All the following about the bacterial capsule is true EXCEPT:
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3%
Usually polysaccharide in nature
0%
Acts to prevent phagocytosis
79%
Plays a role in bacterial division
18%
May show and determine serotypes
Bacterial capsules have the following characters EXCEPT:
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3%
They are important virulence factors
55%
They are lipopolysaccharides in nature
34%
They are formed only inside the host (in vivo)
8%
They protect the cell wall against various kinds of antibacterial agents
Bacteria are protected from phagocytosis by:
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92%
The capsule
0%
The mesosome
1%
The outer membrane
3%
The cell wall
4%
The endospores
The structure which protects bacteria from bacteriophages is:
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3%
The pill
87%
The capsule
8%
The cell wall
3%
The flagella
Which of the following structures may be used for attachment of bacterial cells to surfaces and to other cells?
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15%
Fimbriae
0%
Cell wall
9%
Glycocalyx
6%
Both a and b
69%
Both a and c
Each of the following statements is correct EXCEPT:
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3%
Pili help attachment of bacteria to mucosal epithelium
14%
Both Gram negative bacilli and cocci have lipopolysaccharide (endotoxin) in their cell wall
74%
Bacterial flagella are non-antigenic in humans
9%
The sex pilus is involved in transfer of DNA between bacteria
All of the flowing are true concerning pili EXCEPT:
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3%
They mediate bacterial adherence
9%
They may be involved in bacterial conjugation
70%
Their antigen is called H antigen
17%
They are important virulence factors
Each of the following statements concerning bacterial spores is correct EXCEPT:
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11%
Spores are resistant to boiling
75%
The bacterial chromosome is not included in the spore
5%
Spores are metabolically inactive
10%
The spores coats contain dipicolinic acid
The marked resistance of the spores can be attributed to all the following factors EXCEPT
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5%
The impermeability of their cortex and outer coat
64%
Their ability to resist phagocytosis
10%
Their very low metabolic and enzymatic activity
21%
Their high content of Ca and dipicolinic acid
Which structure is responsible for bacterial motility
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6%
Fimbria
94%
Flagellum
0%
Glycocalyx
0%
Mesosome
Which of the following statements about prokaryotes is TRUE?
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2%
They contain membrane-bound organelles.
8%
Their DNA is enclosed within a nuclear membrane
81%
They contain a 70S ribosome
5%
They have sterols in their cell membrane like eukaryotes
5%
Their DNA is organized into chromosomes
Which of the following is NOT a characteristic of eukaryotic cells?
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3%
Larger and more developed compared to prokaryotic cells
89%
Contains 70S ribosomes
5%
Contains membrane-bound organelles
2%
Has a true nucleus enclosed by a nuclear membrane
2%
Sterols are present in the cell membrane
What is a key difference between prokaryotic and eukaryotic ribosomes?
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0%
Prokaryotic ribosomes are 80S, while eukaryotic ribosomes are 705
3%
Eukaryotic ribosomes are 70S, while prokaryotic ribosomes are 80S
90%
Prokaryotic ribosomes are 705, while eukaryotic ribosomes are 805
5%
Prokaryotic ribosomes are membrane-bound
2%
Both contain 80S ribosomes but in different compartments
Which of the following microorganisms is classified as a eukaryote?
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3%
Bacteria
1%
Mycoplasma
1%
Archaebacteria
89%
Fungi
6%
Viruses
Which of the following microorganisms lacks both DNA and RNA?
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90%
Prions
4%
Viruses
3%
Fungi
0%
Algae
3%
Protozoa
What is the primary role of sterols in eukaryotic cell membranes?
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10%
They provide nutrients to the cell
86%
They maintain the cell's structural integrity
2%
They assist in protein synthesis
2%
They are absent in eukaryotes but present in prokaryotes
2%
They help in DNA replication
Which of the following statements about viruses is INCORRECT?
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3%
They have no cellular structure
1%
They are obligate intracellular parasites
91%
They contain both DNA and RNA simultaneously
1%
They depend on host cells to replicate
3%
They are among the smallest infectious agents
Mycoplasma is unique among bacteria because:
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10%
It lacks sterols in its cell membrane
1%
It has a true nucleus
81%
It contains no cell wall
3%
It has 80S ribosomes like eukaryotes
4%
It has a thicker peptidoglycan layer
Which of the following best describes the DNA organization in prokaryotes?
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3%
DNA is contained in a true nucleus
2%
DNA is linear and associated with histones
71%
DNA is organized as a long folded thread in the nucleoid
23%
DNA is circular and membrane-bound
2%
DNA is found in multiple chromosomes
What is the composition of the bacterial cell wall that gives it strength?
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14%
Sterols
1%
Lipopolysaccharide
80%
Peptidoglycan
1%
Protein subunits
4%
Phospholipids