Physiology of Plants MCQs Part III

1) Protein is the respiratory substrate in
a) Seedling state
b) Anaerobic respiration
c) Protoplasmic respiration
d) Floating respiration

2) The number of oxygen atoms required for complete oxidation of pyruvic acid

a) 6
b) 12
c) 3
d) 8

3) In bacteria the site for respiration is the
a) Cytoplasm
b) Mesosome
c) Episome
d) Plasmid

4) The production of alcohol by Yeast fermentation is an …… process
a) Anaerobic
b) Aerobic
c) Light dependent
d) Both A and C

5) The differences between photophosphorylation (PP) and oxidative phosphorylation
(OP) is

a) In PP, synthesis is of ATP while in OP it is of ADP
b) In PP, oxygen is evolved while in OP oxygen is taken up
c) Both cannot take place in light
d) PP can take place in green leaves while OP cannot occur in green stems.

6) Where do we observe both photosynthesis and respiration?
a) Fungi
b) Viruses
c) Bacteria
d) Green plants

7) In glycolysis, the enzyme enolase produces
a) Phosphoglyceric acid
b) Phosphoenol pyruvate
c) Phosphoglyceraldehyde
d) Pyruvate

8) Which can readily respire without oxygen?
a) Anabaena
b) Saccharomyces
c) Mushroom
d) Fish

9) Green plants kept in the light produce ATP from glucose. The process is
a) Photophosphorylation
b) Glycolysis
c) TCA cycle
d) Oxidative phosphorylation

10) One  yields
a) 2 ATP
b) 3 ATP
c) 12 ATP
d) 6 ATP

11) Absorptive nutrition is
a) Holophytic nutrition
b) Saprotrophic nutrition
c) Parasitic nutrition
d) Both B and C

12) Autotrophic nutrition includes
a) Chemosynthesis
b) Photosynthesis
c) Both A and B
d) Ingestive nutrition

13) Nutrition of procaryotes is
a) Autotrophy
b) Chemoheterotrophy
c) Both A and B
d) Phagotrophy

14) A microbe which is harmful and enters the human body to cause disease is called a
a) Saprophyte
b) Symbiont
c) Pathogen
d) Commensal

15) A facultative saprophyte is
a) Always a parasite
b) A parasite but can be a saprophyte
c) A saprophyte but acquires a parasitic mode
d) Always a saprophyte

16) A facultative parasite is one which
a) Is normally a parasite but can also become a saprophyte
b) Always requires dead organic matter
c) Always requires a living host
d) Is normally a saprophyte but can also become a parasite

17) Fungal hyphae penetrate the hard cell walls of their hosts with the help of
a) Sugar exudates
b) Hormones
c) Enzymes
d) Sharp tips

18) When two host species are required for the completion of life cycle of a parasitic fungus, this condition is described as
a) Heteroecious
b) Heterokaryotic
c) Autoecious
d) Autotrophic

19) All fungi are always
a) Parasites
b) Autotrophs
c) Heterotrophs
d) Saprophytes

20) The hyphal system is called a mycelium in
a) Fungi
b) Pteridophytes
c) Algae
d) Bryophytes

21) Organisms which obtain their food from non-living material in their environment are called
a) Parasites
b) Saprophytes
c) Epiphytes
d) Sporophytes

22) In the nitrogen cycle nitrite is converted to nitrates by
a) Nitrobacter
b) Azotobacter
c) Rhizobium
d) Nitrosomonas

23) The conservation of organic nitrogenous compounds into ammonium compounds is called
a) Denitrification
b) Aminization
c) Nitrification
d) Ammonification

24) The correct sequence in protein synthesis is

25) Bacteroids are
a) Nitrosomonas bacteria in soil
b) the enlarged non-motile cellular bacteria, Rhizobium leguminasorum, in the root nodules of legumes
c) A bacterial cell infected with viruses
d) A mobile bacterium

26) The enzyme responsible for atmospheric nitrogen fixation is: Or the key enzyme
in biological
fixation is

a) Oxygenase
b) Carboxylase
c) Hydrogenase
d) Nitrogenase

27) Which of the following elements is essential or involved in
metabolism, in the reduction of nitrates?

a) Zn
b) B
c) Mn
d) Mo

28) Which pigment is essential for nitrogen fixation by leguminous plants?
a) Phycoerythrin
b) Anthocyanin
c) Leghaemoglobin
d) Phycocyanin

29) Proteins are made up of
a) Amino acids
b) Nucleic acids
c) Sugars
d) Fatty acids

30) The symbolic fixation of atmospheric nitrogen in the root nodules of
legume crops is brought about by

a) Mucor
b) Rhizopus
c) Rhizobium
d) Mycobacterium

31) An example of a photosynthetic anaerobic non-symbiotic nitrogen fixing
bacterium is

a) Rhodospirilium
b) Rhizobium
c) Bacillus
d) Azotobactor

32) All of the following contribute to the available nitrogen compounds
in the soil except:

a) Liming
b) Animal remains
c) Plant remains
d) Thunder storm

33) Which one of the following can fix atmospheric nitrogen as a free
living organism?

a) Ulothrix
b) Vancheria
c) Nostoc
d) Rhizobium

34) The activity of nitrogenase in nitrate-fixing micro-organisms can be
seen when

a) Ethane is converted to methane
b) Methane is converted to ethane
c) Ethylene is converted to acetylene
d) Acetylene is converted or reduced to ethylene

35) The largest reservoir of nitrogen on earth is
a) The air
b) The soil
c) The oceans
d) Granite rocks

36) The plants that have a mutualistic relation with nitrogen fixing bacteria
receive from the bacteria

a) Nitrite
b) Amino acid
c) Ammonium
d) Nitrate

37) Organisms that fix nitrogen in aquatic habitats are
a) Brown algae
b) Cyanobacteria
c) Green algae
d) Protozoa

38) Nitrogen fixation by bacteria requires the following enzyme and pigment respectively
a) Nitrogenase and leghaemoglobin
b) Decarboxylase and haemoglobin
c) Nitro dioxidase and chlorophyll
d) Nitrogen deaminase and xanthophyll

39) Plants that have a mutualistic relation with nitrogen fixing bacteria
provide the bacteria with

b) Sugars
c) Enzymes
d) Nitrite

40) The nodules in a plant root where nitrogen fixing bacteria live arise from
the cells of the

a) Endodermis
b) Epidermis
c) Cortex
d) Vascular cylinder

41) Normally the multiplication factor for converting nitrogen into
proteins is

a) 3.57
b) 3.12
c) 6.25
d) 7.14

42) Which of the following is the most limiting factor of nitrification
in the soil?

a) Tillage
b) Soil reaction (pH)
c) Moisture
d) Temperature

43) A recently discovered non-leguminous
fixing bacterium is

a) Azotobacter
b) Spirulina
c) Rhizobium
d) Rhodospirillum

44) Most of the plants obtain nitrogen from the soil in the form

a) Nitrates
b) Nitrites
c) Nitric acid
d) Free nitrogen gas

45) The nitrogen present in the atmosphere is
a) Of no use to the plants
b) Directly utilized by plants
c) Injurious to the plants
d) Utilized by plants through microorganisms

46) Molybdenum plays a large role in
a) Carbon fixation
b) Chromosome condensation
c) Nitrogen fixation
d) Promoting flowering

47) Which of the following cannot fix atmospheric nitrogen directly?
a) Castor
b) Bean
c) Pea
d) Horse gram

48) The following is an aerobic, free living nitrogen fixing soil

a) Rhizobium
b) Clostridium
c) Frankium
d) Azotobacter

49) The cells of the root nodules in legumes differ from other vegetative
cells in

a) Being living
b) Having endoplasmic reticulum
c) Being tetraploid
d) Absence of cell division

50) What is the order in nitrogen assimilation?

51) The nitrogen of the atmosphere cannot be absorbed by plants directly

a) the concentration of nitrogen in the atmosphere is low
b) Plants do not need nitrogen to perform the physiological process properly
c) It will stop all physiological process
d) Nitrogen though present in high concentration in the gaseous form in the atmosphere is in an inert form

52) Nitrogenase converts
a) Nitrogen into ammonia
b) Ammonia into nitrite
c) Nitrite into nitrate
d) Nitrate into nitrogen

53) Proteins essentially contain
a) Carbon, Nitrogen, Hydrogen and Sulphur
b) Carbon, Nitrogen, Oxygen and Sulphur
c) Carbon, Nitrogen, Hydrogen and oxygen
d) Nitrogen, Hydrogen Oxygen and Sulphur

54) The bacteria that change protein to ammonia in the nitrogen cycle are
a) Denitrifying bacteria
b) Nitrate bacteria
c) Nitrogen fixing bacteria
d) Ammonifying bacteria (Decay bacteria)

55) In nature the main organisms which take part in the nitrogen cycle

a) Saprophytic flowering plants
b) Parasitic fungi
c) Legume plants
d) Bacteria

56) The members of the bean family are of particular importance in a crop
rotation programme primarily because

a) They have nitrogen fixing bacteria associated in their roots
b) They add nitrates to the soil
c) They provide green manure
d) They manufacture nitrogenous compounds

57) Without adding nitrogenous manure a good yield of rice crop can
be obtained because

a) They require minute quantities of nitrogen
b) There are nitrogen fixing algae in rice fields
c) Their roots have nitrogen fixing bacteria
d) Rice plants do not require nitrogen

58) A crop plant that can grow well in nitrogen deficient soils
without the addition of manure is

a) Helianthus annus
b) Allium sativum
c) Cajanus cajan
d) Gossypium herbaceum

59) Rotation of crops is practiced in agriculture because
a) It kills harmful bacteria of the soil
b) It decreases the nitrogen content of the soil
c) It increases the water content of the soil
d) It increases the nitrogen content of the soil

60) Nitrogen can be fixed in the soil economically
a) Growing leguminous plants
b) Increasing bacteria by ploughing
c) Adding nitrogen fixing bacteria
d) Adding humus

61) Soil nitrate is more likely to leach than ammonium due to its
a) Abundance
b) Being useless to soil flora
c) Negative charge
d) Small size

62) Nitrate is converted into nitrogen by
a) Denitrifying bacteria
b) Nitrifying bacteria
c) Ammonifying bacteria

63) Nitrification in the soil involves the conversion of
a) Nitrates to nitrites
b) Nitrate to nitrogen gas
c) Nitrogen to nitrates
d) Ammonia to nitrates

64) Root nodules for nitrogen fixation in non-leguminous trees are
produced by species of the genus

a) Rhizobium
b) Azotobacter
c) Thiobacillus
d) Frankia

65) Nitrogen is an important constituent of
a) Proteins
b) Lipids
c) Carbohydrates
d) Polyphosphates

66) Non-symbiotic nitrogen fixers are
a) Pseudomonas
b) Azotobacter
c) Blue green algae
d) Soil fungi

67) Which one of the following statements is correct?
a) Legumes are incapable of fixing nitrogen
b) Legumes fix nitrogen only through the specialized bacteria that live in their roots
c) Legumes fix nitrogen independently or the specialized bacteria that live in their roots
d) Legumes fix nitrogen only through specialized bacteria that live in their leaves

68) Which one of the following species does not have the ability
to fix atmospheric nitrogen?

a) Spirogyra
b) Azotobactor
c) Nostoc
d) Anabaena

69) The bacterium capable of anaerobic
fixation is known as

a) Clostridium
b) Bacillus
c) Azotobacter
d) Rhizobium

70) The main feature of leghaemoglobin is that it
a) Promotes oxygen availability to nodules
b) Generates ATP for nitrogen fixation
c) Generates hydrogen ions for ammonia form
d) Scavenges oxygen

71) The bacterial genera carrying out nitrification, nitration,
asymbiotic and symbiotic nitrogen fixation respectively are

a) Nitrobacter, Nitrosomonas, Azotobacter and Rhizobium
b) Nitrosomonas, Nitrobacter, Azotobacter and Rhizobium
c) Rhizobium, Azotobacter, Nitrosomonas and Nitrobacter
d) Nitrosomonas, Nitrobacter and Rhizobium

72) The organic acid which plays the key role in the synthesis
of amino acids is

b) Oxaloacetic acid
c) Pyruvic acid
d) Malic acid

73) Which of the following microbes develops nodules on the surface of
its leaves and fixes nitrogen?

a) Klebsiella
b) Azotobacter
c) Nitrosomonas
d) Pseudomonas

74) Azotobacter and Bacillus polymixa are examples of
a) Diseases causing bacteria
b) Non-symbiotic nitrogen fixers
c) Symbiotic nitrogen fixers
d) Ammonifying bacteria

75) The type of bonds present in the secondary structure of proteins

a) Peptide and hydrophobic bonds
b) Peptide and hydrogen bonds
c) Peptide and disulphide bonds
d) Hydrogen and ionic bonds

76) The role of nitrifying bacteria in the nitrogen cycle is to
a) Convert ammonia into nitrogen
b) Fix atmospheric nitrogen
c) Convert ammonia into nitrates
d) Convert amino acids into ammonia

77) The source of ATP for symbiotic nitrogen fixation in root nodules

a) Ferredoxin
b) Pyruvate
c) Malate
d) Hydrogenase

78) The function of haemoglobin in the root nodules of leguminous plants

b) To induce ATP synthesis

79) Pseudomonas is an important component of nitrogen cycle. It
a) Changes ammonium nitrogen to nitrate state
b) Fixes elemental nitrogen
c) Produces elemental nitrogen
d) Transfers nitrogen

80) Nitrogen fixation occurs in
a) Some herbaceous plants and legumes
b) Legumes and some bacteria
c) Some bacteria, cyanobacteria and legumes
d) All green plants

81) Vestigial stomata are found in
a) Xerophytes
b) Floating hydrophytes
c) Submerged hydrophytes
d) Mesophytes

82) Which side of a bifacial (dorsiventral) leaf possesses more stomata?
a) the adaxial side
b) the abaxial side
c) the tip and margins only
d) a and b equally

83) A leaf which possesses stomata exclusively on its upper side is the
a) Oat type
b) Mulberry type
c) Lotus type
d) Cactus type

84) The largest number of chloroplasts in the leaf is in the
a) Spongy tissue
b) Palisade tissue
c) Guard cells
d) Bundle sheath cells

85) In older woody tissue, gaseous exchange takes place through the
a) Lenticels
b) Hydathodes
c) Stomata
d) Aerenchyma

When a bottle of perfume is placed at one corner of a room and the lid opened, the scent spreads all over the room after some time. This happens by the process of

a) Plasmolysis
b) Diffusion
c) Transpiration
d) Endosmosis

87) The movement of molecules of gases, liquids and solutes from a region of higher concentration to a region of lower concentration is termed as
a) Diffusion
b) Evaporation
c) Transpiration
d) Osmosis

88) In terms of permeability, the cell wall and plasmalemma are
a) Permeable and differentially permeable respectively
b) Both differentially permeable
c) Both semi-permeable
d) Semi-permeable and differentially permeable

89) The plasma membrane controls the
a) Passage of water only
b) Passage of water and solutes in and out of the cell
c) Passage of water and solutes into the cell
d) Movement of cell contents out of the cell

90) Water moves across a selectively permeable membrane from
a) The region of higher water potential to the region of lower water potential
b) A lower water concentration to higher water concentration
c) Higher solute concentration to lower solute concentration
d) Region of higher osmotic potential to region of lower osmotic potential

91) Osmosis is defined as
a) The flow of solvent molecules from a region of higher concentration to lower concentration through a semi-permeable membrane
b) The flow of low concentration liquids
c) The flow of solvent molecules from a higher concentration to a lower concentration region
d) The flow of solvent molecules from a lower concentration to higher concentration region

92) The maximum diffusion pressure is that of
a) a molal solution
b) a molar solution
c) a normal solution
d) A pure solvent

93) The plasma membrane is
a) Impermeable
b) A selective barrier
c) A non-selective barrier
d) Made up of cellulose

94) Purple cabbage leaves do not lose their colour in cold water but do so in boiling water because
a) The plasma membrane of the cell is damaged in boiling water
b) Hot water can enter the cells readily
c) The pigment is not soluble in cold water
d) The cell wall is killed in boiling water

95) Selective permeability is a characteristic of the
a) Cell wall
b) Cell membrane
c) Middle lamella
d) Cytoplasm

96) When beetroot cylinders are washed and then placed in cold water, anthocyanin does not come out. It indicates most likely that the plasma membrane is
a) Differentially permeable to anthocyanin
b) Dead structure
c) Impermeable to anthocyanin
d) Permeable to anthocyanin

97) The process of selective transmission through a semipermeable membrane is termed (or selective permeability identifies the process of)
a) Diffusion
b) Imbibition
c) Osmosis
d) Plasmolysis

98) In the process of osmosis
a) Both the protoplasm and the cell wall act as a single layer
b) Only the protoplast acts as a single layer
c) Only the cell membrane acts as a single layer
d) None of the above

99) Osmosis is the property of
a) Solutes
b) Solutions
c) A semipermeable membrane
d) A solvent

100) Which of the following statements is wrong?
a) The membrane is readily permeable to water but slowly permeable to dissolved salts
b) The plasma membrane is impermeable to sugars and other foods
c) Killing of the cell destroys the cell wall but not the cell membrane
d) The movement of food into the cell and its vacuole may be by active transport



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