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Papers covered; May 2010

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Microorganisms MCQ's 2010

Microorganisms MCQ's 2010

Pregunta 1 de 25

1

A microbe growing in a functioning refrigerator is probably a:

Selecciona una de las siguientes respuestas posibles:

  • Psychrophile

  • Mesophile

  • Thermophile

  • Hyperthermophile

Explicación

Pregunta 2 de 25

1

Active transport in 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 3 de 25

1

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

Selecciona una de las siguientes respuestas posibles:

  • 5S

  • 16S

  • 18S

  • 23S

Explicación

Pregunta 4 de 25

1

Siderophores:

Selecciona una de las siguientes respuestas posibles:

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

  • Are a key component of cytochromes

  • Help maintain osmotic balance in seawater microbes

  • Develop when errors in membrane synthesis occur

Explicación

Pregunta 5 de 25

1

Chemical energy is released when organic or inorganic compounds are:

Selecciona una de las siguientes respuestas posibles:

  • Reduced

  • Incorporated into larger molecules

  • Synthesized

  • Oxidized

Explicación

Pregunta 6 de 25

1

MacConkey agar selects for:

Selecciona una de las siguientes respuestas posibles:

  • Gram-negative bacteria

  • Gram-positive bacteria

  • Both Gram-positive and Gram-negative bacteria

  • Haemolytic microorganisms

Explicación

Pregunta 7 de 25

1

The bacterial genome is:

Selecciona una de las siguientes respuestas posibles:

  • Mostly diploid but includes several haploid regions

  • A single circular DNA molecule

  • Mostly haploid

  • A double stranded RNA molecule

Explicación

Pregunta 8 de 25

1

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

Selecciona una de las siguientes respuestas posibles:

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

  • Plasmids are a part of bacterial chromosome

  • Plasmids are single stranded DNA found in some bacteria

  • Plasmids are extra chromosomal DNA molecules

Explicación

Pregunta 9 de 25

1

The genomes of positive-sense RNA viruses:

Selecciona una de las siguientes respuestas posibles:

  • Can give rise to infectious virus if transfected into their host tissue culture cells

  • Are fully or partially translated immediately following uncoating in host cells

  • Need to be transcribed to produce mRNA molecules immediately after uncoating

  • Always carry a polymerase molecule in their mature capsid that functions after infection

Explicación

Pregunta 10 de 25

1

The poliovirus mature virus particle:

Selecciona una de las siguientes respuestas posibles:

  • Contains 240 copies of a single protein

  • Contains 60 copies of four proteins

  • Has a dsDNA genome

  • Has a single stranded negative–sense genome

Explicación

Pregunta 11 de 25

1

Which of the following organisms is NOT a true fungus (i.e. it is classified in the Kingdom Protoctista):

Selecciona una de las siguientes respuestas posibles:

  • Phytophthora infestans

  • Botrytis cinerea

  • Agaricus bisporus

  • Taphrina deformans

Explicación

Pregunta 12 de 25

1

Black sigatoka is a:

Selecciona una de las siguientes respuestas posibles:

  • Fungal root disease of bananas

  • Fungal foliar disease of bananas

  • Fungal fruit disease of apples

  • Fungal foliar disease of potatoes

Explicación

Pregunta 13 de 25

1

Which of the following is transmitted to humans by arthropods?

Selecciona una de las siguientes respuestas posibles:

  • Tuberculosis

  • Malaria

  • Cholera

  • Typhoid

Explicación

Pregunta 14 de 25

1

Which of the following is a host component important in specific immune recognition of extracellular microbes?

Selecciona una de las siguientes respuestas posibles:

  • Antigen

  • Antibody

  • Phagocyte

  • Lipopolysaccharide

Explicación

Pregunta 15 de 25

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 usually larger than eukaryote cells

  • Bacteria do not contain a chromosome

  • Bacterial cells are not sensitive to β-lactam antibiotics

Explicación

Pregunta 16 de 25

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 a human alone indicates that it causes disease

  • Determination in a series 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

Explicación

Pregunta 17 de 25

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 all bacterial cells

Explicación

Pregunta 18 de 25

1

A culture of E. coli is diluted by a factor of 10-6 and, after plating out 100 μl on an agar plate, 63 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:

  • 6.3 x 10(7)

  • 6.3 x 10(8)

  • 6.3 x 10(6)

  • 6.3 x 10(5)

Explicación

Pregunta 19 de 25

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

  • Only some Archaea are capable of methanogenesis

  • Archaea are sensitive to β-lactam antibiotics

  • Bacteria have similar RNA polymerase to that of Archaea

Explicación

Pregunta 20 de 25

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 25

1

Fungi primarily contribute to soil and plant health by:

Selecciona una de las siguientes respuestas posibles:

  • Degrading sand particles to release Si

  • Facilitating desiccation of water-logged soils

  • Degrading organic matter and releasing nutrients

  • Preventing bacterial growth

Explicación

Pregunta 22 de 25

1

Fungi tend to live at interfaces. Which of these statements is untrue:

Selecciona una de las siguientes respuestas posibles:

  • This can be where nutrients are most concentrated

  • Solid surfaces may provide anchorage

  • Other microbes, that leak useful metabolites, may inhabit such niches

  • There is typically less water on physical surfaces and fungi avoid water

Explicación

Pregunta 23 de 25

1

Fungal growth and cell division is not normally accompanied by:

Selecciona una de las siguientes respuestas posibles:

  • Biomass aquisition

  • Reduced vitality

  • Nucleic acid replication

  • Enhanced ability to compete with other microbial species

Explicación

Pregunta 24 de 25

1

One factor that is not used to prevent or reduce fungal spoilage of processed foods is:

Selecciona una de las siguientes respuestas posibles:

  • Addition of benzene

  • Low water-activity

  • Refrigeration

  • Heat-sterilization

Explicación

Pregunta 25 de 25

1

Saprophytic activity is essential for biosphere health because it:

Selecciona una de las siguientes respuestas posibles:

  • Facilitates nutrient cycling and waste degradation

  • Kills host organisms and thereby averts overpopulation

  • Facilitates species evolution via endosymbiosis

  • Involves mineralization of inorganic rocks in the lithosphere

Explicación

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