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Papers covered; August 2013 May 2013

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Microorganisms MCQ's 2013 Answered

Questão 1 de 40

1

The cardinal temperatures are the:

Selecione uma das seguintes:

  • Minimum temperatures

  • Optimum temperatures

  • Maximum temperatures

  • Minimum, optimum, and maximum temperatures taken together.

Explicação

Questão 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?

Selecione uma das seguintes:

  • 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

Explicação

Questão 3 de 40

1

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

Selecione uma das seguintes:

  • extreme halophiles

  • extreme thermophiles.

  • methanogens

  • nitrogen-fixing bacteria that live in root nodules

Explicação

Questão 4 de 40

1

Photoautotophs use:

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • Selective medium

  • Differential medium

  • Complex medium

  • Synthetic medium

Explicação

Questão 6 de 40

1

Almost all medically important microbes are:

Selecione uma das seguintes:

  • Chemolithoautotrophs

  • Photoorganoheterotrophs

  • Photolithoautotrophs

  • Chemoorganoheterotrophs

Explicação

Questão 7 de 40

1

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

Selecione uma das seguintes:

  • 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

Explicação

Questão 8 de 40

1

Bacterial Genomics is:

Selecione uma das seguintes:

  • 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

Explicação

Questão 9 de 40

1

All viruses:

Selecione uma das seguintes:

  • 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

Explicação

Questão 10 de 40

1

Underline the TRUE statement below:

Selecione uma das seguintes:

  • Viruses do not infect microorganisms

  • All viruses are enveloped

  • All viruses cause disease

  • All viruses are parasites

Explicação

Questão 11 de 40

1

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

Selecione uma das seguintes:

  • Soil

  • Animals

  • Plants

  • Humans

Explicação

Questão 12 de 40

1

Phytophthora ramorum is the causal pathogen of:

Selecione uma das seguintes:

  • Potato blight

  • Sudden Oak Death

  • Coffee rust

  • Ash dieback

Explicação

Questão 13 de 40

1

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

Selecione uma das seguintes:

  • Heat-killed Mycobacterium tuberculosis

  • Attenuated live Mycobacterium tuberculosis

  • Mycobacterium bovis

  • Attenuated live Mycobacterium bovis

Explicação

Questão 14 de 40

1

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

Selecione uma das seguintes:

  • Malaria

  • Typhoid

  • Plague

  • Meningitis

Explicação

Questão 15 de 40

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 16 de 40

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 17 de 40

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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?

Selecione uma das seguintes:

  • 5.7 x 10(7)

  • 5.7 x 10(8)

  • 5.7 x 10(6)

  • 5.7 x 10(5)

Explicação

Questão 19 de 40

1

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

Selecione uma das seguintes:

  • 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

Explicação

Questão 20 de 40

1

Which statement is CORRECT with respect to peptidoglycan?

Selecione uma das seguintes:

  • 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.

Explicação

Questão 21 de 40

1

Which of the following is a macronutrient?

Selecione uma das seguintes:

  • Manganese

  • Magnesium

  • Zinc

  • Cobalt

Explicação

Questão 22 de 40

1

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

Selecione uma das seguintes:

  • Superoxide anion

  • Hydrogen peroxide

  • Hydroxyl radical

  • All of the above

Explicação

Questão 23 de 40

1

Carrier mediated transport is necessary when:

Selecione uma das seguintes:

  • 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

Explicação

Questão 24 de 40

1

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

Selecione uma das seguintes:

  • 5S

  • 16S

  • 18S

  • 23S

Explicação

Questão 25 de 40

1

Which of these environmental factors influences microbial growth?

Selecione uma das seguintes:

  • pH

  • Water potential

  • Oxygen

  • All of the above

Explicação

Questão 26 de 40

1

The signature sequence is used extensively in the:

Selecione uma das seguintes:

  • Phylogenetic probe

  • Reclassification of misclassified organisms

  • Defining of a specific group within a domain

  • All of the above

Explicação

Questão 27 de 40

1

A Wild-type strain is:

Selecione uma das seguintes:

  • 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

Explicação

Questão 28 de 40

1

Bacterial genes:

Selecione uma das seguintes:

  • Are stretches of double stranded RNA

  • Have introns

  • Are often organised into operons

  • Are always present in two copies

Explicação

Questão 29 de 40

1

Viruses may encode their genomes as:

Selecione uma das seguintes:

  • DNA

  • RNA

  • Negative strand RNA

  • All of the above

Explicação

Questão 30 de 40

1

Poliovirus:

Selecione uma das seguintes:

  • 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

Explicação

Questão 31 de 40

1

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

Selecione uma das seguintes:

  • They are obligate pathogens

  • They are host specific pathogens

  • They have an active saprophytic phase

  • They form basidiospores as part of their life cycle

Explicação

Questão 32 de 40

1

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

Selecione uma das seguintes:

  • Susceptible host

  • Climate change

  • Active pathogen

  • Suitable environment

Explicação

Questão 33 de 40

1

Which of the following is primarily a respiratory pathogen?

Selecione uma das seguintes:

  • Vibrio cholera

  • Mycobacterium tuberculosis

  • Salmonella typhi

  • Mycobacterium leprae

Explicação

Questão 34 de 40

1

Modification of RNA polymerase confers bacterial resistance to:

Selecione uma das seguintes:

  • Beta-lactam antibiotics

  • Rifampicin

  • Quinolone antibiotics

  • Metronidazole

Explicação

Questão 35 de 40

1

Pasteur is attributed with which one of the following discoveries?

Selecione uma das seguintes:

  • 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

Explicação

Questão 36 de 40

1

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

Selecione uma das seguintes:

  • 20 μm

  • 2 μm

  • 200 nm

  • 20 nm

Explicação

Questão 37 de 40

1

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

Selecione uma das seguintes:

  • 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

Explicação

Questão 38 de 40

1

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

Selecione uma das seguintes:

  • It is negatively supercoiled

  • It is positively supercoiled

  • There are typically several origins of replication

  • It consists of over 50 million base pairs

Explicação

Questão 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?

Selecione uma das seguintes:

  • 5.6 x 10(7)

  • 5.6 x 10(8)

  • 5.6 x 10(6)

  • 5.6 x 10(5)

Explicação

Questão 40 de 40

1

Bacterial flagella bring about cell motion by which mechanism?

Selecione uma das seguintes:

  • 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

Explicação

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