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Microorganisms MCQ's 2012

Microorganisms MCQ's 2012

Frage 1 von 40

1

Which of the following is a macronutrient?

Wähle eine der folgenden:

  • Manganese

  • Magnesium

  • Zinc

  • Cobalt

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Frage 2 von 40

1

Denitrification is a process by which:

Wähle eine der folgenden:

  • Nitrogen gas is fixed by microorganisms

  • Nitrates are reduced to nitrogen gas

  • Nitrates are reduced to ammonia

  • Nitrogen is assimilated into cellular material

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Frage 3 von 40

1

Carl Woese of the University of Illinois and his collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains?

Wähle eine der folgenden:

  • Microscopic examination of the staining characteristics of the cell wall

  • Metabolic characteristics such as the production of methane gas

  • Ecological characteristics such as the ability to survive extreme temperatures

  • Molecular characteristics such as ribosomal RNA sequences

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Frage 4 von 40

1

Catalase is indispensable to:

Wähle eine der folgenden:

  • Obligate anaerobes

  • Aerotolerant anaerobes

  • Aerobes

  • All of the above

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Frage 5 von 40

1

Addition of blood to a culture medium allows haemolytic bacteria to be picked out. This is an example of a:

Wähle eine der folgenden:

  • Selective medium

  • Differential medium

  • Synthetic medium

  • Defined medium

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Frage 6 von 40

1

Which of these environmental factors influence microbial growth?

Wähle eine der folgenden:

  • pH

  • Water potential

  • Oxygen

  • All of the above

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Frage 7 von 40

1

Mutations are:

Wähle eine der folgenden:

  • Chemical modifications of DNA or RNA molecules

  • Any changes of bacterial genome as compared with a wild type

  • Events resulting from genetic exchange between bacterial plasmids

  • Sequencing errors

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Frage 8 von 40

1

A Wild-type bacterial strain is:

Wähle eine der folgenden:

  • A strain with a limited number of mutations

  • An arbitrarily chosen strain

  • A strain without plasmids

  • A strain which is sensitive to antibiotics

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Frage 9 von 40

1

Viruses may encode their genomes as:

Wähle eine der folgenden:

  • DNA

  • RNA

  • negative strand RNA

  • All of the above

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Frage 10 von 40

1

Virus particles:

Wähle eine der folgenden:

  • Are always smaller than bacterial cells

  • Can replicate independently of a host cell if provided with a nutrient medium

  • Can use some of the enzymes expressed in the host cell to aid their replication

  • Are always eliminated by the host immune system

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Frage 11 von 40

1

The symptom ‘chlorosis’ which develops when some fungi infect plants is due to:

Wähle eine der folgenden:

  • Cell death

  • Nutrient imbalance

  • Impaired photosynthesis

  • Excess plant hormones

Erklärung

Frage 12 von 40

1

Which of the following is NOT a correct statement about true fungi:

Wähle eine der folgenden:

  • True fungi are eukaryotic

  • All true fungi are multi-cellular

  • True fungi are heterotrophic

  • Most true fungi have chitin cell walls

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Frage 13 von 40

1

The Bacille-Calmette-Guérin (BCG) vaccine is:

Wähle eine der folgenden:

  • Heat-killed Mycobacterium tuberculosis

  • Attenuated live Mycobacterium tuberculosis

  • Mycobacterium bovis

  • Attenuated live Mycobacterium bovis

Erklärung

Frage 14 von 40

1

Which of the following is transmitted to humans by arthropods?

Wähle eine der folgenden:

  • Tuberculosis

  • Malaria

  • Cholera

  • Typhoid

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Frage 15 von 40

1

Pasteur is attributed with which one of the following discoveries?

Wähle eine der folgenden:

  • Was the first to see microorganisms under a microscope

  • First to discover and use agar

  • That there could be life without air

  • The first chemical antibiotics

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Frage 16 von 40

1

The length of a typical E. coli cell is approximately?

Wähle eine der folgenden:

  • 20 μm

  • 2 μm

  • 200 nm

  • 20 nm

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Frage 17 von 40

1

With respect to differences between members of the archaeal and bacterial domains/kingdoms, which is the CORRECT statement?

Wähle eine der folgenden:

  • Both have peptidoglycan in their cell walls

  • Only some Archaea are capable of methanogenesis

  • Archaea are sensitive to β-lactam antibiotics

  • Bacteria have similar RNA polymerase to that of Archaea

Erklärung

Frage 18 von 40

1

Which statement is correct with respect to the E. coli chromosome?

Wähle eine der folgenden:

  • It is negatively supercoiled

  • It is positively supercoiled

  • There are typically several origins of replication

  • It consists of over 50 million base pairs

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Frage 19 von 40

1

A culture of E. coli is diluted by a factor of x 10-5 and, after plating out 100 μl on an agar plate, 78 colonies grew after incubation at 37oC overnight. The original culture therefore contained how many viable E. coli cells per ml?

Wähle eine der folgenden:

  • 7.8 x 10(7)

  • 7.8 x 10(8)

  • 7.8 x 10(6)

  • 7.8 x 10(5)

Erklärung

Frage 20 von 40

1

Bacterial flagella bring about cell motion by which mechanism?

Wähle eine der folgenden:

  • Wave-like movement of the flagellum

  • Rotation of the cell

  • Rotation of the flagellum in one direction only

  • Rotation of the flagellum that is reversible

Erklärung

Frage 21 von 40

1

Incorporation of atmospheric N2 to NH4+ occurs via the process of:

Wähle eine der folgenden:

  • Nitrogen fixation

  • Nitrification

  • Denitrification

  • None of the above, atmospheric N2 cannot be incorporated into NH4+.

Erklärung

Frage 22 von 40

1

Active transport is necessary when:

Wähle eine der folgenden:

  • Diffusion will not allow adequate amounts of a substance to enter the cell

  • Movement into the cell is against a concentration gradient

  • The level of nutrients in nature is very low

  • All of the above

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Frage 23 von 40

1

The size of the most useful RNA molecule for prokaryotic evolutionary studies is:

Wähle eine der folgenden:

  • 5S

  • 16S

  • 18S

  • 23S

Erklärung

Frage 24 von 40

1

Siderophores:

Wähle eine der folgenden:

  • Act as a solvent for iron and transport iron into the cells

  • Are a key component of cytochromes

  • Help maintain osmotic balance in seawater microbes

  • Develop when errors in membrane synthesis occur

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Frage 25 von 40

1

Chemical energy is released when organic or inorganic compounds are:

Wähle eine der folgenden:

  • Reduced

  • Incorporated into larger molecules

  • Synthesized

  • Oxidized

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Frage 26 von 40

1

MacConkey agar selects for:

Wähle eine der folgenden:

  • Gram-negative enteric bacteria

  • Gram-positive bacteria

  • Both Gram-positive and Gram-negative bacteria

  • Haemolytic microorganisms

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Frage 27 von 40

1

The Bacterial chromosome is:

Wähle eine der folgenden:

  • Circular DNA

  • Linear DNA

  • Either circular or linear DNA

  • Double stranded RNA

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Frage 28 von 40

1

With regards to bacterial plasmids which statement is the CORRECT one?

Wähle eine der folgenden:

  • Plasmids are extra chromosomal DNA that encode only resistance to antibiotics

  • Plasmids are a part of the bacterial chromosome

  • Plasmids are single stranded DNA found in some bacteria

  • Plasmids are extra chromosomal DNA molecules

Erklärung

Frage 29 von 40

1

Which is the TRUE statement below:

Wähle eine der folgenden:

  • Viruses do not infect microorganisms

  • All viruses are enveloped

  • All viruses cause disease

  • All viruses are parasites

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Frage 30 von 40

1

The poliovirus mature virus particle:

Wähle eine der folgenden:

  • Contains 240 copies of a single protein

  • Contains 60 copies of four proteins

  • Has a dsDNA genome

  • Has a single stranded negative–sense genome

Erklärung

Frage 31 von 40

1

Phytophthora infestans is a fungus-like organism which:

Wähle eine der folgenden:

  • Causes disease of a wide range of woody hosts

  • Causes potato blight

  • Causes ringworm

  • Causes black sigatoka disease of banana

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Frage 32 von 40

1

Zoophilic dermatophytes are:

Wähle eine der folgenden:

  • normally associated with animals and humans

  • normally only associated with humans

  • mainly associated with the soil

  • mainly associated with contaminated water

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Frage 33 von 40

1

Which of the following is primarily a respiratory pathogen?

Wähle eine der folgenden:

  • Vibrio cholerae

  • Mycobacterium tuberculosis

  • Salmonella typhi

  • Mycobacterium leprae

Erklärung

Frage 34 von 40

1

Which of the following is NOT an acquired mechanism of antibiotic resistance in bacteria?

Wähle eine der folgenden:

  • Beta-lactamase production

  • Efflux pump antibiotic export

  • Lack of peptidoglycan

  • RNA polymerase single nucleotide change

Erklärung

Frage 35 von 40

1

With regard to the differences between bacterial and eukaryotic cells which statement is the CORRECT one?

Wähle eine der folgenden:

  • Bacterial cells contain mitochondria

  • Bacterial cells are usually larger than eukaryote cells

  • Bacteria do not contain a chromosome

  • Only bacterial cells are sensitive to β-lactam antibiotics

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Frage 36 von 40

1

Koch’s postulates most correctly relate to which one of the following statements?

Wähle eine der folgenden:

  • The isolation of a bacterium in culture from a human alone indicates that it causes disease

  • Determination in a series of logical steps the agent that causes disease

  • The observation of bacterial cells in tissue from a human with disease indicates that the observed bacterium has caused the disease

  • Inoculation of a bacterium into an animal to cause disease alone indicates that it is the cause of the disease observed

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Frage 37 von 40

1

Which statement is CORRECT with respect to Lipopolysaccharide (LPS)?

Wähle eine der folgenden:

  • LPS is found in Gram positive cells

  • LPS is found in Gram negative cells in the cytoplasmic membrane

  • LPS is found in the outer-membrane of Gram negative cells.

  • LPS is found inside all bacterial cells

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Frage 38 von 40

1

A culture of E. coli is diluted by a factor of 10-6 and, after plating out 100 μl on an agar plate, 94 colonies grew after incubation at 37oC overnight. The original culture therefore contained how many viable E. coli cells per ml?

Wähle eine der folgenden:

  • 9.4 x 10(7)

  • 9.4 x 10(8)

  • 9.4 x 10(6)

  • 9.4 x 10(5)

Erklärung

Frage 39 von 40

1

With respect to differences between members of the archaeal and bacterial domains/kingdoms, which is the CORRECT statement?

Wähle eine der folgenden:

  • Both have peptidoglycan in their cell walls

  • Only some Archaea are capable of methanogenesis

  • Archaea are sensitive to β-lactam antibiotics

  • Bacteria have similar RNA polymerase to that of Archaea

Erklärung

Frage 40 von 40

1

Which statement is CORRECT with respect to peptidoglycan?

Wähle eine der folgenden:

  • There are multiple molecules of peptidoglycan in bacterial cell walls

  • Only Gram positive cells possess peptidoglycan

  • There is only a single molecule of peptidoglycan in a bacterial cell wall

  • Peptidoglycan is only found in the Gram negative cell wall

Erklärung

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