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Papers covered; August 2013 May 2013

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Microorganisms MCQ's 2013 Answered

Pregunta 1 de 40

1

The cardinal temperatures are the:

Selecciona una de las siguientes respuestas posibles:

  • Minimum temperatures

  • Optimum temperatures

  • Maximum temperatures

  • Minimum, optimum, and maximum temperatures taken together.

Explicación

Pregunta 2 de 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?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 3 de 40

1

Which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?

Selecciona una de las siguientes respuestas posibles:

  • extreme halophiles

  • extreme thermophiles.

  • methanogens

  • nitrogen-fixing bacteria that live in root nodules

Explicación

Pregunta 4 de 40

1

Photoautotophs use:

Selecciona una de las siguientes respuestas posibles:

  • Light as an energy source and CO2 as a carbon source

  • Light as an energy and methane as a carbon source

  • CO2 as both an energy source and a carbon source

  • All of the above.

Explicación

Pregunta 5 de 40

1

Addition of blood to a culture medium only allows the haemolytic bacteria that grow on the plate to be picked out. This is an example of a:

Selecciona una de las siguientes respuestas posibles:

  • Selective medium

  • Differential medium

  • Complex medium

  • Synthetic medium

Explicación

Pregunta 6 de 40

1

Almost all medically important microbes are:

Selecciona una de las siguientes respuestas posibles:

  • Chemolithoautotrophs

  • Photoorganoheterotrophs

  • Photolithoautotrophs

  • Chemoorganoheterotrophs

Explicación

Pregunta 7 de 40

1

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

Selecciona una de las siguientes respuestas posibles:

  • A plasmid is extra chromosomal DNA that encodes only resistance to antibiotics

  • A plasmid is a part of the bacterial chromosome

  • A plasmid is single stranded DNA found in some bacteria

  • A plasmid is an extra chromosomal DNA molecule

Explicación

Pregunta 8 de 40

1

Bacterial Genomics is:

Selecciona una de las siguientes respuestas posibles:

  • A study of the entire bacterial genome

  • Sequencing of the bacterial chromosome

  • A study of essential genes and genetic elements

  • Sequencing of DNA samples obtained from the environment

Explicación

Pregunta 9 de 40

1

All viruses:

Selecciona una de las siguientes respuestas posibles:

  • Enter cells by receptor-mediated endocytosis

  • Replicate their genomes in the nucleus of the cell

  • Replicate their genomes in the cytoplasm of the cell

  • Surround their progeny genomes with capsid proteins inside infected cells

Explicación

Pregunta 10 de 40

1

Underline the TRUE statement below:

Selecciona una de las siguientes respuestas posibles:

  • Viruses do not infect microorganisms

  • All viruses are enveloped

  • All viruses cause disease

  • All viruses are parasites

Explicación

Pregunta 11 de 40

1

Anthrophilic dermatophytes (fungi causing cutaneous infections of humans) are primarily associated with:

Selecciona una de las siguientes respuestas posibles:

  • Soil

  • Animals

  • Plants

  • Humans

Explicación

Pregunta 12 de 40

1

Phytophthora ramorum is the causal pathogen of:

Selecciona una de las siguientes respuestas posibles:

  • Potato blight

  • Sudden Oak Death

  • Coffee rust

  • Ash dieback

Explicación

Pregunta 13 de 40

1

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

Selecciona una de las siguientes respuestas posibles:

  • Heat-killed Mycobacterium tuberculosis

  • Attenuated live Mycobacterium tuberculosis

  • Mycobacterium bovis

  • Attenuated live Mycobacterium bovis

Explicación

Pregunta 14 de 40

1

Which of the following is transmitted via the faecal-oral-route?

Selecciona una de las siguientes respuestas posibles:

  • Malaria

  • Typhoid

  • Plague

  • Meningitis

Explicación

Pregunta 15 de 40

1

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

Selecciona una de las siguientes respuestas posibles:

  • Bacterial cells do not contain mitochondria.

  • Bacterial cells are always larger than eukaryote cells.

  • Bacteria do not contain a chromosome.

  • Eukaryotic cells are sensitive to β-lactam antibiotics.

Explicación

Pregunta 16 de 40

1

Koch’s postulates MOST CORRECTLY relate to which one of the following statements?

Selecciona una de las siguientes respuestas posibles:

  • The isolation of a bacterium in culture from an infection alone indicates that it caused the disease.

  • Isolation and cultivation of a microorganism from a diseased animal, then inoculation into another healthy animal to cause the same disease followed by re-isolation of the same microorganism indicates that it is the cause of the disease.

  • The observation of virus particles in tissue from a human with disease indicates that it has caused the disease.

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

Explicación

Pregunta 17 de 40

1

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

Selecciona una de las siguientes respuestas posibles:

  • 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 associated with found inside all bacterial cells.

Explicación

Pregunta 18 de 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, 57 colonies grew after incubation at 37oC overnight. The original culture therefore contained how many viable E. coli cells per ml?

Selecciona una de las siguientes respuestas posibles:

  • 5.7 x 10(7)

  • 5.7 x 10(8)

  • 5.7 x 10(6)

  • 5.7 x 10(5)

Explicación

Pregunta 19 de 40

1

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

Selecciona una de las siguientes respuestas posibles:

  • Both have peptidoglycan in their cell walls

  • No bacteria and only some Archaea are capable of methanogenesis

  • Archaea and bacteria are sensitive to β-lactam antibiotics

  • Bacteria have similar RNA polymerase to that of Archaea

Explicación

Pregunta 20 de 40

1

Which statement is CORRECT with respect to peptidoglycan?

Selecciona una de las siguientes respuestas posibles:

  • 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 Gram negative cell walls.

Explicación

Pregunta 21 de 40

1

Which of the following is a macronutrient?

Selecciona una de las siguientes respuestas posibles:

  • Manganese

  • Magnesium

  • Zinc

  • Cobalt

Explicación

Pregunta 22 de 40

1

Which of the following forms of oxygen are generally toxic to living organisms?

Selecciona una de las siguientes respuestas posibles:

  • Superoxide anion

  • Hydrogen peroxide

  • Hydroxyl radical

  • All of the above

Explicación

Pregunta 23 de 40

1

Carrier mediated transport is necessary when:

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 24 de 40

1

The size (as determined by the sedimentation factor) of the most useful RNA molecule for prokaryotic evolutionary studies is:

Selecciona una de las siguientes respuestas posibles:

  • 5S

  • 16S

  • 18S

  • 23S

Explicación

Pregunta 25 de 40

1

Which of these environmental factors influences microbial growth?

Selecciona una de las siguientes respuestas posibles:

  • pH

  • Water potential

  • Oxygen

  • All of the above

Explicación

Pregunta 26 de 40

1

The signature sequence is used extensively in the:

Selecciona una de las siguientes respuestas posibles:

  • Phylogenetic probe

  • Reclassification of misclassified organisms

  • Defining of a specific group within a domain

  • All of the above

Explicación

Pregunta 27 de 40

1

A Wild-type strain is:

Selecciona una de las siguientes respuestas posibles:

  • A bacterial or viral strain with minimum of mutations in its genome

  • An arbitrarily chosen strain; other strains compared with it

  • A strain adapted to laboratory conditions

  • A strain that dominates the natural environment

Explicación

Pregunta 28 de 40

1

Bacterial genes:

Selecciona una de las siguientes respuestas posibles:

  • Are stretches of double stranded RNA

  • Have introns

  • Are often organised into operons

  • Are always present in two copies

Explicación

Pregunta 29 de 40

1

Viruses may encode their genomes as:

Selecciona una de las siguientes respuestas posibles:

  • DNA

  • RNA

  • Negative strand RNA

  • All of the above

Explicación

Pregunta 30 de 40

1

Poliovirus:

Selecciona una de las siguientes respuestas posibles:

  • Has a double-stranded DNA genome

  • Has a capsid that is composed of 240 copies of a single protein

  • Replicates primarily in the upper respiratory tract

  • Belongs to the enterovirus genus of the picornavirus family

Explicación

Pregunta 31 de 40

1

Which of the following statements is NOT true about rust fungi?

Selecciona una de las siguientes respuestas posibles:

  • They are obligate pathogens

  • They are host specific pathogens

  • They have an active saprophytic phase

  • They form basidiospores as part of their life cycle

Explicación

Pregunta 32 de 40

1

Which of the following is NOT part of the plant disease triangle:

Selecciona una de las siguientes respuestas posibles:

  • Susceptible host

  • Climate change

  • Active pathogen

  • Suitable environment

Explicación

Pregunta 33 de 40

1

Which of the following is primarily a respiratory pathogen?

Selecciona una de las siguientes respuestas posibles:

  • Vibrio cholera

  • Mycobacterium tuberculosis

  • Salmonella typhi

  • Mycobacterium leprae

Explicación

Pregunta 34 de 40

1

Modification of RNA polymerase confers bacterial resistance to:

Selecciona una de las siguientes respuestas posibles:

  • Beta-lactam antibiotics

  • Rifampicin

  • Quinolone antibiotics

  • Metronidazole

Explicación

Pregunta 35 de 40

1

Pasteur is attributed with which one of the following discoveries?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

Pregunta 36 de 40

1

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

Selecciona una de las siguientes respuestas posibles:

  • 20 μm

  • 2 μm

  • 200 nm

  • 20 nm

Explicación

Pregunta 37 de 40

1

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

Selecciona una de las siguientes respuestas posibles:

  • Both have peptidoglycan in their cell walls

  • No bacteria and only some Archaea are capable of methanogenesis

  • Archaea and bacteria are sensitive to β-lactam antibiotics

  • Bacteria have similar RNA polymerase to that of Archaea

Explicación

Pregunta 38 de 40

1

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

Selecciona una de las siguientes respuestas posibles:

  • It is negatively supercoiled

  • It is positively supercoiled

  • There are typically several origins of replication

  • It consists of over 50 million base pairs

Explicación

Pregunta 39 de 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, 56 colonies grew after incubation at 37oC overnight. The original culture therefore contained how many viable E. coli cells per ml?

Selecciona una de las siguientes respuestas posibles:

  • 5.6 x 10(7)

  • 5.6 x 10(8)

  • 5.6 x 10(6)

  • 5.6 x 10(5)

Explicación

Pregunta 40 de 40

1

Bacterial flagella bring about cell motion by which mechanism?

Selecciona una de las siguientes respuestas posibles:

  • 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

Explicación

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