c) OAA

To EXPLAIN: The C4 acid has 4 CARBON atoms. It is oxaloacetic acid or OAA. It is the first stable product of carbon dioxide fixation in C4 PLANTS. PGA is a 3-carbon organic acid while PEP also has 3 carbon atoms.

7.

Which of these is the primary carbon dioxide acceptor in the Hatch and Slack pathway?(a) PEP(b) PGA(c) OAA(d) PEPcaseI have been asked this question in an interview.This question is from Higher Plants Photosynthesis in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct option is (a) PEP

The best I can explain: The primary carbon DIOXIDE ACCEPTOR in the Hatch and Slack pathway is PEP or phosphoenol pyruvate. PEP is present in the mesophyll CELLS. Phosphoenol pyruvate is a 3-carbon molecule.

8.

Which of the following is not related to the light reaction?(a) Also called Photochemical phase(b) Light absorption(c) Electron transport(d) Water splittingThe question was asked during an online interview.My question is taken from Higher Plants Photosynthesis topic in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct choice is (c) Electron transport

The explanation: Electron transport is not related to light REACTION. It is because light reaction is mainly based on photochemical processes like light absorption, water SPLITTING, the formation of ATP and NADPH, ETC. where electron transport is not included.

9.

How many numbers of chlorophyll are present in a photosynthetic unit?(a) 100 – 150(b) 90(c) 200 – 250(d) 300 – 350I had been asked this question by my school principal while I was bunking the class.This interesting question is from Pigments Involved in Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct option is (C) 200 – 250

The explanation is: In a photosynthetic UNIT, 200 – 250 NUMBER of chlorophylls are PRESENT. They are embedded in the thylakoids of chloroplast. It differs for different plant species as in algae, it is only 100 in number. The number of chlorophylls is BASED on their requirement and function.

10.

Which of these plants have the highest optimum temperature?(a) Tropical C3(b) Temperate C3(c) Tropical C4(d) Temperate C4This question was addressed to me in an interview.This question is from Factors Affecting Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer» CORRECT choice is (C) Tropical C4

Explanation: Tropical PLANTS have a HIGHER optimum temperature than temperate plants. C4 plants show a higher rate of photosynthesis at higher temperatures than C3 plants. Hence, tropical C4 plants have the highest optimum temperature.
11.

What happens when the incident light on a plant is excessive?(a) RuBP undergoes oxidation(b) Vascular bundles lose functionality(c) Mesophyll cells are destroyed(d) Chlorophyll breaks downThis question was posed to me in class test.I would like to ask this question from Factors Affecting Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct choice is (d) Chlorophyll breaks down

The BEST I can explain: Light is rarely a limiting factor for photosynthesis, but excess amount of light REACHING the photosynthetic parts of PLANT causes the breakdown of chlorophyll and hence, REDUCES the RATE of photosynthesis.

12.

Which of these is not a characteristic of C4 plants?(a) Toleration of higher temperatures(b) Response to high light intensities(c) Greater productivity of biomass(d) PhotorespirationThis question was addressed to me by my college professor while I was bunking the class.I'm obligated to ask this question of Higher Plants Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct ANSWER is (d) Photorespiration

Best explanation: C4 plants show some special ADAPTATIONS to survive extreme climate, such as TOLERANCE of HIGHER temperatures, response to high intensity LIGHTS, lack of photorespiration and greater productivity of biomass.

13.

Which of these are not present in mesophyll cells?(a) OAA(b) PEP carboxylase(c) PEPcase(d) RuBisCOI had been asked this question in quiz.This is a very interesting question from Higher Plants Photosynthesis in division Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The CORRECT option is (d) RuBisCO

Explanation: The mesophyll cells contain PEP or phosphoenol pyruvate, which is the primary CARBON dioxide acceptor. It also contains the enzyme PEPcase or PEP carboxylase. HOWEVER, it LACKS RuBisCO.

14.

How many turns of the Calvin cycle are required for the formation of 3 glucose molecules?(a) 15(b) 16(c) 12(d) 18I had been asked this question at a job interview.Origin of the question is Higher Plants Photosynthesis topic in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct option is (d) 18

To elaborate: The formation of one molecule of glucose requires the FIXATION of 6 carbon DIOXIDE molecules and hence six turns of the CALVIN CYCLE. Hence, 3 glucose molecules will require 18 turns of the cycle.

15.

What is the primary acceptor of CO2 in photosynthesis?(a) ATP(b) PGA(c) RuBP(d) OAAThis question was addressed to me in an interview.This interesting question is from Higher Plants Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer» CORRECT OPTION is (c) RuBP

The best explanation: The primary acceptor of carbon dioxide in photosynthesis is RuBP or RIBULOSE bisphosphate. Ribulose bisphosphate is a 5-carbon ketose SUGAR. It accepts carbon dioxide from the atmosphere.
16.

The harvesting systems are named in the order of their functioning sequence.(a) True(b) FalseI had been asked this question in an international level competition.This intriguing question comes from Higher Plants Photosynthesis in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct answer is (B) FALSE

The explanation: It is a false statement. Light-harvesting systems are named in the sequence of their discovery time and not based on the ORDER of their functioning sequence. PS I was found first and later PS II.

17.

The size of the chlorophyll molecule is Head: 20 x 20 A°, Tail: 15 A°(a) True(b) FalseThe question was asked during an online exam.This key question is from Pigments Involved in Photosynthesis in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The CORRECT CHOICE is (b) False

The explanation is: It is a wrong statement. They have a perfect body STRUCTURE with a HEAD and tail. The size of the chlorophyll molecule is Head: 15 x 15 A°, Tail: 20 A°. The size of the head is slightly smaller than the tail by 5 A°. They can be measured only in Angstrom unit because of their minute size.

18.

Why do stomata close during water shortage?(a) To reduce CO2 availability(b) To trap water(c) To increase metabolic activity(d) To increase the surface area of leavesThis question was posed to me in examination.Origin of the question is Factors Affecting Photosynthesis in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Right option is (a) To reduce CO2 availability

The best explanation: During water shortage in plants, the stomata close in ORDER to reduce the availability of CARBON dioxide for carbon dioxide FIXATION, which is the FIRST part of the CALVIN cycle of photosynthesis.

19.

What do the internal factors affecting photosynthesis dependent on?(a) External factors(b) Geographical area(c) Genetic predisposition(d) Species and sub-speciesThe question was asked in exam.My doubt stems from Factors Affecting Photosynthesis in division Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct option is (C) Genetic predisposition

To explain I would SAY: The genetic predisposition or the genetic make up of a plant is an INTERNAL factor that affects the rate of photosynthesis. The arrangement of genes present in the plant is expressed in a CERTAIN way in different plants.

20.

Which of these undergoes carboxylation during Calvin cycle?(a) NADPH(b) ATP(c) RuBP(d) PGAThis question was posed to me during an online exam.My question is taken from Higher Plants Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Right answer is (c) RUBP

Explanation: The most crucial step of the Calvin CYCLE is carboxylation, where carbon dioxide is fixated into a stable ORGANIC INTERMEDIATE. This organic intermediate is RuBP or RIBULOSE bisphosphate.

21.

Which of these is a 3-carbon organic acid?(a) PGA(b) BTCA(c) Citric acid(d) Acetic acidI had been asked this question in homework.My query is from Higher Plants Photosynthesis in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct choice is (a) PGA

The best explanation: PGA or 3-phosphoglyceric acid is a 3-carbon organic acid. CITRIC acid has 6 carbon ATOMS while ACETIC acid has 2 carbon atoms. PGA is a product of the carbon dioxide fixation stage of photosynthesis.

22.

How many molecules of NADPH are required for each Calvin cycle?(a) 3(b) 1(c) 4(d) 2I have been asked this question at a job interview.This is a very interesting question from Higher Plants Photosynthesis in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer» RIGHT option is (d) 2

For explanation: For EVERY carbon dioxide molecule used up in the Calvin CYCLE, 2 MOLECULES of NADPH are required. SIX cycles are required to produce one glucose molecule; hence 12 NADPH molecules are required to produce one molecule of glucose.
23.

Which of these compounds have 5 carbon atoms?(a) RuBP(b) OAA(c) PGA(d) ATPI have been asked this question in semester exam.The question is from Higher Plants Photosynthesis topic in division Photosynthesis in Higher Plants of Biology – Class 11

Answer» CORRECT answer is (a) RuBP

Explanation: RuBP or Ribulose bisphosphate is a 5-CARBON KETOSE sugar. It is the primary acceptor of carbon dioxide in photosynthesis. OAA is a 4-carbon organic acid while PGA is a 3-carbon organic acid.
24.

Which of these molecules is regenerated during the Calvin cycle?(a) NADPH(b) ATP(c) RuBP(d) CO2The question was asked during an online interview.I would like to ask this question from Higher Plants Photosynthesis in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct ANSWER is (c) RuBP

The explanation: Regeneration is the THIRD and final step of the Calvin cycle. In this step, the CO2 ACCEPTOR molecule RuBP or ribulose bisphosphate is regenerated. The regenerated RuBP is again used for the next Calvin cycle.

25.

Who discovered the first CO2 fixation product?(a) Anthony Van Leeuwenhoek(b) Robert Hooke(c) Melvin Calvin(d) Gregor MendelI got this question in my homework.This intriguing question comes from Higher Plants Photosynthesis in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct option is (c) Melvin Calvin

The best I can explain: Melvin Calvin has CONTRIBUTED greatly to PHOTOSYNTHESIS studies. The Calvin CYCLE was named after him. He used radioactive C-14 to discover the first CO2 fixation PRODUCT of photosynthesis, PGA.

26.

Who found out that the pigment chlorophyll is found in the chloroplast in plant cells?(a) Robert Hill(b) Hugo de Vries(c) Julius Von Sachs(d) C. Van NeilI have been asked this question during an interview.Query is from Pigments Involved in Photosynthesis topic in division Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct choice is (c) JULIUS Von Sachs

For explanation I WOULD say: Julius Von Sachs found out that the PIGMENT chlorophyll is present in chloroplast. Von Sachs in his EXPERIMENT found out glucose stored in the form of starch. This led to the DISCOVERY of pigment chlorophyll in the chloroplast.

27.

Which of these plants are grown in carbon dioxide enriched atmosphere?(a) Maize(b) Sugarcane(c) Tomato(d) MilletsI got this question in unit test.My query is from Factors Affecting Photosynthesis in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct option is (c) Tomato

Best explanation: Maize, sugarcane and millets are C4 PLANTS. Since C3 plants reach saturation at higher carbon DIOXIDE CONCENTRATIONS, plants such as tomatoes and bell peppers are grown in carbon dioxide enriched atmosphere.

28.

Which of these is not true regarding photorespiration?(a) ATP is not synthesized(b) 1 molecule of phosphoglycerate is formed(c) 1 molecule of PGA is formed(d) The active site of RuBisCO binds to oxygenI have been asked this question in class test.Enquiry is from Higher Plants Photosynthesis in division Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct option is (c) 1 molecule of PGA is FORMED

Best explanation: During the process of photorespiration, the active SITE of RuBisCO binds to oxygen. ATP and sugars are not formed. Instead of PGA, 1 molecule of phosphoglycerate and phosphoglycolate are formed.

29.

Which of these is a 2-carbon molecule?(a) Phosphoglycolate(b) OAA(c) PGA(d) Malic acidThis question was addressed to me during a job interview.The origin of the question is Higher Plants Photosynthesis topic in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct option is (a) Phosphoglycolate

The explanation is: Phosphoglycolate is a 2-carbon COMPOUND formed during the process of PHOTOSYNTHESIS. Malic ACID and oxaloacetic acid (OAA) are 4-carbon compounds while PGA is a 3-carbon compound.

30.

Which of the following is most sensitive to higher wavelengths of sunlight?(a) Photolysis(b) Chlorophyll(c) PS I(d) PS III had been asked this question in a national level competition.My question is from Higher Plants Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer» RIGHT answer is (c) PS I

Explanation: Photosystem I is most sensitive to higher wavelengths of SUNLIGHT. It is because its absorption maxima are 700nm which GIVES it more strength to CAPTURE wavelengths of light. PS II is not as much sensitive as PS I since it has absorption peak only at 680nm.
31.

CO2 assimilation during photosynthesis is of 3 types. True or false?(a) True(b) FalseI had been asked this question in semester exam.This interesting question is from Higher Plants Photosynthesis in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct choice is (b) False

The explanation is: Carbon dioxide assimilation during PHOTOSYNTHESIS is of two types depending UPON the first STABLE product of carbon dioxide fixation. The two types are the C3 PATHWAY and the C4 pathway.

32.

What is the atmospheric concentration of carbon dioxide?(a) 0.3 – 0.4%(b) 3 – 4%(c) 0.03 – 0.04%(d) 0.003 – 0.004%I had been asked this question by my college professor while I was bunking the class.This question is from Factors Affecting Photosynthesis in division Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Right option is (c) 0.03 – 0.04%

The best I can explain: The atmospheric CONCENTRATION of CARBON dioxide is 0.03 – 0.04%. Carbon dioxide concentration is an important EXTERNAL FACTOR that affects the rate of photosynthesis in all plants.

33.

Which of these cannot help us differentiate between C3 and C4 plants?(a) Carbon dioxide acceptor molecule(b) Presence of Kranz anatomy(c) Photorespiration(d) Number of chloroplastsThe question was posed to me in a job interview.Query is from Higher Plants Photosynthesis topic in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer» CORRECT CHOICE is (d) Number of chloroplasts

Easiest explanation: C4 plants DIFFER in various ways from C3 plants. They show Kranz ANATOMY. C4 plants LACK photorespiration but C3 plants have a high rate of photorespiration and they do not show Kranz anatomy.
34.

What is the most abundant enzyme in the world?(a) Papain(b) Alpha amylase(c) RuBisCO(d) Horse radish peroxidaseI have been asked this question in an interview for job.The above asked question is from Higher Plants Photosynthesis in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct option is (c) RUBISCO

To explain I would SAY: RuBisCO or Ribulose-1,5-bisphosphate carboxylase oxygenase is the most ABUNDANT ENZYME in the world. It catalyses the formation of 3PGA from RuBP and carbon dioxide.

35.

In which of these cells does the Calvin pathway occur in C3 plants?(a) Mesophyll cells(b) Bundle sheath cells(c) Epidermal cells(d) Sieve cellsThis question was posed to me by my college professor while I was bunking the class.The doubt is from Higher Plants Photosynthesis topic in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct option is (a) Mesophyll CELLS

To explain I would say: The CALVIN PATHWAY occurs in C3 plants in the mesophyll cells. In such plants, the first stable product of carbon DIOXIDE fixation is 3-PGA or 3-phosphoglyceric acid. In C4 plants, the Calvin cycle occurs in bundle sheath cells.

36.

How many molecules of ADP are produced as a result of six Calvin cycles?(a) 18(b) 24(c) 12(d) 32I got this question by my school teacher while I was bunking the class.My enquiry is from Higher Plants Photosynthesis topic in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The CORRECT CHOICE is (a) 18

The explanation: For every carbon DIOXIDE molecule USED up in the Calvin cycle, 3 molecules of ATP are required. Hence, 3 molecules of ADP are produced. For six Calvin cycles, 18 molecules of ADP are produced.

37.

Which of these is common to C3 and C4 plants?(a) OAA(b) PGA(c) Calvin cycle(d) PhotorespirationThis question was posed to me during an interview.This interesting question is from Higher Plants Photosynthesis in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct answer is (c) Calvin cycle

Explanation: In C3 PLANTS, the first stable product of carbon DIOXIDE fixation is 3-PGA or 3-phosphoglyceric acid. For C4 plants, it is OAA or oxaloacetic acid. C4 plants lack PHOTORESPIRATION. The Calvin cycle is common to both.

38.

How many molecules of NADP are produced as a result of six Calvin cycles?(a) 9(b) 18(c) 12(d) 24This question was posed to me in an international level competition.Question is from Higher Plants Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct CHOICE is (C) 12

The explanation is: For every carbon dioxide molecule used up in the Calvin cycle, 2 MOLECULES of NADPH are required. Hence, 2 molecules of NADP are produced. For six Calvin cycles, 12 molecules of NADP are produced.

39.

How much hydrogen protons are released by twelve water molecules?(a) 48(b) 6(c) 12(d) 24The question was asked during an interview for a job.My question is from Higher Plants Photosynthesis in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct choice is (d) 24

Explanation: By UNDERSTANDING the PHOTOLYSIS equation, one water molecule gives 2 hydrogen PROTONS. So, 12 water molecules will give 24 hydrogen protons.

40.

What is the empirical formula of chlorophyll b?(a) C55H70O6N4Mg(b) C55H72O5N4Mg(c) C55H79O7N4Mg(d) C55H80O6N5MgThis question was posed to me in an interview for job.I need to ask this question from Pigments Involved in Photosynthesis topic in division Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct answer is (a) C55H70O6N4Mg

Explanation: The empirical formula of CHLOROPHYLL b is C55H70O6N4Mg. They have 55 atoms of carbon, 70 atoms of hydrogen, 6 atoms of OXYGEN, 4 atoms of nitrogen and ONE atom MAGNESIUM. They are very microscopic and officially an accessory pigment.

41.

Regeneration during the Calvin cycle requires 3 ATP molecules. True or false?(a) True(b) FalseThe question was asked at a job interview.The query is from Higher Plants Photosynthesis topic in division Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Right option is (b) False

The best explanation: Regeneration is the third and final step of the Calvin CYCLE. In this step, the CO2 ACCEPTOR molecule RuBP is REGENERATED. Regeneration REQUIRES 1 ATP molecule for the purpose of phosphorylation.

42.

What is the first step of the Calvin pathway?(a) Regeneration(b) Reduction(c) CO2 fixation(d) Synthesis of sugarI had been asked this question in an online interview.Origin of the question is Higher Plants Photosynthesis topic in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct answer is (c) CO2 fixation

To explain: The FIRST step of the Calvin pathway or the Calvin CYCLE is the carbon dioxide fixation step. Carbon dioxide is fixed with the help of a carbon dioxide acceptor molecule, such as RuBP or PEP.

43.

What is the full form of PGA?(a) 2-phosphoglyceric acid(b) 2-phosphoglutamic acid(c) 3-phosphoglutamic acid(d) 3-phosphoglyceric acidThe question was asked by my college professor while I was bunking the class.My question comes from Higher Plants Photosynthesis topic in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Right option is (d) 3-phosphoglyceric ACID

The best explanation: The full form of PGA is 3-phosphoglyceric acid. 3-phosphoglyceric acid is a product of the CARBON DIOXIDE FIXATION stage of photosynthesis. 3-phosphoglyceric acid is a 3-carbon organic acid.

44.

In which process does carbon dioxide join photosynthesis?(a) Oxidation(b) PS I(c) Dark reaction(d) ReductionThis question was addressed to me during an interview.I'm obligated to ask this question of Higher Plants Photosynthesis topic in section Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct CHOICE is (C) Dark reaction

The explanation is: Carbon dioxide is entering the photosynthetic PATHWAY through dark reaction. RuBP reacts with CO2 to form the FIRST unstable carbon COMPOUND. So, here 6 molecules of CO2 are required to start dark reaction.

45.

In PS II, the last electron acceptor is ______(a) Plastocyanin(b) Ferredoxin(c) Cytochrome b6(d) Cytochrome b12The question was asked during a job interview.I would like to ask this question from Higher Plants Photosynthesis topic in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer»

The correct choice is (a) Plastocyanin

Easy EXPLANATION: Plastocyanin, which is a Cu protein is the last electron acceptor in PS II. It receives the electrons from cytochrome f and passes ONTO PS I. This is all BASED on non-cyclic photophosphorylation reaction.

46.

______ discovered the two-pigment system theory of light reaction?(a) Emerson(b) Hill(c) Arnon(d) MathewThis question was posed to me during an interview.Question is from Higher Plants Photosynthesis in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct choice is (a) EMERSON

To EXPLAIN I would say: Emerson was the scientist who PROPOSED the two-pigment THEORY of light reaction. Robert Hill was the scientist who found the light reaction or photochemical phase. Arnon coined the term phosphorylation.

47.

The reaction center is different in both the photosystems.(a) True(b) FalseThe question was posed to me in a job interview.The doubt is from Higher Plants Photosynthesis in section Photosynthesis in Higher Plants of Biology – Class 11

Answer» RIGHT option is (a) True

For explanation I would say: It is true since chlorophyll a has an absorption peak at 700 NM for PS I. For PS II, it has got an absorption maximum at 680 nm. Hence, the NAMES P700 and P680 were given for the reaction CENTERS.
48.

How many electrons and protons are produced during the photolysis of water?(a) 4 electrons and 3 protons(b) 1 electron and 2 protons(c) 3 electrons and protons(d) 4 electrons and 4 protonsThe question was asked in final exam.The above asked question is from Higher Plants Photosynthesis topic in portion Photosynthesis in Higher Plants of Biology – Class 11

Answer» CORRECT option is (d) 4 electrons and 4 protons

Explanation: Four electrons and four protons are produced at the END of the PHOTOLYSIS of water. Two MOLECULES of water GET converted into 4H^+ and 4e^– along with free oxygen. The ions used for this splitting is Mn^2+, Ca^2+, and Cl^–.
49.

Which pigment is absent in each photosystem?(a) One molecule of chlorophyll a(b) Two molecules of chlorophyll b(c) One molecule of chlorophyll b(d) One molecule of xanthophyllThis question was addressed to me in unit test.Origin of the question is Higher Plants Photosynthesis in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer»

Correct choice is (a) ONE molecule of CHLOROPHYLL a

Easy explanation: One molecule of chlorophyll a is absent in each PHOTOSYSTEM forming a light-harvesting SYSTEM also known as the antenna. These pigments make photosynthesis more efficient. The reaction center is formed by this one molecule of chlorophyll a.

50.

In which of these cells does the Calvin pathway occur in C4 plants?(a) Mesophyll cells(b) Bundle sheath cells(c) Epidermal cells(d) Sieve cellsI had been asked this question in semester exam.Query is from Higher Plants Photosynthesis in chapter Photosynthesis in Higher Plants of Biology – Class 11

Answer» RIGHT answer is (b) Bundle sheath cells

To ELABORATE: The Calvin pathway occurs in C4 plants in the bundle sheath cells. The bundle sheath cells are a CHARACTERISTIC of C4 plants. They surround the vascular bundles in layers. It is the SITE of Calvin cycle.