Basic Microbiology Objectives


Lec 01 – History of Microbiology
True or False
1. Robert Koch is the Father of Microbiology. False.
2. The first recorded observation of microorganisms was in the nineteenth century.
3. Oliver Wendell Holmes was one of the first scientists to imply that hand washing
might be important in preventing infection during childbirth. True.
4. Boiling surgical instruments was a common practice in the early 1800s for
reducing infection. False.
5. The scientist responsible for discovering the fermenting properties of
microorganisms was Louis Pasteur. True.
Provide the terms or phrase that makes the statement correct.
1. The postulates that were proposed to determine the etiology of disease were
formulated by ____________________. (Robert Koch).
2. What mouthwash on the market today is a testament to one of the pioneers of
antiseptic technique ________________? (Listerine)
3. The last man to finally demonstrate the absurdity of spontaneous generation was
___________________. (Pasteur)
4. One of the first compounds used as an antiseptic for wound dressings was
______________________ (Carbolic acid)
5. The solid support used in microbiological media is called ______________.
1. The clarity of an image seen microscopically is determined by the ____________ of
the microscope. (resolving power)
2. More parallel light rays can enter the objective lens if __________ is placed between
the specimen and the objective. (immersion oil)
3. The organic molecule imparting color to a dye is called a(n) ____________.
4. The staining of the background surrounding a microbial cell is called ___________
staining. (negative)
5. The charge on the bacterial surface is __________ because of the presence of many
__________ groups. (negative) (carboxy-1)
6. The most important of the differential stains is the __________ stain. (Gram)
7. In ___________ microscopy the background appears dark while the microbial cell
appears bright and transparent. (darkfield)
8. At magnifications of 1000 X the ____________ microscope allows due to distinguish
objects in the microbial cell because of their density. (phase contrast)
9. The light source for the fluorescent microscope is a(n) ____________ lamp, whereas
a(n) ______________ lamp is used for brightfield microscopy. (mercury vapor)
10. The electron microscope uses _____________ instead of the glass lens system used in
brightfield microscopy. (electromagents)


Lec 02 – Germ Theory of Disease
1.Which of the following is not one of Pasteur’s contributions?
(a) Provided evidence for the germ theory with his association of specific microbes with
certain diseases in silkworms
(b) Developed the first rabies vaccine
(c) Developed the technique of pasteurization to cure sour wine
(d) Developed a cowpox vaccine for smallpox
(e) Contributed to the emerging science of immunology with the study of chicken cholera
in chickens
2.The germ theory of disease states that:
(a) Microorganisms that invade other organisms can cause disease in those organisms
(b) Microorganisms can spontaneously arise in debilitated hosts
(c) Microorganisms do not cause infectious diseases
(d) Not all microorganisms are harmful
(e) Malaria is caused by bad air
3. Put Koch’s postulates in order.
(a) The disease organism must be isolated in pure culture.
(b) The disease organism must be recovered from the inoculated animal.
(c) The specific causative agent must be found in every case of the disease.
(d) Inoculation of a sample of the culture into a healthy, susceptible animal must produce
the same disease.
4.Match the following scientists who emerged in specialized fields of microbiology to their famous contributions and specialized field:
I. Metchinikoff
II. Beijerinck
III. McClintock
IV. Ehrlich

1. Mobile (‘‘jumping’’) genes
2. Salvarsan against syphilis
3. Cellular immunity (phagocytes)
4. Infectious filtrates contain viruses.
5. Less than 1% of microorganisms are harmful and cause disease. True or false?
6. Life on earth would be much better if all microbes were eradicated. True or false?

Lec 03 – Protection against Infection
1.Match the following types of antimicrobials with their actions:
___ Bacteriostatic
___ Germicidal
___ Viricidal
___ Sporicidal
___ Fungicidal
___ Bacteriocidal
a) Kills microbes
(b) Inactivates viruses
(c) Kills bacteria
(d) Stops bacterial growth
(e) Kills bacterial endospores and fungal spores
(f) Kills yeasts and molds
2. Which term is used to describe the reduction in numbers of pathogenic organisms on objects or in materials so that they do not pose a disease threat?
(a) Sanitization
(b) Sterilization
(c) Disinfection
(d) Decontamination
(e) Lyophilization
3. Which of the following is true of the phenol coefficienttest?
(a) Uses Salmonella typhi and Staphylococcus aureus
(b) Uses phenol as the standard chemical against which other chemicals are compared
(c) If a chemical has a phenol coefficient less than 1.0, it is less effective than phenol
(d) It is particularly reliable for chemicals derived from phenol
(e) All of these
4.The pasteurization process does which of the following in milk?
(a) It kills all microbes.
(b) It inactivates viruses.
(c) It kills all bacterial spores.
(d) It kills microbial pathogens that might be present in milk.
(e) It sterilizes milk.
5. The advantage of UV-radiation disinfection is that it readily penetrates through most samples. True or false?
6. Which of the following are reasons why UV light might be expected to be less
effective in killing bacteria?
(a) UV light cannot penetrate glass, cloth, paper, or most materials under which microbes
might be located.
(b) UV light can penetrate air.
(c) Small DNA-binding proteins in bacterial spores make the DNA resistant to UV light
(d) UV light sources gain intensity over time.
(e) UV light kills fewer bacteria than expected because of their DNA repair mechanisms.
7. Quaternary ammonium compounds (quats) are a type of:
(a) Soap
(b) Alkylating agent
(c) Detergent
(d) Phenolic substance
(e) Basic solution
8. The active antimicrobial ingredient in bleach is:
(a) Phenol
(b) Hydrochloride
(c) Hypochlorite
(d) Iodine
(e) Bromide
9. Match the following chemical antimicrobial agents to their uses in combating
___ Phenol derivatives
___ Iodine
___ Alcohols
___ Acids
___ Chlorine
___ Oxidizing agents
___ Nitrates
(a) Food preservation
(b) Puncture wound disinfection
(c) Skin disinfection
(d) Instrument disinfection
(e) Water disinfection
10. Heat-sensitive materials (rubber and plastic) and bulky materials (mattresses) can be sterilized using:
(a) Dry heat
(b) Autoclaving
(c) UV radiation
(d) Gaseous ethylene oxide
(e) None of these
11. In the process of autoclaving it is the increased temperature and not the increased  pressure that kills all microbes, including spores and the nucleic acids of viruses.  True or False?
12. The minimum time used for sterilization by autoclaving is:
(a) 5 minutes
(b) 15 minutes
(c) 45 minutes
(d) 1 hour
(e) 2 hoursMicrobiology

Lec 04 – Metabolism in Bacteria
1. The most fundamental difference between prokaryotes and eukaryotes is the
presence of a nuclear membrane in ____________ and its absence in ___________.
(eukaryotes) (prokaryotes)
2. Movement to or away from a chemical stimulus is called _________. (chemotaxis)
3. The type of symbiosis in which both partners benefit is called ________.
4. Members of the same species that possess different characteristics are called
___________. (strains)
5. A classification scheme based on evolutionary changes is called ___________.
6. The analysis of 16S rRNA is used to determine the ________ relatedness of
different species. (evolutionary)
7. The differentiated cell type of cyanobacteria that is resistant to environmental stress
is called a(n) ____________. (akinete)
8. Flagella-like filaments involved in motility but not exposed to the external
environment can be found in the bacterial group called ________. (spirochetes)
9. The microorganism found in extreme environments that are devoid of a true
peptidoglycan layer are called the ____________. (archaebacteria)
10. The cytoplasmic membrane system of eukaryotes is called the ____________.
(endoplasmic reticulam)
11. The shorter versions of flagella in eukaryotes are called ________. (cilia)
12. Amebas can produce cytoplasmic projections called _________. (pseudopodia)
13. Some fungi can exist in two morphological states, a condition referred to as
___________. (dimorphism)
14. The opening in some protozoa through which food is ingested is called the
__________. (cytosome)
15. The well walls of __________ are composed almost entirely of silicon dioxide.
16. ___________ is a characteristic polysaccharide found in the cell walls of fungi as
well as of many algae. (Cellulose)
17. The mycelia of fungi that penetrate the host to obtain nutrients are called
___________. (haustoria)
18. Organisms that live on dead material are called ____________. (saprobes)Microbiology

Lec 05 – ATP Generation
1. The nonusable energy produced during a chemical reaction is referred to as
_________. (entropy)
2. Organisms that obtain their energy from preformed organic or inorganic
molecules are called ____________. (chemotrophs)
3. A positive G implies that the reaction requires energy and is ___________.
4. The anaerobic breakdown of glucose to pyruvic acid is called __________.
5. Methane can be oxidized by a certain group of microorganisms called
___________. (methyltrophs)
6. The pathway that supplies reduced NADP for biosynthesis is called the
_______________ or pentose phosphate pathway. (hexose monophosphate
7. The first electron carrier in the respiratory chain is usually a(n) ____________.
8. The formation of ATP during the transport of electrons and hydrogen to oxygen is
called _______________. (oxidative phosphorylation)
9. Energy is released when electrons travel from a more ____________ source to a
more ____________ substance. (negative) (positive)
10. Hydrocarbons such as alkanes are ultimately oxidized to __________ by
microorganisms. (fatty acids)
Multiple choice
Select the appropriate letter that correctly answers the question or completes the
1. Which of the following statements concerning photosystems is not true?
a. The photolysis of water results in the formation of carbon
b. ATP formation may be cyclic or noncyclic.
c. Both photosystems are not always present in some bacteria.
d. Chlorophyll is one of the light-harvesting pigments
e. NADP is one of the electron carriers.
1. Carbon dioxide is fixed to which of the following molecules during
photosynthesis to produce carbohydrate?
a. ribulose 1,5-diphosphate d. ribose 5-phosphate
b. glyceraldehyde 3-phosphate e. erythrose 4-phosphate
c. glucose 6-phosphate
2. Certain molecules or structures in the cell are used to quench the overproduction
of oxygen during photosynthesis and are called
a. phycobilisomes d. tetrapyrroles
b. carboxysomes e. phycobiliproteins
c. isoprenoids
3. Species of Thiobacillus are noted for their ability to oxidize
a. inorganic nitrogen compounds d. hydrogen gas
b. hydrocarbons e. sulfur compounds
c. methane
4. One of the principal organic electron acceptors during anaerobic respiration is
a. pyruvate d. formaldehyde
b. lactate e. fumarate
c. acetate

Lec 06 – Microbial Metabolism
1. What is a catalyst?
a. a synthesis of cell molecules and structures
b. a substance that speeds up a reaction
c. where the substrate binds to on an enzyme
d. organic compound that alters a substrate
2. An enzyme _______ the activation energy required for a chemical reaction.
a. increases
b. converts
c. lowers
d. catalyzes
3. Which of these types of organisms gets its organic nutrients and energy from another
a. chemoheterotroph
b. chemoautotroph
c. photoheterotroph
d. photoautotroph
4. What is the chemical pathway that uses glucose and oxygen to produce carbon dioxide
and water?
a. aerobic cellular respiration
b. fermentation
c. photosynthesis
d. oxidative phosphorylation
5. Where does the electron transport system take place in bacteria?
a. cell membrane
b. mitochondria
c. ribosome
d. cytoplasm
6. Where do the substrates bind on an enzyme?
a. allosteric site
b. active site
c. amino acid site
d. enzymatic site


Lec 07 – Lytic and Lysogenic Cycles
1. The classification of viruses is based primarily on __________ and
____________ composition and structure. (morphology) (nucleic acid)
2. Bacterial viruses are called _______ or simply _________. (bacteriophage)
3. The complete and infective viral particle is called a(n) ________. (virion)
4. The protein cost surrounding the virus is called a(n) ___________, which is made
up of smaller protein units called ________. (capsid) (capsomeres)
5. The nucleic acid found in fungal viruses is only _____________. (RNA)
6. The maximum number of capsomeres that have been found in viruses is _______,
and the smallest number is __________. (252) (12)
7. The peplomers on the influenza virus envelope are ________ and __________.
(hemagglutinin) (neuraminidase)
8. The lesions produced by animal viruses on embryonic membranes are called
____________. (pocks)
Lec 08 – Viroids, Prions
1. A compound frequently used to inactive viruses for use in vaccines is
a. ethylene glycol d. ether
b. isopropy1 alcohol e. chloroform
c. formaldehyde
1. Which of the following characteristics is not associated with viruses?
a. They can be cultivated on artificial media as long as ATP is
b. Nucleic acid may be single-stranded or double-stranded DNA or
c. They can be inactivated only at temperatures above 100° C.
d. They use the ribosomes of the cell to make viral protein.
e. They show absolute specificity for one type of host.
1. Which of the following characteristics would not be appropriate for use in viral
a. nucleic acid type
b. capsid symmetry
c. presence or absence of an envelope
d. number of capsomeres
e. all of the above
1. Which of the following best describes a viroid?
a. Nucleocapsid has icosahedral symmetry, is an RNA virus, and
causes disease in plants.
b. It has no protein coat, is an RNA virus, and causes disease in
c. It has no protein coat, is a DNA virus, and causes disease in plants.
d. It has no protein coat, is a RNA virus, and causes disease in plants.
e. None of the above is appropriate.
1. Which of the following agents would not inactivate most viruses?
a. 40% ethyl alcohol d. phenol
b. 37° C for 15 minutes e. formaldehyde
c. 2% glutaraldehyde
1. The viruses that exhibit complex capsid symmetry are
a. Adenovirus d. smallpox virus
b. T4 bacteriophage e. none of the above
c. Influenza virus

Lec 09 – Bacterial Genetics
1. The enzyme used by organisms for the synthesis of DNA is called DNA
_________ and the enzymes used to degrade DNA are called _________.
(polymerase) (nucleases [exonucleases and endonucleases])
2. The DNA strand from which a complimentary molecule is synthesized is called
the _____________ strand. (primer)
3. Bidirectional DNA synthesis occurs primarily in _________ whereas
unidirectional DNA synthesis is more frequently observed in __________.
(prokaryotes and eukaryotes) (viruses)
4. The group of enzymes that aids in the interconversion of relaxed and superhelical
forms of DNA are called ____________. (topoisomerases)
5. The rolling circle mechanism of replication is an example of ___________
replication. (unidirectional)
6. The term used to describe multiple copies of DNA that are joined together is
______________. (concatameric)
7. Sex factor plasmids that can be integrated into the chromosome are called
____________. (episomes)
8. Proteins produced by the bacterial cell that are toxic to related species are called
____________. (bacteriocins)
9. Any chemical agent capable of altering the genotype and possibly the phenotype
of the cell is called a(n) ____________. (mutagen)
1. Short sequences of DNA that can “jump” from one DNA site to another have been
called ___________ sequences. (insertion)
Multiple choice
Select the appropriate letter that correctly answers the question or completes the
1. The test used to determine the carcinogenic potential of a chemical is called the
a. reversion test d. replica plating test
b. Ames test e. none of the above
c. insertion frequency test
2. A mutant having a requirement for a certain growth factor is called a(n)
a. protptroph d. chemotroph
b. autotroph e. auxotroph
c. heterotroph
3. The technique used to demonstrate that microbial mutants can arise spontaneously
in the absence of various chemical or physical agents is called the
a. Ames test d. Kornberg assay
b. transformation technique e. none of the above
c. replica plating technique
4. DNA synthesized discontinuously produced short fragments called
a. Ames fragments d. Okazaki fragments
b. Kornberg sequences e. none of the above
c. insertion sequences
5. The enzyme that catalyzes the union of the DNA fragments synthesized
discontinuously is called
a. DNA gyrase d. DNA polymerase III
b. DNA helicase e. DNA ligase
c. DNA polymerase I
Lec 10 – Gene Expression
1.Which of the following is not characteristic of the lactose operon?
a. The lactose repressor molecule does not require a corepressor.
b. The operon is under positive as well as negative control
c. The repressor molecule genes are in the same operon.
d. The lactose structural genes are in the same operon.
e. The lactose genes code for enzymes involved in a catabolic
2. The “wobble” hypothesis refers to
a. The inability of certain tRNAs to stabilize themselves on the
b. The flexibility of the codon-anticodon interaction at the third
codon position.
c. The loose binding of codons that do not specify an amino acid.
d. None of the above.
3. The type of mutation that would cause a change in the reading frame from CAT
CAT CAT CAT . . . to CAT ATC ATC ATC . . . is called a(n)
a. insertion d. transversion
b. deletion e. none of the above
c. transition
1. The catabolite activator protein (CAP) functions in the cell to
a. repress the synthesis of biosynthetic enzymes
a. bind a catabolite and prevent repressor from attaching to the
promoter region
b. bind a catabolite and prevent RNA polymerase from binding to the
promoter region
c. bind cyclic AMP and attach to the promoter region
d. none of the above
1. Pribnow sequences are believed to carry out which of the following functions in
the cell?
a. site for binding of rho and termination of mRNA synthesis
b. site for attachment of N-formylmethionine
c. initiation site for DNA replication
d. site on the DNA for binding the sigma subunit of RNA
e. site for attachment of repressor on the operator
1. Which of the following characteristic is associated with tRNA molecules?
a. They have a CCA end to which is attached an amino acid.
b. They have abnormal bases such as pseudouracil and
c. They have a cloverleaf appearance.
d. They have a site for binding aminoacy1 tRNA synthetases.
e. All of the above are true.
1. The name given to mRNA to which several ribosomes are attached is
a. monocistronic d. polygenic
b. polycistronic e. none of the above
c. polysome
2. Which of the following nucleic acids has the fewest nucleotides?
a. tRNA d. mRNA
b. rRNA e. DNA
1. The area on the DNA that codes for a polypeptide is called a(n) ____________.
2. A genetic code in which more than one code word specifies a single amino acid is
called ____________. (degenerate)
3. The product of structural gene activity that facilitates the binding of an
aporepressor to the operator is called the ___________. (corepressor)
4. The enzymes that catalyze the attachment of amino acids to their specific tRNA
molecules are called __________. (aminoacy1 tRNA synthetases)
5. The triplet on the tRNA molecule that is complimentary to a triplet on the mRNA
is called a(n) ______________. (anticodon)
6. The component of the RNA polymerase enzyme that is specifically involved in
initiating mRNA synthesis is called the ____________. (sigma factor)
7. Messenger RNAs that contain information for more than one polypeptide are
called _____________. (polycistronic)
8. The energy for translocation in protein synthesis is derived from the hydrolysis of
____________. (GTP)
Lec 12 – Recombination in Bacteria
1. Virus that integrates into the host genome is called a(n) _________. (provirus)
2. _________ is the process in which there is movement of certain genes from one
DNA molecule to another. (Transposition)
3. The process in which cell-free DNA is taken up by a cell and engages in genetic
recombination is called _________. (transformation)
4. The bridge formed between conjugants during the conjugation progress is called
a(n) ___________. (pilus)
5. The gene transfer mechanism in which bacterial information is carried by a virus
is called ___________. (transduction)
6. The inverted repeat sequences found on the ends of certain DNA units are called
_______________. (palindromic)
7. Plasmids that are composed of DNA from more than one source are called
_________. (chimeric)
8. The amlification of a gene in a microbial cell in which the gene has been dervied
from another source is called _____________. (cloning)
9. The gene transfer mechanism in bacteria in which there is a cone-way transfer
between two mating types is called _______________. (conjugation)
10. The crossover event between lambda and the host chromosome during the
excision of lambda often results in the formation of a lambda particle carrying the
bacterial genes _______ and _______. (galactose [Ga1]) (biotin [Bio])

Lec 13 – Soil Microbiology
1. The group of organisms most frequently associated with the production of antibiotics is
(a) Actinomyces (b) Klebsiella (c) Streptomyces (d) Pseudomonas
2. Which type of organism most frequently dominates the soil in terms of total biomass?
(a) Bacteria (b) Fungi (c) Algae (d) Protozoa
3. The soil element that is most responsible for limitations of plant growth and food production is
(a) oxygen (b) nitrogen (c) phosphorous (d) sulphur
4. The term ‘rhizosphere’ was coined by
(a) Winogradsky (b) Beijerinck (c) Hiltner (d) Waksman
5. The rate of organic matter decomposition is measured by,
(a) Dilution plate count method (b) Carbon‐di‐oxide evolution method
(c) Conn’s direct microscopic method (d) None of the above
6. One characteristic of the rhizosphere region of the soil ecosystem is its high
(a) oxygen content (b) microbial count (c) macropore count (d) humus content
7. Carbon cycles relatively rapidly except when it is
(a) dissolved in freshwater ecosystems (b) released by respiration
(c) stored in petroleum, coal or wood (d) part of bicarbonate reservoir in oceans
8. Contact slide or buried slide technique for qualitative determination of soil microflora was given by
(a) Winogradsky (b) Rossi and Cholodney (c) Beijerinck (d) Dobereiner
9. Fastest decomposition rate in soil is expected with residues having
(a) lowest N content (b) widest C:N ratio (c) lowest C:N ratio (d) highest C content
10. Which pool in the global carbon cycle uses biochemical energy from reduced carbon
(a) heterotrophs (b) autotrophs (c) carbon dioxide (d) soil organic matter
11. A free living non‐symbiotic Gram negative dinitrogen fixing bacteria
(a) Azospirillum (b) Anabaena (c) Azotobacter (d) Rhizobium
12. Conversion of organic complex of an element in to its inorganic state is called
(a) Mineralization(b) Immobilization (c) Nitrification (d) Oxidation
13. Adding nitrogen fertilizer to a compost pile will ____ the decomposition rate and ______ humus production.
(a) increase, increase (b) slow, increase (c) increase, decrease (d) slow, decrease
14. The element associated with dinitrogen reductase in diazotrophs is
(a) Oxygen (b) Magnesium (c) Molybdenum (d) Cobalt
15. The process that converts gaseous nitrogen to compounds that can be used by the biological community is called
(a) mineralization (b) nitrogen fixation (c) nitrogen mobilization (d) ammonification
16. Which pool in the nitrogen cycle can be both fixed and nitrified?
(a) humus (b) ammonium (c) Nitrogen (d) nitrate
17. Sulfur metabolism is an important part of energy metabolism in which of the following groups of microorganisms?
(a) phototrophic bacteria (b) Enterobacteriaceae (c) cyanobacteria (d) Pseudomonadaceae
18. An example of bacteria oxidizing ammonia to nitrites is
(a) Pseudomonas (b) Bacillus (c) Rhizobium (d) Nitrosomonas
19. The actinomycete that fixes atmospheric nitrogen in association with non‐leguminous plants is
(a) Actinomyces (b) Streptomyces (c) Nocardia (d) Frankia
20. The term mycorrhizae describes a symbiotic relationship between
(a) a heterotroph and an autotroph (b) an antibiotic and a pathogen
(c) nitrification and denitrification (d) a bacteria and a fungus
State whether the following statements are TRUE or FALSE
_______ 1. Microbial enzyme activities depends on soil pH.
_______ 2. Soil is unique with solid, liquid and gaseous phases interacting and thus supports more number and types of microflora.
_______ 3. Soil protozoa balances the soil ecosystem by feeding on soil fungi.
_______ 4. Bacteria which grows at higher soil temperatures are barophiles.
_______ 5. The classification of viruses is based primarily on morphology and nucleic acid
composition and structure.
_______ 6. The mycelia of fungi that penetrate the host to obtain nutrients are called haustoria.
_______ 7. An example of an associatively symbiotic nitrogen fixing bacterium is Azotobacter.
_______ 8. Thiobacillus is involved in transformation of both nitrogen and iron.
_______ 9. The major group of organisms surrounding the root of plants are true bacteria.
_______ 10. Lignin is broken down in the soil primarily by fungi.
Fill in the blanks with appropriate words
1. The autotrophic mode of nutrition in bacteria was first established by __________.
2. An _________ pH favours growth of soil fungi.
3. Cellulose is polymer of _______________.
4. The rate of decomposition of organic matter is measured by ___________ method.
5. Soil microbial activity can be quantified by determining the __________ enzyme activity.
6. _______________ in root nodules regulates the supply of oxygen.
7. The site of nitrogen fixation in blue green algae is __________.
8. The primary wood degrading microorganisms are _________.
9. A non filamentous bacteria capable of sulphur oxidation is __________.
10. The region around leaf surface is called __________

Lec 14- Environmental Microbiology
1. Which of the following is not a major subdivision of the biosphere?
a. hydrosphere c. stratosphere
b. lithosphere d. atmosphere
2. A/an is defined as a collection of populations sharing a given habitat.
a. biosphere c. biome
b. community d. ecosystem
3. The quantity of available nutrients from the lower levels of the
energy pyramid to the higher ones.
a. increases c. remains stable
b. decreases d. cycles
4. Photosynthetic organisms convert the energy of into chemical energy.
a. electrons c. photons
b. protons d. hydrogen atoms
5. Which of the following is considered a greenhouse gas?
a. CO2 c. N2O
b. CH4 d. all of these
6. The Calvin cycle operates during which part of photosynthesis?
a. only in the light c. in both light and dark
b. only in the dark d. only during photosystem I
7. Root nodules contain , which can .
a. Azotobacter, fix N2
b. Nitrosomonas, nitrify NH3
c. rhizobia, fix N2
d. Bacillus, denitrify NO3
8. Which element(s) has/have an inorganic reservoir that exists
primarily in sedimentary deposits?
a. nitrogen c. sulfur
b. phosphorus d. b and c
9. The floating assemblage of microbes, plants, and animals that drifts on
or near the surface of large bodies of water is the community.
a. abyssal c. littoral
b. benthic d. plankton
10. An oligotrophic ecosystem would be most likely to exist in a/an
a. ocean c. tropical pond
b. high mountain lake d. polluted river
11.Which of the following does not vary predictably with the depth of
the aquatic environment?
a. dissolved oxygen
b. temperature
c. penetration by sunlight
d. salinity
12. Which of the following would be least accurate in detecting coliform
bacteria in a water sample?
a. the presumptive MPN test
b. the standard plate count
c. the membrane filter method
d. the confirmatory MPN test

Lec 15 – Microbiology of Food
1. The time required to kill a specified number of microorganisms at a particular
temperature is called the ____________. (thermal death time [TDT])
2. Canned foods are thermally processed in steam-heated vats called
_____________. (retorts)
3. The species of Vibrio associated with shellfish poisoning is ___________.
(V. parahemolyticus)
4. The organisms responsible for the spoilage (called rope) of bread is
____________. (Bacillus subtilis)
5. Fatal forms of food poisoning are more frequently caused by the microorganism
____________. (Clostridium botulinum)
6. Food handlers are the most frequent source of food poisoning caused by
____________. (Staphylococcus aureus)
7. The principal viral agent associated with foodborne illness is the _____________.
(hepatitis A virus)
8. The animal parasite associated with foodborne illness and resulting from the
ingestion of undercooked bear or other wild meats is ______________.
(Trichinella spiralis)
The recently discovered cause of bacterial foodborne illness that is associated with cereal
dishes is ____________. (Bacillus cereus)
1. Which of the following species or genera is a frequent contaminant of water
supplies ?
a. Lactobacillus d. Clostridium
b. Streptococcus e. Bacillus
c. Pseudomonas
2. Contemporary milk pasteurization times and temperatures have been selected
because they will destroy
a. Mycobacterium tuberculosis d. Bacillus anthracis
b. Coxiella burnetii e. Legionella pneumophilia
c. Streptococcus faecalis
3. The majority of “swollen” cans observed in the marketplace are the result of
a. CO2 production by clostridia
b. H2 production by clostridia
c. H2 production from the interaction of tin and acid
d. O2 production by aerobic sporeformers
e. None of the above
1. The microorganisms most frequently involved in the spoilage of canned foods are
a. Streptococci and lactobacilli
b. Leuconostoc and Pseudomonas
c. Clostridium and Bacillus
d. Saccharomyces and Staphylococcus
e. Lactobacillus and Streptococcus
1. If an organism has a water activity of 0.62, in which of the following foods (water
activity in parentheses) will it most likely grow?
a. flour (0.61) d. honey (0.50)
b. chocolate (0.54) e. dried beef (0.87)
c. fresh meat (0.98)
2. The predominant group of microorganisms found in milk today are
a. mycobacteria d. lactobacilli and streptococci
b. Brucella e. Clostridium and Bacillus
c. Gram-negative rods
Lec 16- Role of Bacteria in Fermentation
1. During fermentation, pyruvic acid is converted into major organic products such as
(A) glucose and maltose (B) starch and cellulose
(C) ethyl alcohol and lactic acid (D) citric acid and isocitric acid
2. The group of organisms most frequently associated with the production of antibiotics is
(A) Actinomyces (B) Klebsiella
(C) Streptomyces (D) Pseudomonas
3. Maximum production of antibiotics generally occurs
(A) during the log phase (B) after the log phase
(B) before the log phase (D) only when the pH drops below 4.3
4. The Koji process is a technique used in the industrial production of
(A) vinegar (B) microbial polysaccharides
(C) pectinase (D) single cell protein
5. The precursor added to a fermenting medium for penicillin G production is
(A) malic acid (B) tryptophan
(C) yeast extract (D) lysine
State true or False:
6. Baffles are provided in a fermentor for mixing and turbulence.
7. A type of bacterial growth where the cells never reach its stationary phase is batch
8. Mushroom production is an example of solid state fermentation.
9. Strict sterile conditions are not required in lactic acid production because the organism
can be cultivated at a high temperature.
10. A most common mutagen used for strain improvement of industrial microbes is IR rays.
Fill up the blanks:
11. The device used to maintain cells in logarithmic state in a fermentor is called as
12. Aspergillus niger is used for the industrial production of ____________.
13. The organism used in recombinant DNA technology for the commercial production of
interferon, insulin and growth hormones is ____________.
14. The classical approach to strain improvement of industrially important strain is
15. The method for screening antibiotic producing microorganisms is called ___________.
Match the following:
16. Saccharomyces cerevisiae : (a) Amylase
17. Abhya gossypii : (b) SCP
18. Scenedesmus : (c) Streptomycin
19. Bacillus amyloliquifaciens : (d) Ethanol
20. Streptomyces griseus : (e) Riboflavin

Lec 17 – Beneficial Microorganisms in Agriculture
1. The major morphological group of bacteria found in the soil is
a. long rods, non-spore-forming
b. cocci
c. rods, spore-forming
d. coccoidal rods
e. rods, gram-positive non-spore-forming
1. Which type of organisms most frequently dominates the soil in terms of total
a. Bacteria c. algae
b. Fungi d. protozoa
1. The actinomycete that fixes nitrogen in association with nonleguminous plants is
a member of the genus
a. Actinomyces d. Arachnia
b. Streptomyces e. Nocardia
c. Frankia
2. The bacterial inhabitant of the soil that can parasitize other bacteria belongs to the
a. Erwinia d. Bdellovibrio
b. Rhizobium e. Bacillus
c. Frankia
3. The rhizosphere and rhizoplane are surrounded by a microbial community whose
cell density is
a. greater than 108/g c. approximately 107/g
b. approximately 105/g d. less than 105/g
4. The major group of microorganisms found surrounding the roots of plants are
a. algae d. fungi
b. true bacteria e. protozoa
c. actinomycetes
5. The primary purpose of the rhizosphere community is to
a. destroy potential invading plant pathogens
b. supply amino acids to the plant
c. reduce the level of toxic acids that surround the plant roots
d. convert organic compounds containing nitrogen, phosphorous,
and sulfur to inorganic products suitable for assimilation by the plant
e. convert inorganic compounds of nitrogen, phosphorous, and sulfur
to organic products suitable for growth of the plant
Choose the best answer:
1. The rate of organic matter decomposition is measured by,
(a) Dilution plate count method (b) Carbon‐di‐oxide evolution method
(c) Conn’s direct microscopic method (d) None of the above
2. Which of the following substance is most resistant to microbial biodegradation?
(A) pectin (B) cellulose
(C) lignin (D) hemicellulose
3. Which pool in the global carbon cycle uses biochemical energy from reduced carbon
(A) heterotrophs (B) autotrophs
(C) lithotrophs (D) organotrophs
16. Fastest decomposition rate in soil is expected with residues having
(A) lowest N content (B) widest C:N ratio
(C) lowest C:N ratio (D) highest C content
17. Adding nitrogen fertilizer to a compost pile will _________ the decomposition rate and
___________ humus production.
(A) increase, increase (B) slow, increase
(C) increase, decrease (D) slow, decrease
Define the following or answer in one sentence:
18. Humic acid
19. Mesophiles
20. Herbicide
21. Biogas
22. Vermiculture
Fill up the blanks:
23. Conversion of organic complex of an element in to its inorganic state is called
24. Soil microbial activity can be quantified by determining the __________ enzyme activity.
25. The organism most frequently dominates the soil in terms of total numbers and types
are ____________.
26. The increase in concentration of a recalcitrant molecule as it passes through the trophic
levels is called ______________.
27. Those compounds, both biological and synthetic, that are resistant to microbial
digestion are called ____________ molecules.
Match the following:
16. Phanerochate chrysosporium : (f) Methane producer
17. Pseudomonas putida : (g) Cellulose degrader
18. Methanothrix : (h) Pesticide degrader
19. Streptomyces : (i) Wood degrading fungi
20. Trichoderma : (j) Compost pits


Lec 32 – Microbial Products
Nitrite is converted into nitrate by the bacteria
173. Phycobiont is
a. The algal part in Lichens
b. The fungal part in Lichens
c. Laustoria formation
d. None of these
174. Parasitic form must contain
a. Capsules b. Cell-wall c. Endospores d. Flagella
175. The total no. of genes in the group of same individuals is
a. Nitrosomonas c. Nitrobacter
b. Nitrosocytes d. Azatobacter
165. Sulphur oxidizing bacteria is
a. Alcaligenes b. Pseudomonas c. Thiobacillus d. None of these
166. Bacillus Schlegelli is
a. Hydrogen – Oxydising bacteria
b. Sulphur – Oxydising bacteria
c. Iron-Oxidising bacteria
d. Nitrite oxidizing bacteria
167. The group of bacteria which deopends on organic sources in nature
for their energy requirements. They are said to be a. Chemotrophs
b. Phototrophs c. Heterotrophes d. Organotrophs
168. Majority of bacteria are
a. Genome c. Gene pool
b. Gene mapd. None of these
a. Saprophytes c. Commensals
169. Symbionts are
b. Symbionts d. Parasites
176. Transformation was observed mainly in
a. Bacteriophages b. Temperate phages c. –phage d. All of these
177. Capsulated forms of bacteria are
a. Virulent b. A virulent c. Useful d. Symbiotic
178. The bacterial cells participating in conjugation are
a. Bacteria in symbiotic association
b. The group of fungi in symbiotic association
c. The groups participating in symbiotic association
d. All of these
170. The best example for symbiotic associa- tion is
a. E.coli in intestine of man
b. Lichens
c. Normal floraof skin
d. All of the above
171. The enzymes responsible for decomposi- tion is
a. Conjugants c. Exconjugants
179. Phagocytes are
a. Monocytes c. Basophils
b. Fertile cellsd. None of these
b. Macrophages d. All of these
a. Lipolytic c. Lysozyme
b. Proteolyticd. Both a and b
180. The microorganism engulfed by phago- cyte resides in a vacuole is
known as
a. Phagosome b. Lysosomec. both a and b d. None of these
181. Toxic products in phagolysosome are
a. H2SO4
b. Singlet O2
c. Superoxide radicals
d. All of these
182. During destruction of antigen particle in phagolysosome the product
formed in phagolysosome the product formed during formulation is
a. Acetic acid b. Lactic acidc. Citric acid d. None of these
172. Urea is decomposed by the species
a. Micrococcus sps. b. Nitrosomonas sps. c. Proteus sps. d. Both a and c

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