Review Questions and Answers | Môn Microbiology - Trường Đại học Quốc tế, Đại học Quốc gia Thành phố Hồ Chí Minh

lOMoAR cPSD| 58504431 Quiz 1
1. Some kinds of microorganisms are known as extremophiles. Which of the habitats
below will not provide optimal conditions for these microorganisms? A. Hot springs B. Deep ocean floor C. Human Body D. Salt mines
2. Which of the experiment of Louis Pasteur defeats the concept of spontaneous generation: A. Petri disks experiment B. Postulate experiment
C. Swan-necked flask experiment D. Closing tube experiment
3. In the presence of oxygen, all types of microorganisms can survive. A. True B. False
4. Who is the first person observed unicellular organisms, which he called “animalcules”,
using a microscope he developed? A. Ferdinand Cohn
B. Antonie van Leeuwenhoek C. Louis Pasteur D. Robert Koch
5. What is the concept of spontaneous generation?
A. Bacterial growth is the division of one bacterium into two daughter cells in a process called binary fision.
B. Microorganisms developed from seeds or germs that entered the food from air.
C. The time it takes for bacteria to double in number.
D. Microorganisms arose from nonliving materials. 6. A pure culture
A. is a population of identical cells. B. is sterile. C. is a streaked agar plate. D. is made of defined medium.
7. Which concept did Robert Kock develop and support direct experimental support? lOMoAR cPSD| 58504431 A. Concept of pathogen
B. Concept of infectious animal C. Concept of diseased animal
D. Concept of infectious disease
8. Who discovered that the mold Aspergillus metabolized D-tartrate? A. Louis Pasteur B. Pier Antonio Micheli C. Antonie van Leeuwenhoek D. Robert Koch
9. The influence of Ferdinand Cohn on microbiology is a system of bacterial classification
and … method for preventing the contamination. A. UV B. Alcohol C. Filtration D. Heating
10. A bacteria uses compounds such as sugars, amino acids, or organic acids. as its carbon
source. It also contains pigments that convert light energy into ATP. What is the most
accurate nutritional category of this bacteria? A. Photoautotrophs B. Photoheterotrophs C. Chemoorganotrophs D. Chemoautotrophs
11. Which of the following statement is FALSE?
A. Animal cells exist only as parts of multicellular structures.
B. Microorganisms are all single-celled organisms and exclude the viruses.
C. Microorganisms carry out their life processes independently of other cells.
D. Plant cells are unable to live alone in nature. Quiz 2
1. Which is/are a function(s) of the cytoplasmic membrane in prokaryotes?
A. It functions as a permeability barrier.
B. It is an anchor for many proteins involved in bioenergetic reactions and transport.
C. It is a major site of energy conservation.
D. It serves as a permeability barrier, a docking station for proteins involved in bioenergetics
reactions and transport, and a site for energy conservation. lOMoAR cPSD| 58504431
2. Which has the rod-shape cell? A. Bacilli B. Cocci
C. Sprilli D. None of the above
3. The pictures below show colorized micrographs of SARS-CoV-2 virus particles (A:
orange, B: green) in the infection process to different cell lines. (Credit: NIAID IRF-Frederick)
These micrographs are taken by which types of microscope? (Note that the
original images are black and white, color is added by manipulating them in a computer) A: Light microscope, B: TEM
A: Fluorescence microscope, B: SEM A: SEM, B: TEM A: TEM, B: SEM
4. Archaea and Bacteria are prokaryotes because they don’t have ________ which
are presented in Eukarya, such as golgi. A. membranes B. nuclei
C. membrane-enclosed organelles Sai
D. nuclei and membrane-enclosed organelles
5. In what/which domain(s) of life is/are microorganisms represented? lOMoAR cPSD| 58504431 A. Archaea
B. Archaea, Bacteria, and Eukarya C. Eukarya D. Bacteria
6. The minimum resolution of a light microscope is about 0.2 μm meaning that
A. Two objects that are less than 0.2 μm apart cannot be resolved as distinct and separate.
B. Two objects that are more than 0.2 μm apart cannot be resolved as distinct and separate.
C. The minimum size of bacteria can be seen under the microscope is 0.2 μm. Sai
D. The maximum size of bacteria that this microscope can magnify is 0.2 μm. 7. Which is not Eukaryotes? A. Algae B. Fungi C. Virus D. Protozoa
8. Which statement below is false?
A. The life processes of all cells are governed by their complement of genes, their genome.
B. Eukaryotic cells typically have much smaller genomes than prokaryotes.
C. Evolution occurs in any self-replicating system in which variation occurs as the result of
mutation and selection and differential fitness is a potential result.
D. The evolutionary relationships between organisms are the subject of phylogeny
9. Which one does not have the nucleus? A. Archaea B. Fungi C. Protists D. None of the above
10. The table below lists the cell size of some bacteria, from the largest to the
smallest ("Brock Biology of Microorganisms," 15th edition, Table 2.1, adapted).
Assume each of these bacteria will be cultured in its optimal conditions. Which of
bacterial cells tend to grow fastest? lOMoAR cPSD| 58504431 A. Epulopiscium fishelsoni B. Magnetobacterium bavaricum C. Escherichia coli D. Pelagibacter ubique
11. Energy can be obtained from some sources in nature such as A. organic chemicals. B. inorganic chemicals. C. light D. All of the answers. Quiz 3
1. Which of the following statements is FALSE?
A. Proteins dominate the macromolecular composition of a cell.
B. Growth factors differ from trace metals in that they are organic (rather than metallic) macronutrients.
C. In a differential media, an indicator is added to determine if a certain metabolic response has
taken place during growth by changing the medium's color.
D. Plates inoculated from a contaminated pure culture will usually contain more than one colony type.
2. The endotoxin, a toxic portion of the lipopolysaccharide (LPS) layer, is found ONLY in the cell surface of A. gram-positive Bacteria.
B. gram-negative Bacteria. C. Archaea. D. Eukarya.
3. In gram-positive Bacteria, the cell walls are composed mainly of thick ________ layers. A. protein
B. poly-β-hydroxybutryic acid (PHB) C. lipopolysaccharides (LPS) D. peptidoglycan
4. Which type of microscopy below could be used to observe different layers of the cell walls? A. bright-field microscopy B. phase-contrast microscopy C. SEM D. TEM lOMoAR cPSD| 58504431
5. Which is/are a function(s) of the cytoplasmic membrane in prokaryotes?
A. It functions as a permeability barrier.
B. It is an anchor for many proteins involved in bioenergetic reactions and transport.
C. It is a major site of energy conservation.
D. It serves as a permeability barrier, a docking station for proteins involved in bioenergetics
reactions and transport, and a site for energy conservation.
6. Gram staining method is based on differences in A. Bacteria and Archaea. Sai
B. prokaryotic and eukaryotic cells.
C. bacterial cells with different types of cell walls.
D. archaeal cells with different types of metabolism.
7. Which of following statement is FALSE?
A. Prokaryotes tend to survive and adapt more rapidly to extreme and dynamic environmental conditions than eukaryotes.
B. A bacterial cell is interpreted as gram-positive when it forms purple insoluble crystal violet-
iodine complexes within the cell during the Gram stain.
C. Porins are channels in the outer membranes of gram-positive Bacteria.
D. Smaller prokaryotic cells generally grow faster than larger ones due to a higher surface-area- to-volume ratio.
8. Which of the following statements is TRUE?
A. Fimbriae are generally shorter and more numerous than flagella.
B. Fimbriae enable cells to stick to surfaces. sai
C. Pili serve as receptors and facilitate genetic exchange between prokaryotic cells.
D. Fibriae are usually shorter than flagella and enable cells to adhere to surfaces, whereas pili
are involved in genetic exchange.
9. What is the function of endospores?
A. They help bacteria reproduce
B. They increase the ability of bacteria to live in extreme conditions C. They transport toxins. D. All of the above Sai
10. The wavelengths of visible light are much greater than that of electrons. This is
the reason why electron microscopy has larger ________ than light microscopy A. penetration B. resolution C. magnification D. contrast lOMoAR cPSD| 58504431
11. The .... is responsible for the structural strength of the cell A. cytoplasmic membrane B. cell wall C. ribosome D. cytoplasm.
12. Glycolysis is the first stage of glucose metabolism, which is a fundamental
process that supplies energy. The figure below shows the allosteric regulation of glucose metabolism.
Which of the following is the case of feedback inhibition?
A. Insulin is released, promotes phosphofructokinase-2 kinase activity to produce high level of
fructose 2,6-bisphosphate. Sai
B. Phosphofructokinase-1 is inhibited by high level of ATP and citrate.
C. Cell’s energy stores are low.
D. Phosphofructokinase-1 is activated by high level of AMP and fructose 2,6-bisphosphate. Sai
13. Which of the following processes is an example of catabolic pathway?
A. Production of DNA, RNA, nucleotides from nucleotide precursors.
B. Anaerobic breakdown of glucose or other substrates to products like lactic acid or ethanol.
C. Assembly of peptide crosslinks and glycan chains for peptidoglycan cell walls.
D. Glucose synthesis from non-carbohydrate precursors.
14. When observing a bacterial cell by an electron microscope, three different layers
around the cell can be seen. This cell could be ________ and would have
________ color after Gram stain process. A. gram-positive / purple
B. gram-negative / pink C. gram-positive / pink D. gram-negative / purple lOMoAR cPSD| 58504431 QUIZ 4 (11.11.2023)
1. Which of following statement is FALSE?
a. A bacterium that lacks an arginine biosynthetic pathway would stil be able to make
proteins with arginine and grow only if arginine is supplemented into the growth medium.
b. With respect to nitrogen utilization, relatively few bacteria can use NH3
whereas many more can make use of N2.
c. Defined media are prepared by adding individual "pure" chemicals in known
quantities. Complex media needs only to contain one undefined product to be
considered complex or undefined.
d. The energy released from the hydrolysis of coenzyme A is conserved in the synthesis of ATP.
2. Which of following statement is FALSE?
a. Growth factors are always organic compounds, including vitamins, amino acids, purines, and pyrimidines.
b. Complex media contain at least one undefined product to be considered complex or undefined.
c. An isolate could grow in a nutrient medium without amino acids but grows
faster on an amino-acid-added medium. This statement suggests that amino
acids are trace nutrients for this isolate.
d. Defined media are prepared by adding individual "pure" chemicals in known quantities.
3. Which feature of anaerobic and aerobic respiration is different between the two catabolic strategies? a. electron donor b. use of electron transport c. use of proton motive force d. electron acceptor
4. Glycolysis is the breakdown of ___ a. ADP b. Carbohydrate c. ATP d. Protein
5. Where does electron transport of cellular respiration happen within the cell of a bacterium? a. Cytoplasm b. Mitochondria c. Plasma membrane d. Nucleus
6. Which of following statement is FALSE?
a. Bacterial colonies can be of various shapes and sizes depending on the organism,
the culture conditions, the nutrient supply, and several other physiological parameters.
b. Calcium helps stabilize cell walls in many microorganisms lOMoAR cPSD| 58504431
c. Colonies are visible masses of cells formed from the subsequent division of one or a few cells
d. Plates that contain more than one colony type are indicative of a pure culture.
7. Fermentation has a relatively low ATP yield compared to aerobic respiration because
a. more reducing equivalents are used for anaerobic catabolism.
b. oxidative phosphorylation yields a lot of ATP.
c. less ATP is consumed during the first stage of aerobic catabolism.
d. substrate-level phosphorylation yields a lot of ATP.
8. Which parts of aerobic cellular respiration generate the carbon dioxide?
a. Synthesis of acetyl coa & electron transport
b. Synthesis of acetyl coa & Kreb's cycle
c. Glycolysis & synthesis of acetyl coa
d. Glycolysis & electron transport
9. Anabolic reactions are when ____
a. Microorganisms consume each other
b. One molecule transfers a monomer to another
c. Smaller molecule result from the breakdown of larger molecules
d. Larger molecule are synthesized from small molecules
10. Which of following statement is TRUE?
a. Different organisms need different complements of nutrients, and all nutrients are required in the same amounts.
b. MacConkey agar is a culture medium designed to grow Gram negative bacteria
and differentiate them for lactose fermentation
c. Semisolid media are prepared by lower the temperature of liquid media.
d. Freshwater species are usually unable to grow in the absence of sodium
11. If yeast, sugar and water are mixed together, the yeast wil metabolize the sugar. If this
process takes place in a sealed container, the bubbles produced during fermentation wil
be trapped. What substance are these bubbles made of? a. biotin production.
b. carbon dioxide produced by fermentation. c. oxidative phosphorylation. d. oxygen being released.
*To define whether an unknown microorganism is a eukaryote or a prokaryote, you use
simple stain and light microscope method. The stained cells on control slide, which is known
as a eukaryote, can be seen. However, the cells of your unknown microorganism cannot be
observed. What can you conclude from this experiment?
a. The stain kil ed the unknown microorganism so it could not be visualized under the microscope.
b. The unknown organism is a virus. Sai
c. The cells of the unknown organism maybe smaller than the control.
d. The unknown organism is a prokaryote. lOMoAR cPSD| 58504431
To ensure growth of a newly discovered bacterium with unknown nutritional requirements, it
would be best to begin with a ________ medium rather than a ________ medium. a. selective / differential b. selective / complex c. minimal / complex d. complex / minimal
Although the inner leaflet of the gram-negative outer membrane is composed mainly
of phospholipids, the outer leaflet of the outer membrane contains A. pseudopeptidoglycans. B. lipoteichoic acids.
C. poly-β-hydroxybutyric acids (PHB).
D. lipopolysaccharides (LPS).
Which of following element is a micronutrient? A. iron B. vitamin B12 C. arginine
D. inorganic phosphorous
*Which of following statement is FALSE?
A. For many organisms, knowledge of the exact composition of a medium is not essential.
B. Different organisms need different complements of nutrients, and all nutrients are
required in the same amounts.
C. Differential media are quite useful for distinguishing between species of bacteria. Sai
D. Freshwater species are usually able to grow in the absence of sodium
● Which of following statement is FALSE?
A. A selective medium contains compounds that selectively inhibit the growth of some Sai
B. Cells produce siderophores that bind calcium and transport it into the cell.
C. Differential media are quite useful for distinguishing between species of bacteria.
D. Bacteria usually grow faster in the laboratory conditions than in nature
● Some intestinal pathogens such as Salmonella, Shigella, and Escherichia
could cause mild to severe symptoms due to the presence of A. endospores sai B. lipopolysaccharides. C. S-layers. lOMoAR cPSD| 58504431 D. peptidoglycan.
The cytoplasmic membrane could best be described as
A. a highly selective permeability barrier.
B. an impermeable barrier.
C. a passive conduit for intracellular transport.
D. a rigid structure that protects the cell.
… works as a stabilizer of ribosomes, nucleic acids as well as an enzyme cofactor. A. potassium B. hydrogen C. zinc D. magnesium Quiz 5
1. If yeast, sugar and water are mixed together, the yeast will metabolize the
sugar. If this process takes place in a sealed container, the bubbles produced
during fermentation will be trapped. What substance are these bubbles made of? A. biotin production.
B. carbon dioxide produced by fermentation. C. oxidative phosphorylation. D. oxygen being released.
2. Which feature of anaerobic and aerobic respiration is different between the two catabolic strategies? A. electron donor B. use of electron transport C. use of proton motive force D. electron acceptor
3. Which of following statement is TRUE?
A. MacConkey agar is a culture medium designed to grow Gram negative bacteria and
differentiate them for lactose fermentation
B. Semisolid media are prepared by lower the temperature of liquid media.
C. Freshwater species are usually unable to grow in the absence of sodium Sai lOMoAR cPSD| 58504431
D. Different organisms need different complements of nutrients, and all nutrients are required in the same amounts.
4. Glycolysis is the breakdown of ___ A. ATP B. ADP C. Carbohydrate D. Protein
5. Which of following statement is FALSE?
A. A bacterium that lacks an arginine biosynthetic pathway would still be able to make proteins
with arginine and grow only if arginine is supplemented into the growth medium. Sai
B. With respect to nitrogen utilization, relatively few bacteria can use NH3 whereas many
more can make use of N2.
C. Defined media are prepared by adding individual "pure" chemicals in known quantities.
Complex media needs only to contain one undefined product to be considered complex or undefined.
D. The energy released from the hydrolysis of coenzyme A is conserved in the synthesis of ATP.
6. Which of following statement is FALSE?
A. Plates that contain more than one colony type are indicative of a pure culture.
B. Colonies are visible masses of cells formed from the subsequent division of one or a few cells
C. Calcium helps stabilize cell walls in many microorganisms
D. Bacterial colonies can be of various shapes and sizes depending on the organism, the culture
conditions, the nutrient supply, and several other physiological parameters.
7. Which parts of aerobic cellular respiration generate the carbon dioxide?
A. Glycolysis & synthesis of acetyl coa
B. Synthesis of acetyl coa & Kreb's cycle
C. Synthesis of acetyl coa & electron transport
D. Glycolysis & electron transport
8. Anabolic reactions are when ____
A. One molecule transfers a monomer to another
B. Microorganisms consume each other
C. Larger molecule are synthesized from small molecules
D. Smaller molecule result from the breakdown of larger molecules
9. Fermentation has a relatively low ATP yield compared to aerobic respiration because lOMoAR cPSD| 58504431
A. more reducing equivalents are used for anaerobic catabolism. Sai
B. oxidative phosphorylation yields a lot of ATP.
C. less ATP is consumed during the first stage of aerobic catabolism.
D. substrate-level phosphorylation yields a lot of ATP.
10. Which of following statement is FALSE?
A. An isolate could grow in a nutrient medium without amino acids but grows faster on an
amino-acid-added medium. This statement suggests that amino acids are trace nutrients for this isolate.
B. Defined media are prepared by adding individual "pure" chemicals in known quantities.
C. Growth factors are always organic compounds, including vitamins, amino acids, purines, and pyrimidines.
D. Complex media contain at least one undefined product to be considered complex or undefined. Sai
11. Where does electron transport of cellular respiration happen within the cell of a bacterium? A. Cytoplasm B. Mitochondria C. Plasma membrane D. Nucleus Quiz mùa trước
1. Which of following statement is FALSE?
A. Prokaryotes tend to survive and adapt more rapidly to extreme and dynamic
environmental conditions than eukaryotes
B. A bacterial cell is interpreted as Gram-positive when it form purple insoluble crystal
violet iodine complexes within the cell during the Gram stain.
C. Porins are channels in the outer membranes of gram-negative Bacteria.
D. Smaller prokaryotic cells generally grow faster than larger ones due to a higher surface area to volume ratio.
2. What is the function of endospores?
A. They help bacteria reproduce
B. They increase the ability of bacteria to live in extreme conditions C. They transport toxins D. Al of the above
3. Which type of microscopy below could be used to observe different layers of the cell walls? A. TEM B. bright-field microscopy C. SEM D. phase-contrast microscopy lOMoAR cPSD| 58504431 4. An endotoxin is
A. the toxic portion of the LPS.
B. a toxin originated from archaeal cells.
C. primary attack on the epidermis.
D. a toxin produced within most bacteria cells
5. Compared to Eukaryotes, Bacteria and Archaea have ________ surface-to-volume
ratios, causing ________ nutrient exchange and growth rates. lower / lower lower / higher higher / lower higher / higher
6. In microbiology, Robert Koch was the first person to A. All of the options.
B. develop the tuberculin test.
C. use agar as a solidifying agent in growth media.
D. formulate four postulates for definitively linking a specific microorganism to a specific disease.
7. ________ was the first one to see bacteria while ________ was the first to describe microorganisms
Antoni van Leeuwenhoek / Robert Hooke
8. The lipopolysaccharide (LPS) layer is found ONLY in the cell surface of A. gram-positive Bacteria.
B. gram-negative Bacteria. C. Archaea. D. Eukarya.
9. Which of the following statements is TRUE?
A. Fimbriae are generally shorter and more numerous than flagella.
B. Fimbriae enable cells to stick to surfaces.
C. Pili serve as receptors and facilitate genetic exchange between prokaryotic cells.
D. Fimbriae are usually shorter than flagella and enable cells to adhere to
surfaces, whereas pili are involved in genetic exchange.
10. Which statement below is false?*
A. Smaller prokaryotic cells generally grow faster than larger ones due to a higher surface-area-to-volume ratio.
B. Some membrane proteins are involved in bioenergetic reactions, while others are
involved in membrane transport.
C. Porins are channels in the outer membranes of gram-negative Bacteria.
D. Each of the three major domains has what is known as its own universal ancestor.
11. The first description of a microorganism was of a ________ by ________. A. mold / Robert Hooke
B. yeast / Martinus Beijerinck C. fungus / Robert Koch lOMoAR cPSD| 58504431 D. bacterium / Ferdinand Cohn
… is the one who refuted the theory of spontaneous generation Louis Pasteur.
12. Chemolithotrophy involves A. metabolic autotrophy.
B. oxidation of organic compounds.
C. oxidation of inorganic compounds.
D. reduction of organic compounds.
13. Which of following statement is FALSE?
A. Calcium helps stabilize cell walls in many microorganisms
B. Plates that contain more than one colony type are indicative of a pure culture.
C. Bacterial colonies can be of various shapes and sizes depending on the organism, the culture
conditions, the nutrient supply, and several other physiological parameters.
D. Colonies are visible masses of cells formed from the subsequent division of one or a few cells
14. The class of macromolecules in microorganisms that contributes MOST to biomass is A. carbohydrates. B. lipids. C. DNA. D. proteins.
15. The cytoplasmic membrane could best be described as A. an impermeable barrier.
B. a rigid structure that protects the cell.
C. a passive conduit for intracellular transport.
D. a highly selective permeability barrier.
16. The rising of bread dough is the result of A. biotin production.
B. carbon dioxide produced by fermentation. C. oxidative phosphorylation. D. oxygen being released.
17. Which of the following methods would be used to measure the concentration of bacterial
contamination in processed peanut butter? A. turbidity measurement B. total plate count C. dry weight measurement
D. direct counting of bacteria on a calibrated slide under the microscope
18. What is/are the benefits of pour plate method comparing to spread plate method?
A. Small volumes of cells can be dispensed.
B. Colonies are easier to enumerate on a two- rather than three-dimensional surface.
C. It is possible to enumerate the aerobes, anaerobes and facultative anaerobes.
D. Many cells (psychrophiles and some mesophiles), cannot withstand the warm
temperature of molten agar (~50°C).
19. When cells are metabolically active but not dividing, they are in the A. Lag phase B. Log phase lOMoAR cPSD| 58504431 C. Stationary phase D. Death phase
20. In a chemostat, cells can be maintained at….phase if the concentration of nutrients is controlled. A. death growth. B. stationary growth.
C. log or stationary growth. D. exponential growth.
21. Which of the following statements is FALSE?
A. The lag phase does NOT occur if all the cells in the culture are viable.
B. The rates of exponential growth (in the exponential phase) vary greatly according to
the bacterial species as well as the bioavailable nutrients.
C. Microbial growth is generally described as the increased number of cells rather than
the expanding size of an individual microbial cell.
D. In both lag and stationary phase, there is no net increase or decrease in viable cells.
22. In which phase would you expect to observe the most endospores in a Bacil us cell culture? A. death phase B. lag phase C. log phase
D. log, lag, and death phases would all have roughly the same number of endospores. Quiz 6
1. What is/are the benefits of pour plate method comparing to spread plate method?
A. Small volumes of cells can be dispensed.
B. Colonies are easier to enumerate on a two- rather than three-dimensional surface.
C. It is possible to enumerate the aerobes, anaerobes and facultative anaerobes.
D. Many cells (psychrophiles and some mesophiles), cannot withstand the warm temperature of molten agar (~50°C).
2. Which of the following statement is FALSE?
A. The time between inoculation and the beginning of growth is usually called the lag phase.
B. The number of colonies obtained in a plate count depend on the size of the colonies.
C. The process by which two cells arise from one is known as binary fission.
D. The time interval required for the formation of two cells from one is called the generation time.
3. When cells are metabolically active but not dividing, they are in the ___ lOMoAR cPSD| 58504431 Lag phase Log phase Stationary phase Death phase
4. During the ___ of growth, new cells are more being produced at the same rate as other cells dying Lag phase Log phase Stationary phase Death phase
5. Which of the following methods would be used to measure the concentration of
bacterial contamination in processed peanut butter?
turbidity measurement total plate count dry weight measurement direct
counting of bacteria on a calibrated slide under the microscope
6. If a culture starts with 50 cells, how many cells will be present after three
generations with no cell death? 200 400 800 1600
7. In a chemostat, cells can be maintained at….phase if the concentration of
nutrients is controlled. log or stationary growth. stationary growth. exponential growth. death growth.
8. In which phase would you expect to observe the most endospores in a Bacillus
cell culture? death phase lag phase log phase log, lag, and death phases would all have
roughly the same number of endospores.
9. Which of the following statement is FALSE?
In both lag and stationary phase, there is no net increase or decrease in viable cells.
The rates of exponential growth (in the exponential phase) vary greatly according to the bacterial
species as well as the bioavailable nutrients. lOMoAR cPSD| 58504431
Microbial growth is generally described as the increased number of cells rather than the expanding
size of an individual microbial cell.
The lag phase does NOT occur if all the cells in the culture are viable.
10. How to dilute a sample to be counted 10 times so as to obtain a total volume of 20 ml?* 1 ml sample - 10 ml broth 1 ml sample - 9 ml broth 1 ml sample - 19 ml broth
2 ml sample - 18 ml broth
11. Which of the following statement is FALSE?
An agar plate for counting colonies and maximizing statistical validity should ideally contain 30 to 300 colonies.
For most purposes of studying bacterial isolates, viable counting usually gives accurate information
about the number of active cells present in a culture volume.
Direct microscope counting of stained cells is an accurate method for calculating the exact number of cells in a sample. Sai
When viable cell concentrations are too high to count on an agar medium, it is most common to
use larger sized plates to increase the surface area for counting the colonies. Quiz 7
1. Which of the following statement is FALSE?*
A. Viruses have both an intracellular and an extracellular form.
B. A lytic infection results in the death of the host cell.
C. If the viral host population is small, a
lytic cycle might kill or wipe out the entire host
population and prevent further viral replication.
D. Hepatitis C is a chronic viral disease that
causes slow destruction of tissue and
persistent virions that are not
completely cleared. hepatitis C is more likely
caused by a lytic virus
2. Which structural protein of
coronavirus is responsible for binding of
host cell receptors to facilitate entry of host cell A. Nucleocapsid protein (N) B. Membrane protein (M) C. Spike protein (S) D. Envelope protein (E) lOMoAR cPSD| 58504431 3. Viral replication occurs
A. both intracellularly and extracellularly.
B. either intracellularly or extracellularly,
depending on the virus involved.
C. intracellularly. D. extracellularly. 4. Size of virus is usually in A. centimeters. B. picometers. C. micrometers. D. nanometers.
5. The correct order of steps of virus replication is:
A. Adsorption, Penetration,
Synthesis, Maturation, Release
B. Adsorption, Maturation, Synthesis, Penetration, Release
C. Adsorption, Synthesis, Penetration, Maturation, Release
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D. Penetration, Synthesis, Penetration, Maturation, Release
6. A virus is involved in which of the following processes? A. transduction B. translation C. transformation