PRACTICE EXAM 2 Flashcards
- Bacteria stain as gram-positive or gram-negative because they differ in their:
(a) Shape
(b) Cytoplasmic membrane
(c) Cell wall
(d) Outer membrane
Cell wall
- Who of the following developed a set of criteria that could be used to establish a causative link between a particular microorganism and a particular disease?
(a) Louis Pasteur
(b) Antoine van Leeuwenhoek
(c) Robert Koch
(e) Edward Jenner
Robert Koch
- What would you expect to see under a microscope if you were to stain Archaeal cells using the Gram staining procedure?
(a) Pink coloured cells
(b) Purple coloured cells
(c) Colourless cells
(d) Nothing
Pink coloured cells
- All viruses have which one of the following characteristics in common?
(a) Lipid outer covering
(b) Obligate intracellular parasites
(c) Contain RNA as their genomic material
(d) Composed of a head and tail with tail fibres
Obligate intracellular parasites
- Archaea were first revealed when:
(a) Molecular sequencing was used as a means of classifying microbes
(b) Advanced sampling techniques enabled hydrothermal vents to be examined
(c) Stromatolites were first sampled
(d) None of the above
Molecular sequencing was used as a means of classifying microbes
- Which of the following is true for all organisms?
(a) They require organic nutrients
(b) They require inorganic nutrients
(c) They require oxygen
(d) None of the above are true
They require inorganic nutrients
- Which of the following is true about the production of lytic bacteriophages?
(a) They are produced straight away
(b) The host decides on the number that are made throughout the infection
(c) The viral genome is integrated into the host chromosome
(d) None of the above
They are produced straight away
- You have isolated an unknown microbe from bottom sediments of a lake. Observations reveal that the microbe will grow between 14C and 41C with a growth optimum of 26C. From this information, the microbe would be classified as:
(a) Psychrophilic
(b) Thermotolerant
(c) Psychrotolerant
(d) Mesophilic
Mesophilic
- A non-halophilic bacterium put into a high salt environment will:
(a) Be hypertonic and plasmolyse
(b) Be hypotonic and burst
(c) Be in an isotonic environment
(d) Not be effected at all
Be hypertonic and plasmolyse
- Microorganisms utilising atmospheric oxygen and also growing in the absence of oxygen are:
(a) Obligate aerobes
(b) Aerotolerant anaerobes
(c) Facultative anaerobes
(d) Obligate anaerobes
Facultative anaerobes
- The metabolic process of Cyanobacteria and Algae is:
(a) Anaerobic respiration
(b) Anoxygenic photosynthesis
(c) Aerobic respiration
(d) Oxygenic photosynthesis
Oxygenic photosynthesis
- Which organisms are able to use glucose for carbon and energy?
(a) Photoautotroph
(b) Photoheterotroph
(c) Chemolithotroph
(d) Chemoheterotroph
Chemoheterotroph
- Which of the following is not a structure for survival in prokaryotes?
(a) Flagella
(b) Glycogen
(c) Endospores
(d) Inorganic polyphosphate inclusions
Flagella
- Most phototrophs are:
(a) Autotrophic
(b) Heterotrophic
(c) Organotrophic
(d) Chemotrophic
Autotrophic
- Which of the following would grow best in dry conditions?
(a) Osmophile
(b) Xerophile
(c) Halophile
(d) Psychophile
Xerophile
- Which of the following techniques best determines the number of total bacteria?
(a) Plate count
(b) Most probable number measurement
(c) Turbidity measurements
(d) None of the above
Turbidity measurements
- When undertaking a colony count:
(a) It is assumed that each colony arose from one cell
(b) Only viable cells are counted
(c) The organisms must be able to grow on solid media
(d) All of the above
All of the above
- Which of the following is not a function of the cytoplasmic membrane?
(a) It retains the cytoplasm
(b) It acts as a selectively permeable barrier
(c) It maintains the various shapes of bacteria
(d) It is the location of various metabolic processes, such as respiration and photosynthesis
It maintains the various shapes of bacteria
- Carrier mediated transport is necessary when:
(a) Diffusion will not allow adequate amounts of a substance to enter a cell
(b) Movement of a substance is against the concentration gradient
(c) The level of solutes is higher inside a cell than outside a cell
(d) All of the above
All of the above
- By which of the following mechanisms can a cell transport a substance from a lower to a higher concentration?
(a) Simple diffusion
(b) Active transport
(c) Facilitated diffusion
(d) Any of the above
Active transport
- Cilia on the outer cell surface of some protozoa are used for:
(a) Cell motility
(b) Sexual reproduction
(c) Adherence to surfaces
(d) Adherence and exchange of genetic material
Cell motility
- A scrapping of material from a person’s tooth revealed many bacteria on the tooth surface. Such bacteria remain attached to the tooth surface by structures called
(a) pili
(b) capsules
(c) glycocalyx
(d) all of the above
all of the above
- The membrane of a gas vesicle is composed of
(a) various phospholipids.
(b) protein.
(c) carbohydrate.
(d) both glycoproteins and phospholipids.
protein.
- The diether molecule within the membrane structure of the __________ yields a lipid __________.
(a) Archaea / bilayer
(b) Archaea / monolayer
(c) Bacteria / bilayer
(d) Bacteria / monolayer
Archaea / monolayer
- When does endospore formation in bacteria commence?
(a) when bacterial growth ceases due to limitation of an essential nutrient
(b) when the bacterium is undergoing binary fission
(c) when bacteria are in the lag phase
(d) following bacterial death
when bacterial growth ceases due to limitation of an essential nutrient
- Bacterial generalized transduction differs from specialized transduction in that generalized transduction
(a) Kills the host.
(b) Transfers DNA from one cell to another.
(c) Transfers specific DNA segments.
(d) Involves lysogeny.
Transfers specific DNA segments.
- Which of the following processes requires contact between donor and recipient cells?
(a) Transduction
(b) Transcription
(c) Transformation
(d) Conjugation
Conjugation
- F– strains of Escherichia coli
(a) Do not have an F factor
(b) Have the F factor as a plasmid
(c) Have an integrated F factor
(d) Transfers the F factor to other strains at a high frequency
Do not have an F factor
- Which of the following is NOT true about Hfr x F– matings?
(a) The recipient can become F+ (or Hfr) if the mating lasts long enough for the entire bacterial chromosome to be transferred.
(b) The recipient usually remains F– because the connection usually breaks before the entire bacterial chromosome can be transferred.
(c) The recipient may become F+ if more than half of the plasmid is transferred.
(d) All of the above are true about Hfr x F– matings.
The recipient may become F+ if more than half of the plasmid is transferred.
- Which of the following can be evolutionary chronometers?
(a) Fossilised remains of microorganisms
(b) Macromolecules measuring change in organisms over time
(c) Universally distributed, functionally homologous molecules in organisms
(d) All of the above
All of the above
- What most likely was the earliest cellular process on Earth?
(a) Chemolithotrophy
(b) Fermentation
(c) Oxygenic photosynthesis
(d) Aerobic respiration
Chemolithotrophy
- Extreme environments like deep ocean hydrothermal vents contain organisms similar to the first organisms that evolved on Earth. These organisms are:
(a) Psychrophilic Archaea
(b) Methanogenic Archaea
(c) Thermoacidophilic Bacteria
(d) Hyperthermophilic Archaea
Hyperthermophilic Archaea
- Ribosomal RNA sequencing has enabled:
(a) A distinct third domain in the tree of life to be identified
(b) A reclassification of the tree of life based on molecular traits
(c) A more definitive form of identification of microbes to be achieved
(d) All of the above
All of the above
- The most useful form of sterilisation in terms of relative effectiveness and wide-spread applications is:
(a) Incineration
(b) Autoclaving
(c) Irradiation
(d) Ultra high temperature (UHT)
Autoclaving
- Which of the following would not be used to control bacteria in industrial products?
(a) Irradiating products
(b) Storing at low temperatures
(c) Addition of mercuric compounds
(d) Addition of preservatives
Addition of mercuric compounds
- Which of the following are important considerations when trying to eliminate microorganisms from an object by a particular control method?
- Initial size of the microbial population
- Structural characteristics of the microbes
- Nature of the object being treated
- Dosage of the treatment agent
- Exposure time to the treatment agent
(a) All (b) 1, 2, 3, 4 (c) 1, 2, 4, 5 (d) 1, 2, 3
(a) All
- Which of the following is best to sterilise heat-labile solutions:
(a) Chlorine
(b) Autoclaving
(c) Hot air oven
(d) Membrane filtration
Membrane filtration
- Thermal death point is referred to as the:
(a) Minimum time to kill all microbes at a specified temperature
(b) Time that ensures there is less than 10-6 probability of cells surviving
(c) Lowest temperature required to kill all microbes in 10 minutes
(d) Minimum time to kill 90% of the organisms in a population at a specified temperature
Lowest temperature required to kill all microbes in 10 minutes
- Decimal reduction time is referred to as the:
(a) Minimum time to kill all microbes at a specified temperature
(b) Time that ensures there is less than 10-6 probability of cells surviving
(c) Lowest temperature required to kill all microbes in 10 minutes
(d) Minimum time to kill 90% of the organisms in a population at a specified temperature
Minimum time to kill 90% of the organisms in a population at a specified temperature
- Cephalosporin is an antibiotic produced by the fungus Acremonium chrysogenum. What does it target in the cell?
(a) Cell wall synthesis
(b) Protein synthesis
(c) Nucleic acid synthesis
(d) Synthesis of essential metabolites
Cell wall synthesis
- Spirochetes are unusual bacteria because they are able to move using:
(a) Pseudopodia
(b) Peritrichous flagella
(c) Axial filaments
(d) Cilia
Axial filaments
- Purple and green bacteria are:
(a) Chemolithotrophs
(b) Chemoheterotrophs
(c) Oxygenic phototrophs
(d) Anoxygenic phototrophs
Anoxygenic phototrophs
- Yeasts are classified as:
(a) Bacteria
(b) Fungi
(c) Protozoa
(d) Archaea
Fungi
- In general, fungi derive nutrients through:
(a) Photosynthesis
(b) Engulfing bacteria
(c) Absorbing organic substrates
(d) Parasitism
Absorbing organic substrates
- Methanogens are found in which grouping:
(a) Gram positive bacteria
(b) Proteobacteria
(c) Archaea
(d) All of the above
Archaea
- ____________ are toxic proteins released from the pathogen as it grows.
(a) Endotoxins
(b) Exotoxins
(c) Macrotoxins
(d) Microtoxins
Exotoxins
- A ________ is a disease that primarily infects animals but can be transmitted to humans.
(a) nosocomial infection
(b) zoonosis
(c) vector infection
(d) fomite
zoonosis
- For which of the following bacterial diseases/infections would penicillin therapy prove completely ineffective?
(a) Strep sore throat caused by Streptococcus pyogenes
(b) Meningitis caused by Neisseria meningitidis
(c) Pneumonia caused by Mycoplasma pneumonia
(d) Gas gangrene caused by Clostridium perfringens
Pneumonia caused by Mycoplasma pneumonia
- Major virulence factors in Gram negative bacteria are endotoxins, which are also known as:
(a) Enterotoxins
(b) Haemolysins
(c) Lipopolysaccarides
(d) All of the above
Lipopolysaccarides
- Which of the following statements about E.coli is not true:
(a) It can be used as an indicator organism for water quality
(b) It can cause food poisoning
(c) It is part of the normal flora of the human gastrointestinal tract
(d) All of the above are true
All of the above are true
Question 1 (10 marks)
Briefly define each of the following terms (2 mark each):
(a) Chemoheterotroph
(b) Autoclaving
(c) Halophile
(d) Phylogeny
(e) Glycocalyx
CHECK LECTURE NOTES
Question 2 (6 marks)
Discuss EITHER (a) or (b) (diagrams can be used):
(a) Describe the general structure of a virus. What are the types of genomes can viruses can have?
OR
(b) The differences between bacterial cytoplasmic and outer membranes.
CHECK LECTURE NOTES
Question 3 (6 marks)
Answer any 3 of the following 5 short answer questions (2 marks each):
(a) What are two characteristics of endospores?
(b) What is a frameshift mutation?
(c) Briefly explain how psychrophiles adapt to low temperature.
(d) Why are most antibiotics ineffective against viruses, fungi and protozoa?
(e) What are two potential drawbacks to the use of ionizing radiation in food preservation?
CHECK LECTURE NOTES
Question 4 (4 marks)
Gene transfer processes are important for microbes gaining new traits.
Discuss the key features for EITHER of the following mechanisms of gene transfer:
(a) Conjugation
OR
(b) Transduction
CHECK LECTURE NOTES
Question 5 (6 marks)
Answer any 3 of the following 4 short answer questions (2 marks each):
(a) Briefly explain the endosymbiotic theory.
(b) What were the most likely early cellular processes on Earth?
(c) Name 2 medically important Enteric Bacteria (to a species level)
(d) Give examples of lactic acid bacteria that are important (i) medically and (ii) industrially
CHECK LECTURE NOTES
Question 6 (6 marks)
Discuss EITHER (a) or (b):
(a) Bacterial respiration
OR
(b) Bacterial photosynthesis
CHECK LECTURE NOTES
Question 7. (6 marks)
Answer ALL of the following (1 mark each)
State True or False for (a) – (d)
(a) Viruses generate energy by carrying out respiration.
(b) Porins are channels in the outer membrane of gram negative bacteria.
(c) The transport of a substance into the cell by facilitated diffusion requires energy.
(d) Some substances, for example sulfur, can be both an electron acceptor and electron donor in respiration processes.
Fill in the blanks for (h) - (j)
(e) Antimicrobial activity of a chemical is measured by determining the smallest amount of agent needed to inhibit the growth of a test organism, a value called the ________________________.
(f) In the control of pathogens,________________ are applied to living tissues; and_________________ are used on inanimate objects.
CHECK LECTURE NOTES
Question 8 (6 marks)
Discuss EITHER (a) or (b):
(c) What are genotypic and phenotypic characteristics of bacteria? Briefly describe two examples of each.
OR
(d) What are the 4 main targets of antibiotics in bacterial cells. Briefly describe the mechanism of attack of two antibiotics that targeting different site in the cell.
CHECK LECTURE NOTES
