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Papers covered; August 2011 May 2011

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Microorganisms MCQ's 2011

Question 1 of 49

1

Modes of obtaining nutrition, used by at least some bacteria, include all of the following EXCEPT:

Select one of the following:

  • Chemolithoautrophy

  • Photolithoautrophy

  • Chemoheteroautrophy

  • Chemoorganoheterotrophy

Explanation

Question 2 of 49

1

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

Select one of the following:

  • Superoxide anion

  • Hydrogen peroxide

  • Hydroxyl radical

  • All of the above

Explanation

Question 3 of 49

1

Carrier mediated transport is necessary when:

Select one of the following:

  • 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

Explanation

Question 4 of 49

1

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

Select one of the following:

  • 5S

  • 16S

  • 18S

  • 23S

Explanation

Question 5 of 49

1

Which of these environmental factors influence microbial growth?

Select one of the following:

  • pH

  • Water potential

  • Oxygen

  • All of the above

Explanation

Question 6 of 49

1

The signature sequence is used extensively in the:

Select one of the following:

  • Phylogenetic probe

  • Reclassification of misclassified organisms

  • Defining of a specific group within a domain

  • All of the above

Explanation

Question 7 of 49

1

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

Select one of the following:

  • Bacterial genome is triploid

  • Bacterial genome is mostly haploid

  • Bacterial genome is mostly diploid

  • Bacterial genome is haploid

Explanation

Question 8 of 49

1

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

Select one of the following:

  • A plasmid is a regulatory gene

  • A plasmid is a short RNA molecule

  • A plasmid is an extra chromosomal DNA molecule

  • A plasmid is a non coding region found in some bacterial genomes

Explanation

Question 9 of 49

1

All viruses:

Select one of the following:

  • Have a genome that is a single molecule of nucleic acid

  • Are enveloped

  • Encode more proteins in their genomes than those contained in the mature virus particle

  • Have capsids that are icosahedral in shape

Explanation

Question 10 of 49

1

Poliovirus:

Select one of the following:

  • 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

Explanation

Question 11 of 49

1

Which of the following is NOT an alternative name for cutaneous fungal infections of humans:

Select one of the following:

  • Superficial mycoses

  • Dermatophytes

  • Mycetoma

  • Ringworms

Explanation

Question 12 of 49

1

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

Select one of the following:

  • Susceptible host

  • Climate change

  • Active pathogen

  • Suitable environment

Explanation

Question 13 of 49

1

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

Select one of the following:

  • Heat-killed Mycobacterium tuberculosis

  • Attenuated live Mycobacterium tuberculosis

  • Mycobacterium bovis

  • Attenuated live Mycobacterium bovis

Explanation

Question 14 of 49

1

Which of the following is a bacterial infection?

Select one of the following:

  • Whooping cough

  • Polio

  • Acquired immunodeficiency syndrome

  • Malaria

Explanation

Question 15 of 49

1

Pasteur is attributed with which one of the following discoveries?

Select one of the following:

  • 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

Explanation

Question 16 of 49

1

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

Select one of the following:

  • 20 μm

  • 2 μm

  • 200 nm

  • 20 nm

Explanation

Question 17 of 49

1

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

Select one of the following:

  • 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

Explanation

Question 18 of 49

1

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

Select one of the following:

  • It is negatively supercoiled

  • It is positively supercoiled

  • There are typically several origins of replication

  • It consists of over 50 million base pairs

Explanation

Question 19 of 49

1

A culture of E. coli is diluted by a factor of 10-6 and, after plating out 100 μl on an agar plate, 93 colonies grew after incubation at 37oC overnight. The original culture therefore contained how many viable E. coli cells per ml?

Select one of the following:

  • 9.3 x 10(7)

  • 9.3 x 10(8)

  • 9.3 x 10(6)

  • 9.3 x 10(5)

Explanation

Question 20 of 49

1

Bacterial flagella bring about cell motion by which mechanism?

Select one of the following:

  • 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

Explanation

Question 21 of 49

1

In the Earth’s biosphere most fungal biomass and diversity is found:

Select one of the following:

  • In the oceans

  • In soils

  • Under glaciers

  • In the atmosphere

Explanation

Question 22 of 49

1

Fungal growth and cell division is NOT normally accompanied by:

Select one of the following:

  • Biomass acquisition

  • Reduced vitality

  • Nucleic-acid replication

  • Enhanced ability to compete with other microbial species

Explanation

Question 23 of 49

1

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

Select one of the following:

  • Addition of benzene

  • Low water-activity

  • Refrigeration

  • Heat-sterilization

Explanation

Question 24 of 49

1

Saprophytic activity is essential for the health of the biosphere because:

Select one of the following:

  • It facilitates nutrient cycling and waste degradation

  • It kills host organisms and thereby averts overpopulation

  • It facilitates species evolution via endosymbiosis

  • It involves mineralization of inorganic rocks in the lithosphere

Explanation

Question 25 of 49

1

The cardinal temperatures are the:

Select one of the following:

  • Minimum temperatures

  • Optimum temperatures

  • Maximum temperatures

  • Minimum, optimum, and maximum temperatures taken together

Explanation

Question 26 of 49

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?

Select one of the following:

  • 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

Explanation

Question 27 of 49

1

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

Select one of the following:

  • Extreme halophiles

  • Extreme thermophiles

  • Methanogens

  • Nitrogen-fixing bacteria that live in root nodules

Explanation

Question 28 of 49

1

Photoautotophs use:

Select one of the following:

  • 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

Explanation

Question 29 of 49

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:

Select one of the following:

  • Selective medium

  • Differential medium

  • Complex medium

  • Synthetic medium

Explanation

Question 30 of 49

1

A microbe growing in a functioning refrigerator is probably a:

Select one of the following:

  • Psychrophile

  • Mesophile

  • Thermophile

  • Hyperthermophile

Explanation

Question 31 of 49

1

Which one of the following sentences correctly describes the science of Metagenomics?

Select one of the following:

  • Metagenomics is a genome- level study of the whole microbial community

  • Metagenomics is a genomics of industrially and medically important bacteria

  • Metagenomics is a study of genes’ expression

  • Metagenomics is a comparative analysis of the sequenced microbial genomes

Explanation

Question 32 of 49

1

Genetic recombination is a:

Select one of the following:

  • Change of DNA structure caused by radiation

  • Amplification of DNA molecules followed by cell division

  • Physical exchange between DNA molecules

  • Process resulting in protein synthesis

Explanation

Question 33 of 49

1

All viruses:

Select one of the following:

  • 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

Explanation

Question 34 of 49

1

Tobacco mosaic virus has:

Select one of the following:

  • An icosahedral capsid

  • A helical capsid

  • Multiple copies of each of four proteins making up the capsid

  • Multiple copies of two proteins making up the capsid

Explanation

Question 35 of 49

1

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

Select one of the following:

  • Soil

  • Animals

  • Plants

  • Humans

Explanation

Question 36 of 49

1

Secondary symptoms of infections of plants by pathogens:

Select one of the following:

  • Occur at some distance from the point of infection

  • Normally occur close to the site of active infection

  • Are an ideal place to isolate the causal organism

  • Never occur at the same time as primary symptoms

Explanation

Question 37 of 49

1

Which one of the following infectious diseases has been eradicated from the human population?

Select one of the following:

  • Plague

  • Leprosy

  • Small pox

  • Polio

Explanation

Question 38 of 49

1

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

Select one of the following:

  • Antigen

  • Antibody

  • Phagocyte

  • Lipopolysaccharide

Explanation

Question 39 of 49

1

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

Select one of the following:

  • 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

Explanation

Question 40 of 49

1

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

Select one of the following:

  • 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

Explanation

Question 41 of 49

1

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

Select one of the following:

  • 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

Explanation

Question 42 of 49

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?

Select one of the following:

  • 5.7 x 10(7)

  • 5.7 x 10(8)

  • 5.7 x 10(6)

  • 5.7 x 10(5)

Explanation

Question 43 of 49

1

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

Select one of the following:

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

  • Only some Archaea are capable of methanogenesis

  • Archaea are sensitive to β-lactam antibiotics

  • Bacteria have similar RNA polymerase to that of Archaea

Explanation

Question 44 of 49

1

Which statement is CORRECT with respect to peptidoglycan?

Select one of the following:

  • 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

Explanation

Question 45 of 49

1

The primary reason that health professionals recommend that new-born babies are not washed is:

Select one of the following:

  • So that they can be inoculated with symbiotic yeast species

  • To avoid imbalances in the microbial ecology of indigenous flora

  • To avoid accidental contamination with fungal spores

  • So that clinical microbiologists can study the impact on the current generation

Explanation

Question 46 of 49

1

Post-genomic techniques include:

Select one of the following:

  • Proteomics

  • Use of restriction enzymes

  • Gene sequencing

  • Studies of signal-transduction pathways

Explanation

Question 47 of 49

1

Systems biology approaches to the study of fungal cells do NOT necessarily involve:

Select one of the following:

  • Generation of data from biological experiments

  • Mathematical quantification of changes in cell components

  • Creation of a model of the cellular system in silico

  • Creation of a conceptual model based on philosophical techniques

Explanation

Question 48 of 49

1

Which of these statements is untrue?

Select one of the following:

  • Some species of yeasts are highly tolerant to ethanol stress

  • Some species of fungi are extremely xerophilic

  • Many fungi are more tolerant to water stress than any bacterial species

  • Fungi can grow over the entire pH range from 0 to 14

Explanation

Question 49 of 49

1

An extremophilic microbe is one which:

Select one of the following:

  • Can survive dry conditions

  • Can grow only when there is a mixture of stress parameters (e.g. high temperatures and low pH)

  • Can grow optimally under extreme conditions

  • Becomes dormant under extreme conditions

Explanation

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