PRACTICE EXAM 1 Flashcards
- Louis Pasteur was first to show that living organisms did not arise from non-living
material. The concept that living organisms arose from non-living material was called:
(a) Biogenesis
(b) Fermentation
(c) Pasteurisation
(d) Spontaneous generation
Spontaneous generation
- Who of the following was the first to observe and accurately describe microorganisms?
(a) Joseph Lister
(b) Antoine van Leeuwenhoek
(c) Edward Jenner
(d) Robert Koch
(e) Louis Pasteur
Antoine van Leeuwenhoek
- The ultimate limits or usefulness of a microscope is defined by:
(a) Refractive index
(b) Resolution
(c) Magnification
(d) Light intensity
Resolution
- The protein coat and the genome of a virus is called the:
(a) Capsid
(b) Virion
(c) Envelope
(d) Nucleocapsid
Nucleocapsid
- Viruses that attack bacteria are known as
(a) Bacterial consumers.
(b) Bacteriophages.
(c) Microphages.
(d) Viroids.
Bacteriophages.
- You suspect a 100-nm structure is present in a cell. Which of the following provides the lowest magnification that you can use to see this structure?
(a) Fluorescence microscope
(b) Phase contrast microscope
(c) Electron microscope
(d) Confocal scanning microscope
Electron microscope
- Fermentation uses which of the following mechanisms for energy generation:
(a) Substrate level phosphorylation
(b) Oxidative phosphorylation
(c) Photophosphorylation
(d) Chemiosmosis
Substrate level phosphorylation
- An organism that uses light energy, H2S as an electron donor, and CO2 as a sole carbon source is:
(a) Chemolithotrophic and autotrophic
(b) Chemoorganotrophic and heterotrophic
(c) Phototrophic and autotrophic
(d) Phototrophic and heterotrophic
Phototrophic and autotrophic
- Which of the following techniques best determines the number of viable bacteria?
(a) Microscopic count
(b) Plate count
(c) Turbidity measurements
(d) None of the above
Plate count
- A microorganism that grows without using oxygen but is not inhibited by the presence of oxygen is termed a/an:
(a) Obligate anaerobe
(b) Facultative anaerobe
(c) Aerotolerant anaerobe
(d) Microaerophilic aerobe
Aerotolerant anaerobe
- A culture medium consisting of agar, human blood, and beef heart is a:
(a) Complex medium
(b) Defined medium
(c) Selective medium
(d) Differential medium
Complex medium
- Magnetosomes in bacteria help cells:
(a) Attach to metal objects
(b) To magnetically attach to each other
(c) To float on the surface of fresh water ponds
(d) To orient in the earth’s magnetic field
To orient in the earth’s magnetic field
- The major component of the Gram negative cell wall is:
(a) A thin layer of peptidoglycan
(b) Lipopolysaccharide
(c) Pseudopeptidoglycan
(d) A thick layer of peptidoglycan
A thin layer of peptidoglycan
- A major distinguishing characteristic of Archaeal phospholipids is the presence of:
(a) Ester linkages
(b) Ether linkages
(c) Hydrophobic fatty acids
(d) Sterols
Ether linkages
- Which of the following is important in initial attachment and subsequent development of biofilms?
(a) Magnetosomes
(b) Glycocalyx
(c) Cysts
(d) Axial filaments
Glycocalyx
- Lysozyme induces lysis in bacteria because it interferes with:
(a) Integrity of the linkage between N-acetylglucosamine and N-acetylmuramic acid
(b) Cell membrane permeability
(c) Synthesis of the linkage between the amino acids chains in the peptidoglycan layer
(d) Synthesis of N-acetylmuramic acid
Integrity of the linkage between N-acetylglucosamine and N-acetylmuramic acid
- Which of the following is true of capsules?
(a) They help bacteria resist phagocytosis by host phagocytic cells
(b) They protect bacteria from desiccation
(c) They prevent the entry of bacteriophages
(d) All of the above are true of capsules
All of the above are true of capsules
- A bacterium with a single flagellum extending out from each end of the cell is called:
(a) Monotrichous
(b) Lophotrichous
(c) Amphitrichous
(d) Peritrichous
Amphitrichous
- Which of the following mechanisms does not require energy for the transport of a substance into the cell?
(a) Facilitated diffusion
(b) Active transport
(c) Group translocation
(d) Cytosis
Facilitated diffusion
- Which external structure allows the transfer of DNA?
(a) Pili
(b) Cilia
(c) Fimbrae
(d) Axial filaments
Pili
- Which of the following is not true about plasmids:
(a) Replicate independently of the chromosome
(b) Permit bacteria to store additional genetic information
(c) Are not essential to normal cell functions
(d) They code for regulatory functions only
They code for regulatory functions only
- Consider conjugation in Escherichia coli. In which of the following matings would chromosomal genes be transferred most frequently?
(a) F+ × F-
(b) F- × F-
(c) Hfr × F-
(d) Hfr × F+
Hfr × F-
- In an isotonic environment, Gram negative bacteria treated with lysozyme will:
(a) Form spheroplasts
(b) Form protoplasts
(c) Burst
(d) Plasmolyse
Form spheroplasts
- In general, which of the following are most sensitive to penicillin?
(a) Gram negative bacteria
(b) Mycoplasma group of bacteria
(c) Gram-positive bacteria
(d) Archaea
Gram-positive bacteria
- How do Spirochaetes differ structurally from other bacteria?
(a) Have no cell wall
(b) Are acid fast
(c) Are endospore-formers
(d) Are tightly coiled spiral-shaped cells
Are tightly coiled spiral-shaped cells
- Which concentration of ethanol is the most effective disinfectant?
(a) 100%
(b) 70%
(c) 40%
(d) 10%
70%
- Which of the following could be used as an evolutionary chronometer?
(a) Universally distributed macromolecules in organisms
(b) Functionally homologous macromolecules in organisms
(c) Fossilised remains of microorganisms
(d) All of the above
All of the above
- Molecular sequencing suggests that chloroplasts arose from a group of prokaryotic intracellular parasitic organisms within which of the following phyla
(a) Firmicutes
(b) Cyanobacteria
(c) Crenarchaeota
(d) Proteobacteria.
Cyanobacteria
- Microorganisms inhabiting environments with conditions closest to those on primitive Earth are most likely to be:
(a) Bacteria
(b) Eukarya
(c) Archaea
(d) Protozoa
Archaea
- What is the most important tool in bacterial taxonomy?
(a) Lipid profiling
(b) DNA base composition
(c) 16S ribosomal RNA sequencing
(d) Biochemical testing
16S ribosomal RNA sequencing
- Using binomial nomenclature e.g. Escherichia coli, the first name (Escherichia) designates the:
(a) Family
(b) Order
(c) Species
(d) Genus
Genus
- What major evolutionary finding has emerged from the study of ribosomal RNA?
(a) The discovery of Archaea as a separate Domain
(b) Genetic material in the first forms of life was RNA
(c) Bacteria were the first organisms to evolve
(d) Prokaryotic and eukaryotic cells are different
The discovery of Archaea as a separate Domain
- The earliest stromatolites were probably:
(a) Anoxygenic phototrophs
(b) Oxygenic phototrophs
(c) Anoxygenic heterotrophs
(d) Oxygenic heterotrophs
Anoxygenic phototrophs
- Which of the following would not be an example of a phenotypic characteristic?
(a) Profile of lipids in the cytoplasmic membrane of an organism
(b) Nucleotide sequence of an essential gene of an organism
(c) Optimum temperature for growth of an organism
(d) All of them are phenotypic characteristics
Nucleotide sequence of an essential gene of an organism
- You have isolated a prokaryotic cell. Normally the first step in identification would be a(n)
(a) Gram stain
(b) Lactose fermentation test
(c) Endospore stain
(d) Flagella stain
Gram stain
- Which of the following groups are not found in the domain Archaea?
(a) Aerobes
(b) Pathogens
(c) Anaerobes
(d) Methanogens
Pathogens
- Which of the following is not true about aseptic technique:
(a) A microbiological technique used to remove all living microbes from equipment and media
(b) A microbiological technique used to prevent contamination by unwanted microbes
(c) The manipulation of sterile equipment and media to maintain the sterile conditions
(d) A microbiological technique used to prevent unwanted spreading of microbes, particularly pathogens
A microbiological technique used to remove all living microbes from equipment and media
- The type of filter used when a syringe, pump, or vacuum is used to force the liquid through the filtration apparatus into a sterile collection vessel is called
(a) Depth filter.
(b) Membrane filter
(c) Nucleation track filter.
(d) Microbistat filter.
Membrane filter
- A sulfa drug such as sulfonamide is a chemotherapeutic agent that affects bacteria by disrupting which process?
(a) Peptidoglycan synthesis
(b) Folic acid synthesis
(c) Protein synthesis
(d) DNA replication
Folic acid synthesis
- The most likely reason why some microbes produce antibiotics is because:
(a) Antibiotics are simply end products of metabolism
(b) These microbes have been genetically manipulated to do so for human use
(c) Antibiotics are a storage of nutrients used when nutrient levels in the environment are low
(d) These microbes are common soil inhabitants producing antibiotics to eliminate competitors
These microbes are common soil inhabitants producing antibiotics to eliminate competitors
- Which is not a reason why bacteria may have an inherent natural resistance to an antibiotic?
(a) It may be impermeable to the antibiotic
(b) It may be able to pump out an antibiotic entering the cell
(c) It may be able to alter the antibiotic to an inactive form
(d) It may be protected from the drug by its nuclear membrane
It may be protected from the drug by its nuclear membrane
- Which is a common genus of bacteria that forms endospores?
(a) Staphylococcus
(b) Streptococcus
(c) Bacillus
(d) Mycobacteria
Bacillus
- Mycobacterium infections are difficult to treat because:
(a) Mycobacteria multiply too rapidly once inside host cells
(b) Waxy mycoloic acids make mycobacteria resistant to the penetration of water soluble antibiotics
(c) Mycobacteria remain undetected by the host immune system
(d) These microbes are common soil inhabitants producing antibiotics to eliminate competitors
Waxy mycoloic acids make mycobacteria resistant to the penetration of water soluble antibiotics
- Which of the following statements is true regarding Legionnaires’ disease?
(a) Human-to-human spread is common
(b) Legionella pneumophila microbes reside in air conditioning systems in large numbers
(c) Antibiotics are ineffective against Legionella pneumophila
(d) Legionella pneumophila is responsible for the majority of pneumonias in normally healthy adults
Legionella pneumophila microbes reside in air conditioning systems in large numbers
- Which of the following diseases is NOT normally spread by a common source?
(a) Diphtheria
(b) Foodborne diseases
(c) Waterborne diseases
(d) Cholera
Diphtheria
- Which of the following is not a genus of lactic acid bacteria?
(a) Bacillus
(b) Streptococcus
(c) Lactobacillus
(d) Enterococcus
Bacillus
- Actinobacteria are a phylogenetically distinct group of Gram positive bacteria because they:
(a) Ferment lactic acid
(b) Are chemoorganotrophic
(c) Are intracellular parasites
(d) Produce branched cells or fungal-like structures such as mycelia, hyphae and reproductive spores
Produce branched cells or fungal-like structures such as mycelia, hyphae and reproductive spores
- All members of the phylum Proteobacteria:
(a) Are gram negative
(b) Are opportunistic pathogens
(c) Inhabit gastrointestinal tracts
(d) All of the above
Are gram negative
- The genus Bacillus is a heterogenous group of bacteria. Which of the following is a Bacillus species not responsible for:
(a) Anthrax disease
(b) Bioinsecticides
(c) Antibiotic production
(d) Responsible for all of these
Responsible for all of these
- Which of the following is an endotoxin?
(a) An AB toxin produced by E.coli
(b) A superantigen produced by Staphylococcus aureus
(c) The lipid A portion of lipopolysaccharide in Gram negative bacteria
(d) Toxins produced by Gram negative bacteria that cause damage in the small intestine
The lipid A portion of lipopolysaccharide in Gram negative bacteria
Question 1 (8 marks)
Answer ANY four (4) out of the following six (6) questions (2 marks each)
i. What are the types of phototophic microorganisms and how do they differ?
ii. Give two differences between aerobic and anaerobic respiration.
iii. Name 2 methods of counting total bacteria.
iv. What is the difference between a mesophile and a psychrophile?
v. What is the difference between a food infection and intoxication? Give an example of a bacterium causing each.
vi. Give two examples of diseases transmitted through direct host-to-host.
CHECK LECTURE NOTES
Question 2 (6 marks)
Answer EITHER of the following (8 marks):
(a) Draw the typical growth curve of a bacterial population in a batch culture and label the phases of growth. Describe what occurs in each phase.
OR
(b) What are the three types of exotoxins. Briefly describe the mechanism of action of one example. How do exotoxins compare with endotoxins?
CHECK LECTURE NOTES
Question 3 (6 marks)
Answer EITHER of the following, note diagrams can be used (6 marks):
(a) Describe the structure of a Gram negative cell envelope.
OR
(b) Describe the possible structures of an enveloped virus.
CHECK LECTURE NOTES
Question 4 (10 marks)
Answer ANY five (5) out of the following seven (7) questions (2 marks each)
i. What is the present view on the origins of life in Earth?
ii. What is an evolution chronometer, give an example?
iii. Name 2 genera that produce endospores.
iv. What are the two forms of radiation used for sterilizing bacteria and how do they differ?
v. What is the difference between a disinfectant and an antiseptic?
vi. Name 2 factors influencing the effectiveness of microbial control procedures.
CHECK LECTURE NOTES
Question 5 (6 marks)
Answer EITHER of the following, note diagrams can be used (6 marks):
(a) Structure and importance of endospores.
OR
(b) Structure and types of bacterial flagella.
CHECK LECTURE NOTES
Question 6 (8 marks)
Answer EITHER (a) OR (b).
(a) Penicillins were the first antibiotic group to be discovered and since then the activity and rates of production have improved dramatically.
i. Briefly outline the industrial production of penicillin. (3 marks)
ii. In production, how is the type of penicillin produced be varied? (2 marks)
iii. Explain why the yield of penicillin antibiotics produced from microbes has increased dramatically since these antibiotics were first discovered.(3 marks)
OR
(b) Common source transmission can result in significant disease outbreaks.
i. What are two common source transmission types? (2 marks)
ii. Compare common source to host-to-host transmissions. (3 marks)
iii. Briefly discuss a disease often caused through common source transmission. (3 marks)
CHECK LECTURE NOTES
Question 7. (6 marks)
Match the following statements to the correct bacterium:
i. Bacterium that is Beta-haemolytic and causes pharyngitis
ii. Obligate intracellular parasite
iii. One of the leading producers of antibiotics
iv. Acid fast bacterium causing Hansen’s disease
v. Spirochete that causes lyme disease
vi. Industrially important ethanol producing yeast
(a) Mycobacterium leprae
(b) Borrelia burgdorferi
(c) Saccharomyces cerevisiae
(d) Chlamydia trachomatis
(e) Streptococcus pyogenes
(f) Streptomyces griseus
CHECK LECTURE NOTES
