Microbiology Questions and Answers – Morphology and Fine Bacteria Structure – Size, Shape and Arrangement of Bacterial Cells.
1. In the classification of bacteria according to shape,which among the following refer to cuboidal arrangement of bacterial cells?
a) Tetrads
b) Staphylococci
c) Sarcinae
d) Streptococci
View Answer
a) Tetrads
b) Staphylococci
c) Sarcinae
d) Streptococci
View Answer
Answer: c
Explanation: In Sarcinae group of bacteria, the cells divide in three planes, in a regular pattern, producing a cuboidal arrangement of cells. In Staphylococci, cells divide in three planes, in an irregular pattern,producing bunches of cocci.
Explanation: In Sarcinae group of bacteria, the cells divide in three planes, in a regular pattern, producing a cuboidal arrangement of cells. In Staphylococci, cells divide in three planes, in an irregular pattern,producing bunches of cocci.
2. Which group of bacteria among the following have the largest area of contact?
a) Palisades
b) Trichomes
c) Streptobacilli
d) Diplobacilli
View Answer
a) Palisades
b) Trichomes
c) Streptobacilli
d) Diplobacilli
View Answer
Answer: b
Explanation: Trichomes are similar to chains but have a much larger area of contact between the adjacent cells whereas in palisade arrangement, the cells are ind side by side at angles to one another.
Explanation: Trichomes are similar to chains but have a much larger area of contact between the adjacent cells whereas in palisade arrangement, the cells are ind side by side at angles to one another.
3. Which among the following are “Spirochetes”?
a) Spirillum volutans
b) Corynebacterium diphtheriae
c) Streptomyces sp.
d) Treponema pallidum
View Answer
a) Spirillum volutans
b) Corynebacterium diphtheriae
c) Streptomyces sp.
d) Treponema pallidum
View Answer
Answer: d
Explanation: Spirochetes are flexible and can twist and contort their shape, whereas spirilla are relatively rigid. Treponema palldium belong to the spirochetes group and Spirillum volutans belong to the spirilla group.
Explanation: Spirochetes are flexible and can twist and contort their shape, whereas spirilla are relatively rigid. Treponema palldium belong to the spirochetes group and Spirillum volutans belong to the spirilla group.
4. What is the approximate size of the bacterial cell?
a) 2mm in diameter
b) 1mm in diameter
c) 2 micrometer in diameter
d) 0.5 to 1.0 micrometer in diameter
View Answer
a) 2mm in diameter
b) 1mm in diameter
c) 2 micrometer in diameter
d) 0.5 to 1.0 micrometer in diameter
View Answer
Answer: d
Explanation: Bacteria are very small, most being approximately 0.5 to 1.0 micrometer in diameter.This is the reason why they cannot be seen by naked eyes and can be observed under the microscope.
Explanation: Bacteria are very small, most being approximately 0.5 to 1.0 micrometer in diameter.This is the reason why they cannot be seen by naked eyes and can be observed under the microscope.
5. When rod shaped bacteria appears in pairs,it is known as?
a) Diplobacilli
b) Streptobacilli
c) Diplococci
d) Staphylococci
View Answer
a) Diplobacilli
b) Streptobacilli
c) Diplococci
d) Staphylococci
View Answer
Answer: a
Explanation: When bacilli occur in pairs, it is known as diplobacilli but when they form chains it is known as streptobacilli. Cocci are spherical shaped bacteria and not rod shaped.
Explanation: When bacilli occur in pairs, it is known as diplobacilli but when they form chains it is known as streptobacilli. Cocci are spherical shaped bacteria and not rod shaped.
6. Surface area/volume ratio of bacteria is exceedingly low compared to the same ratio for larger organisms of similar shape.
a) True
b) False
View Answer
a) True
b) False
View Answer
Answer: b
Explanation: Due to the small size of microorganisms, the surface area/volume ratio of bacteria is exceedingly high compared to the same ratio for larger organisms of similar shape. A relatively large surface through which nutrients can enter ( or waste products leave) compared to a small volume of cell substance to be nourished accounts for the unusually high rate of growth and metabolism of bacteria.
Explanation: Due to the small size of microorganisms, the surface area/volume ratio of bacteria is exceedingly high compared to the same ratio for larger organisms of similar shape. A relatively large surface through which nutrients can enter ( or waste products leave) compared to a small volume of cell substance to be nourished accounts for the unusually high rate of growth and metabolism of bacteria.
7. Bacteria with less than a complete twist or comma shaped is known as?
a) spirilla
b) helical
c) vibrioid
d) spirochetes
View Answer
a) spirilla
b) helical
c) vibrioid
d) spirochetes
View Answer
Answer: c
Explanation: Bacteria with less than a complete twist or turn have a vibrioid shape,whereas those with one or more complete turns have a helical shape. Spirilla are rigid helical bacteria whereas spirochetes are highly flexible.
Explanation: Bacteria with less than a complete twist or turn have a vibrioid shape,whereas those with one or more complete turns have a helical shape. Spirilla are rigid helical bacteria whereas spirochetes are highly flexible.
8. Which of the following are functions of stalk?
a) nutrient absorption
b) motility
c) attachment of the cells to surfaces
d) human infection
View Answer
a) nutrient absorption
b) motility
c) attachment of the cells to surfaces
d) human infection
View Answer
Answer: c
Explanation: Stalk are mainly nonliving ribbonlike or tubular appendages that are excreted by the cell. These stalks aid in attachment of the cells to surfaces.
Explanation: Stalk are mainly nonliving ribbonlike or tubular appendages that are excreted by the cell. These stalks aid in attachment of the cells to surfaces.
1. Bacteria having cluster of flagella at both poles of cells are known as?
a) Lophotrichous
b) Peritrichous
c) Amphitrichous
d) Monotrichous
View Answer
a) Lophotrichous
b) Peritrichous
c) Amphitrichous
d) Monotrichous
View Answer
Answer: c
Explanation: In amphitrichous, flagella occur either singly or in clusters at both cell poles. Lophotrichous refers to a cluster of polar flagella, peritrichous is surrounded by lateral flagella and monotrichous is for a single polar flagella.
Explanation: In amphitrichous, flagella occur either singly or in clusters at both cell poles. Lophotrichous refers to a cluster of polar flagella, peritrichous is surrounded by lateral flagella and monotrichous is for a single polar flagella.
Microbiology Questions and Answers – Morphology and Fine Bacteria – Structures External to the Cell Wall
This set of Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Morphology and Fine Bacteria – Structures External to the Cell Wall”.
1. Bacteria having cluster of flagella at both poles of cells are known as?
a) Lophotrichous
b) Peritrichous
c) Amphitrichous
d) Monotrichous
View Answer
a) Lophotrichous
b) Peritrichous
c) Amphitrichous
d) Monotrichous
View Answer
Answer: c
Explanation: In amphitrichous, flagella occur either singly or in clusters at both cell poles. Lophotrichous refers to a cluster of polar flagella, peritrichous is surrounded by lateral flagella and monotrichous is for a single polar flagella.
Explanation: In amphitrichous, flagella occur either singly or in clusters at both cell poles. Lophotrichous refers to a cluster of polar flagella, peritrichous is surrounded by lateral flagella and monotrichous is for a single polar flagella.
2. Salmonella typhi has which type of flagella arrangement?
a) Amphitrichous
b) Peritrichous
c) Monotrichous
d) Lophotrichous
View Answer
b) Peritrichous
c) Monotrichous
d) Lophotrichous
View Answer
Answer: b
Explanation: Salmonella typhi has peritrichous type of flagella arrangement. In peritrichous, the bacteria is surrounded by lateral flagella.
Explanation: Salmonella typhi has peritrichous type of flagella arrangement. In peritrichous, the bacteria is surrounded by lateral flagella.
3. The L Ring in a Gram-Negative bacterium flagella is associated with_________
a) Peptidogycan
b) Outer Membrane
c) Cytoplasmic Membrane
d) Cell Membrane
View Answer
a) Peptidogycan
b) Outer Membrane
c) Cytoplasmic Membrane
d) Cell Membrane
View Answer
Answer: b
Explanation: The flagella in Gram-Negative bacteria has four basal rings. The L Ring of flagella is associated with the outer membrane. The P ring is associated with the peptidoglycan layer and both the M and S rings are associated with the cytoplasmic membrane.
Explanation: The flagella in Gram-Negative bacteria has four basal rings. The L Ring of flagella is associated with the outer membrane. The P ring is associated with the peptidoglycan layer and both the M and S rings are associated with the cytoplasmic membrane.
4. Which among the following acts as a transport protein for protons in flagellar motion?
a) fli protein
b) cGMP
c) atp
d) mot protein
View Answer
a) fli protein
b) cGMP
c) atp
d) mot protein
View Answer
Answer: d
Explanation: The proton binds to the Mot protein and this changes the conformation of Mot protein. It results in releasing the ring and helps in flagellar motion. The fli protein helps in changing the direction of flagella.
Explanation: The proton binds to the Mot protein and this changes the conformation of Mot protein. It results in releasing the ring and helps in flagellar motion. The fli protein helps in changing the direction of flagella.
5. F pilus has a major role as___________
a) motility of the cell
b) port of entry of genetic material during mating
c) attachment to host cell
d) human infection
View Answer
a) motility of the cell
b) port of entry of genetic material during mating
c) attachment to host cell
d) human infection
View Answer
Answer: b
Explanation: Pili are hollow,filamentous appendages that are thinner and shorter.They do not function in motility and have other different functions.One type known as F plus or sex plus serves as the port of entry of genetic material during bacterial mating.
Explanation: Pili are hollow,filamentous appendages that are thinner and shorter.They do not function in motility and have other different functions.One type known as F plus or sex plus serves as the port of entry of genetic material during bacterial mating.
6. Prosthecae helps in __________
a) motility
b) nutrient absorption and attachment to surfaces
c) human infection
d) protection from environment
View Answer
a) motility
b) nutrient absorption and attachment to surfaces
c) human infection
d) protection from environment
View Answer
Answer: b
Explanation: Prosthecae increases the surface area of the cells for nutrient absorption, which is advantageous in dilute environments. Some prosthecate bacteria have an adhesive substance at the end of a prostheca that aids in attachment to surfaces.
Explanation: Prosthecae increases the surface area of the cells for nutrient absorption, which is advantageous in dilute environments. Some prosthecate bacteria have an adhesive substance at the end of a prostheca that aids in attachment to surfaces.
7. The capsule of Klebsiella pneumoniae is composed of heteropolysaccharides.
a) True
b) False
View Answer
a) True
b) False
View Answer
Answer: a
Explanation: Heteroploysaccharides are usually synthesized from sugar precursors that are activated within the cell, attached to a lipid carrier molecule, transported across the cytoplasmic membrane and polymerized outside the cell. The capsule of Klebsiella pneumoniae is an example of heteropolysaccharides.
Explanation: Heteroploysaccharides are usually synthesized from sugar precursors that are activated within the cell, attached to a lipid carrier molecule, transported across the cytoplasmic membrane and polymerized outside the cell. The capsule of Klebsiella pneumoniae is an example of heteropolysaccharides.
Microbiology Questions and Answers – Morphology and Fine Bacteria – Structures External to the Cell Wall
This set of Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Morphology and Fine Bacteria – Structures External to the Cell Wall”.
1. Bacteria having cluster of flagella at both poles of cells are known as?
a) Lophotrichous
b) Peritrichous
c) Amphitrichous
d) Monotrichous
View Answer
a) Lophotrichous
b) Peritrichous
c) Amphitrichous
d) Monotrichous
View Answer
Answer: c
Explanation: In amphitrichous, flagella occur either singly or in clusters at both cell poles. Lophotrichous refers to a cluster of polar flagella, peritrichous is surrounded by lateral flagella and monotrichous is for a single polar flagella.
Explanation: In amphitrichous, flagella occur either singly or in clusters at both cell poles. Lophotrichous refers to a cluster of polar flagella, peritrichous is surrounded by lateral flagella and monotrichous is for a single polar flagella.
2. Salmonella typhi has which type of flagella arrangement?
a) Amphitrichous
b) Peritrichous
c) Monotrichous
d) Lophotrichous
View Answer
b) Peritrichous
c) Monotrichous
d) Lophotrichous
View Answer
Answer: b
Explanation: Salmonella typhi has peritrichous type of flagella arrangement. In peritrichous, the bacteria is surrounded by lateral flagella.
Explanation: Salmonella typhi has peritrichous type of flagella arrangement. In peritrichous, the bacteria is surrounded by lateral flagella.
3. The L Ring in a Gram-Negative bacterium flagella is associated with_________
a) Peptidogycan
b) Outer Membrane
c) Cytoplasmic Membrane
d) Cell Membrane
View Answer
a) Peptidogycan
b) Outer Membrane
c) Cytoplasmic Membrane
d) Cell Membrane
View Answer
Answer: b
Explanation: The flagella in Gram-Negative bacteria has four basal rings. The L Ring of flagella is associated with the outer membrane. The P ring is associated with the peptidoglycan layer and both the M and S rings are associated with the cytoplasmic membrane.
Explanation: The flagella in Gram-Negative bacteria has four basal rings. The L Ring of flagella is associated with the outer membrane. The P ring is associated with the peptidoglycan layer and both the M and S rings are associated with the cytoplasmic membrane.
4. Which among the following acts as a transport protein for protons in flagellar motion?
a) fli protein
b) cGMP
c) atp
d) mot protein
View Answer
a) fli protein
b) cGMP
c) atp
d) mot protein
View Answer
Answer: d
Explanation: The proton binds to the Mot protein and this changes the conformation of Mot protein. It results in releasing the ring and helps in flagellar motion. The fli protein helps in changing the direction of flagella.
Explanation: The proton binds to the Mot protein and this changes the conformation of Mot protein. It results in releasing the ring and helps in flagellar motion. The fli protein helps in changing the direction of flagella.
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5. F pilus has a major role as___________
a) motility of the cell
b) port of entry of genetic material during mating
c) attachment to host cell
d) human infection
View Answer
a) motility of the cell
b) port of entry of genetic material during mating
c) attachment to host cell
d) human infection
View Answer
Answer: b
Explanation: Pili are hollow,filamentous appendages that are thinner and shorter.They do not function in motility and have other different functions.One type known as F plus or sex plus serves as the port of entry of genetic material during bacterial mating.
Explanation: Pili are hollow,filamentous appendages that are thinner and shorter.They do not function in motility and have other different functions.One type known as F plus or sex plus serves as the port of entry of genetic material during bacterial mating.
6. Prosthecae helps in __________
a) motility
b) nutrient absorption and attachment to surfaces
c) human infection
d) protection from environment
View Answer
a) motility
b) nutrient absorption and attachment to surfaces
c) human infection
d) protection from environment
View Answer
Answer: b
Explanation: Prosthecae increases the surface area of the cells for nutrient absorption, which is advantageous in dilute environments. Some prosthecate bacteria have an adhesive substance at the end of a prostheca that aids in attachment to surfaces.
Explanation: Prosthecae increases the surface area of the cells for nutrient absorption, which is advantageous in dilute environments. Some prosthecate bacteria have an adhesive substance at the end of a prostheca that aids in attachment to surfaces.
7. The capsule of Klebsiella pneumoniae is composed of heteropolysaccharides.
a) True
b) False
View Answer
a) True
b) False
View Answer
Answer: a
Explanation: Heteroploysaccharides are usually synthesized from sugar precursors that are activated within the cell, attached to a lipid carrier molecule, transported across the cytoplasmic membrane and polymerized outside the cell. The capsule of Klebsiella pneumoniae is an example of heteropolysaccharids.
Explanation: Heteroploysaccharides are usually synthesized from sugar precursors that are activated within the cell, attached to a lipid carrier molecule, transported across the cytoplasmic membrane and polymerized outside the cell. The capsule of Klebsiella pneumoniae is an example of heteropolysaccharids.
8. When a bacteria swim towards a chemical, it is termed as__________
a) positive chemotaxis
b) phototaxis
c) negative chemotaxis
d) magnetotaxis
View Answer
a) positive chemotaxis
b) phototaxis
c) negative chemotaxis
d) magnetotaxis
View Answer
Answer: a
Explanation: When a bacteria swims towards or away from chemical compounds, the phenomenon is known as bacterial chemotaxis.Swimming towards a chemical is termed as positive chemotaxis; swimming away is negative chemotaxis.
Explanation: When a bacteria swims towards or away from chemical compounds, the phenomenon is known as bacterial chemotaxis.Swimming towards a chemical is termed as positive chemotaxis; swimming away is negative chemotaxis.
9. Which type of force drives the flagellar motion?
a) Protonmotive force
b) ATP driven
c) Protonmotive and ATP driven
d) No protonmotive nor ATP driven
View Answer
a) Protonmotive force
b) ATP driven
c) Protonmotive and ATP driven
d) No protonmotive nor ATP driven
View Answer
Answer: a
Explanation: It is found that flagellar motor is driven by the protonmotive force, i.e., the force derived from the electrical potential and the hydrogen-ion gradient across the cytoplasmic membrane.
Explanation: It is found that flagellar motor is driven by the protonmotive force, i.e., the force derived from the electrical potential and the hydrogen-ion gradient across the cytoplasmic membrane.
Microbiology Questions and Answers – Morphology and Fine Bacteria – Structures Internal to the Cell Wall
1. Polyisoprenoid branched-chain lipids, are present in which of the following?
a) Archaebacteria
b) Eubacteria
c) Archaebacteria and Eubacteria
d) Cannot be determined
View Answer
a) Archaebacteria
b) Eubacteria
c) Archaebacteria and Eubacteria
d) Cannot be determined
View Answer
Answer: a
Explanation: In Archaebacteria,the lipids are polyisoprenoid branched-chain lipids, in which long-chain branched alcohols(phytanols) are ether linked to glycerol.In Eubacteria,the phospholipids are phosphoglycerides, in which straight-chain fatty acids are ester-linked to glycerol.
Explanation: In Archaebacteria,the lipids are polyisoprenoid branched-chain lipids, in which long-chain branched alcohols(phytanols) are ether linked to glycerol.In Eubacteria,the phospholipids are phosphoglycerides, in which straight-chain fatty acids are ester-linked to glycerol.
Microbiology Questions and Answers – Morphology and Fine Bacteria – Structures Internal to the Cell Wall
This set of Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Morphology and Fine Bacteria – Structures Internal to the Cell Wall”.
1. Polyisoprenoid branched-chain lipids, are present in which of the following?
a) Archaebacteria
b) Eubacteria
c) Archaebacteria and Eubacteria
d) Cannot be determined
View Answer
a) Archaebacteria
b) Eubacteria
c) Archaebacteria and Eubacteria
d) Cannot be determined
View Answer
Answer: a
Explanation: In Archaebacteria,the lipids are polyisoprenoid branched-chain lipids, in which long-chain branched alcohols(phytanols) are ether linked to glycerol.In Eubacteria,the phospholipids are phosphoglycerides, in which straight-chain fatty acids are ester-linked to glycerol.
Explanation: In Archaebacteria,the lipids are polyisoprenoid branched-chain lipids, in which long-chain branched alcohols(phytanols) are ether linked to glycerol.In Eubacteria,the phospholipids are phosphoglycerides, in which straight-chain fatty acids are ester-linked to glycerol.
2. Cytoplasmic membrane and the cell material bounded by it plus the outer membrane of cell is known as _________
a) Protoplast
b) Cytoplast
c) Spheroplast
d) Cell membrane
View Answer
a) Protoplast
b) Cytoplast
c) Spheroplast
d) Cell membrane
View Answer
Answer: c
Explanation: A protoplast is that portion of a bacterial cell consisting of the cytoplasmic membrane and the cell material bounded by it. When the cell has two membranes, the cytoplasmic membrane of the protoplast plus the outer membrane of the cell wall, the cell is called a spheroplast rather than protoplast.
Explanation: A protoplast is that portion of a bacterial cell consisting of the cytoplasmic membrane and the cell material bounded by it. When the cell has two membranes, the cytoplasmic membrane of the protoplast plus the outer membrane of the cell wall, the cell is called a spheroplast rather than protoplast.
3. Which among the following is associated with export of exocellular enzymes?
a) central mesosomes
b) peripheral mesosomes
c) thylakoids
d) nucleus
View Answer
a) central mesosomes
b) peripheral mesosomes
c) thylakoids
d) nucleus
View Answer
Answer: b
Explanation: Peripheral mesosomes show only a shallow penetration into the cytoplasm, are not restricted to a central location, and are not associated with nuclear material and they are involved in export of exocellular enzymes such as penicillinase.
Explanation: Peripheral mesosomes show only a shallow penetration into the cytoplasm, are not restricted to a central location, and are not associated with nuclear material and they are involved in export of exocellular enzymes such as penicillinase.
4. Ribosomes of prokaryotes have a sedimentation coefficient of?
a) 90S
b) 80S
c) 50S
d) 70S
View Answer
a) 90S
b) 80S
c) 50S
d) 70S
View Answer
Answer: d
Explanation: Ribosomes of prokaryotes have a sedimentation coefficient of 70S and are composed of two subunits, a 50S and a 30S subunit. But the ribosomes of eukaryotes have a sedimentation coefficient of 80S and are composed of a 60S and a 40S subunit.
Explanation: Ribosomes of prokaryotes have a sedimentation coefficient of 70S and are composed of two subunits, a 50S and a 30S subunit. But the ribosomes of eukaryotes have a sedimentation coefficient of 80S and are composed of a 60S and a 40S subunit.
5.Poly-beta-hydroxybutyrate(PHB) present in aerobic bacteria can serve as?
a) a reserve carbon and energy source
b) a reserve source of phosphate
c) acceptor of oxygen
d) provides buoyancy
View Answer
a) a reserve carbon and energy source
b) a reserve source of phosphate
c) acceptor of oxygen
d) provides buoyancy
View Answer
Answer: a
Explanation: A polymer found in aerobic bacteria, especially under high-carbon,low-nitrogen culture conditions, is a chlorofoam-soluble, lipid like material, poly-beta-hydroxybutyrate(PHB), which can serve as a reserve carbon and energy source.
Explanation: A polymer found in aerobic bacteria, especially under high-carbon,low-nitrogen culture conditions, is a chlorofoam-soluble, lipid like material, poly-beta-hydroxybutyrate(PHB), which can serve as a reserve carbon and energy source.
Microbiology Questions and Answers – Morphology and Fine Bacteria – Structures Internal to the Cell Wall
This set of Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Morphology and Fine Bacteria – Structures Internal to the Cell Wall”.
1. Polyisoprenoid branched-chain lipids, are present in which of the following?
a) Archaebacteria
b) Eubacteria
c) Archaebacteria and Eubacteria
d) Cannot be determined
View Answer
a) Archaebacteria
b) Eubacteria
c) Archaebacteria and Eubacteria
d) Cannot be determined
View Answer
Answer: a
Explanation: In Archaebacteria,the lipids are polyisoprenoid branched-chain lipids, in which long-chain branched alcohols(phytanols) are ether linked to glycerol.In Eubacteria,the phospholipids are phosphoglycerides, in which straight-chain fatty acids are ester-linked to glycerol.
Explanation: In Archaebacteria,the lipids are polyisoprenoid branched-chain lipids, in which long-chain branched alcohols(phytanols) are ether linked to glycerol.In Eubacteria,the phospholipids are phosphoglycerides, in which straight-chain fatty acids are ester-linked to glycerol.
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2. Cytoplasmic membrane and the cell material bounded by it plus the outer membrane of cell is known as _________
a) Protoplast
b) Cytoplast
c) Spheroplast
d) Cell membrane
View Answer
a) Protoplast
b) Cytoplast
c) Spheroplast
d) Cell membrane
View Answer
Answer: c
Explanation: A protoplast is that portion of a bacterial cell consisting of the cytoplasmic membrane and the cell material bounded by it. When the cell has two membranes, the cytoplasmic membrane of the protoplast plus the outer membrane of the cell wall, the cell is called a spheroplast rather than protoplast.
Explanation: A protoplast is that portion of a bacterial cell consisting of the cytoplasmic membrane and the cell material bounded by it. When the cell has two membranes, the cytoplasmic membrane of the protoplast plus the outer membrane of the cell wall, the cell is called a spheroplast rather than protoplast.
3. Which among the following is associated with export of exocellular enzymes?
a) central mesosomes
b) peripheral mesosomes
c) thylakoids
d) nucleus
View Answer
a) central mesosomes
b) peripheral mesosomes
c) thylakoids
d) nucleus
View Answer
Answer: b
Explanation: Peripheral mesosomes show only a shallow penetration into the cytoplasm, are not restricted to a central location, and are not associated with nuclear material and they are involved in export of exocellular enzymes such as penicillinase.
Explanation: Peripheral mesosomes show only a shallow penetration into the cytoplasm, are not restricted to a central location, and are not associated with nuclear material and they are involved in export of exocellular enzymes such as penicillinase.
4. Ribosomes of prokaryotes have a sedimentation coefficient of?
a) 90S
b) 80S
c) 50S
d) 70S
View Answer
a) 90S
b) 80S
c) 50S
d) 70S
View Answer
Answer: d
Explanation: Ribosomes of prokaryotes have a sedimentation coefficient of 70S and are composed of two subunits, a 50S and a 30S subunit. But the ribosomes of eukaryotes have a sedimentation coefficient of 80S and are composed of a 60S and a 40S subunit.
Explanation: Ribosomes of prokaryotes have a sedimentation coefficient of 70S and are composed of two subunits, a 50S and a 30S subunit. But the ribosomes of eukaryotes have a sedimentation coefficient of 80S and are composed of a 60S and a 40S subunit.
5.Poly-beta-hydroxybutyrate(PHB) present in aerobic bacteria can serve as?
a) a reserve carbon and energy source
b) a reserve source of phosphate
c) acceptor of oxygen
d) provides buoyancy
View Answer
a) a reserve carbon and energy source
b) a reserve source of phosphate
c) acceptor of oxygen
d) provides buoyancy
View Answer
Answer: a
Explanation: A polymer found in aerobic bacteria, especially under high-carbon,low-nitrogen culture conditions, is a chlorofoam-soluble, lipid like material, poly-beta-hydroxybutyrate(PHB), which can serve as a reserve carbon and energy source.
Explanation: A polymer found in aerobic bacteria, especially under high-carbon,low-nitrogen culture conditions, is a chlorofoam-soluble, lipid like material, poly-beta-hydroxybutyrate(PHB), which can serve as a reserve carbon and energy source.
6. Which among the following compound when added to cytoplasmic membrane helps in maintaining the rigidity of cell?
a) lipopolysaccharide
b) hopanoid
c) phosphoglycerides
d) amino acids
View Answer
a) lipopolysaccharide
b) hopanoid
c) phosphoglycerides
d) amino acids
View Answer
Answer: b
Explanation: Hopanoids are hydrophobic chemical compounds which when added to cytoplasmic membrane forms a stable and hard compound that helps in maintaining the rigidity of cell.
Explanation: Hopanoids are hydrophobic chemical compounds which when added to cytoplasmic membrane forms a stable and hard compound that helps in maintaining the rigidity of cell.
7. The nucleoid can be made visible under the light microscope by _________
a) Methylene blue
b) Iodine
c) Nile blue
d) Feulgen staining
View Answer
a) Methylene blue
b) Iodine
c) Nile blue
d) Feulgen staining
View Answer
Answer: d
Explanation: Bacteria consist of nucleotide, consisting of a single, circular DNA molecule in which all the genes are linked and it is not a discrete nucleus. The nucleoid can be made visible under the light microscope by Feulgen staining,which is specific for DNA.
Explanation: Bacteria consist of nucleotide, consisting of a single, circular DNA molecule in which all the genes are linked and it is not a discrete nucleus. The nucleoid can be made visible under the light microscope by Feulgen staining,which is specific for DNA.
8. What helps in the heat resistance of endospore?
a) calcium-DPA complex
b) water
c) methylene
d) calcium
View Answer
a) calcium-DPA complex
b) water
c) methylene
d) calcium
View Answer
Answer: a
Explanation: All endospores contain large amounts of dipicolinic acid (DPA). It occurs in combination with large amounts of calcium and is probably located in the central part of the spore.The calcium-DPA complex play a role in the heat resistance of endospores.
Explanation: All endospores contain large amounts of dipicolinic acid (DPA). It occurs in combination with large amounts of calcium and is probably located in the central part of the spore.The calcium-DPA complex play a role in the heat resistance of endospores.
9. Cysts also have high heat resistance like endospores.
a) True
b) False
View Answer
a) True
b) False
View Answer
Answer: b
Explanation: Cysts are dormant, thick-walled, desiccation-resistant forms that develop by differentiation of a vegetative cell and which can later germinate under suitable conditions. In some ways cysts resemble endospores but they do not have the high heat resistance of endospores.
Explanation: Cysts are dormant, thick-walled, desiccation-resistant forms that develop by differentiation of a vegetative cell and which can later germinate under suitable conditions. In some ways cysts resemble endospores but they do not have the high heat resistance of endospores.
10. Which of the following methods can be utilized for removing peripheral proteins of the cytoplasmic membrane?
a) treatment by detergents
b) osmotic shock
c) heat application
d) destruction of the membrane
View Answer
a) treatment by detergents
b) osmotic shock
c) heat application
d) destruction of the membrane
View Answer
Answer: b
Explanation: Peripheral proteins are loosely attached to cytoplasmic membrane and can be removed by mild treatments such as osmotic shock. On the other hand, integral proteins can be removed only by destruction of the membrane, as with treatment by detergents.
Explanation: Peripheral proteins are loosely attached to cytoplasmic membrane and can be removed by mild treatments such as osmotic shock. On the other hand, integral proteins can be removed only by destruction of the membrane, as with treatment by detergents.
11. Which of the following are true for cytoplasmic membrane?
a) hydrophilic barrier
b) hydrophobic barrier
c) site of generation of protonmotive force
d) hydrophobic barrier and site of generation of protonmotive force
View Answer
a) hydrophilic barrier
b) hydrophobic barrier
c) site of generation of protonmotive force
d) hydrophobic barrier and site of generation of protonmotive force
View Answer
Answer: d
Explanation:The cytoplasmic membrane is a hydrophobic barrier to penetration by most water-soluble molecules. Because of its impermeability to protons, the cytoplasmic membrane is the site of generation of the proton motive force.
Explanation:The cytoplasmic membrane is a hydrophobic barrier to penetration by most water-soluble molecules. Because of its impermeability to protons, the cytoplasmic membrane is the site of generation of the proton motive force.
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