Growth and Nutrition of Bacteria

Q1: Some organisms can use reduced inorganic compounds as electron donors and are termed as

A lithotrophs

B phototrophs

C chemotrophs

D photo-organotrophs

ANS:A - lithotrophs

No answer description is available. 

Q2: Generation time is

A time required for the population to double

B time required for the initial adjustment

C obtained by expression t/n, where t = time interval, n = number of generation

D both (a) and (c)

ANS:D - both (a) and (c)

No answer description is available. 

Q3: The average size of cells during the exponential phase of growth is

A greater than the lag phase

B lesser than the lag phase

C equal to the lag phase

D none of these

ANS:B - lesser than the lag phase

No answer description is available. 

Q4: The term aerotolerant anaerobe refers to an organism that

A doesn't use oxygen but can grow in the presence of oxygen

B is killed by oxygen

C requires less oxygen than is present in air

D prefers to grow without oxygen

ANS:A - doesn't use oxygen but can grow in the presence of oxygen

No answer description is available. 

Q5: Pseudomonas pseudoflava can grow as

A chemo-lithotrophs

B chemo-organotrophs

C both (a) and (b)

D none of these

ANS:C - both (a) and (b)

No answer description is available.

Q6: A microbe, which grows at temperatures above 95° C is most likely to be

A an archaean

B a fungus

C a protozoan

D none of these

ANS:A - an archaean

No answer description is available. 

Q7: The generation time of a culture that produces two generations per hour is

A greater than that produces three generations per hour

B lesser than that produces three generations per hour

C equal to that produces three generations per hour

D none of the above

ANS:A - greater than that produces three generations per hour

No answer description is available. 

Q8: The equation used to obtain bacterial population by binary fission is

A N = No2n

B log N/No = (0.3010) n

C log(N/No) = nlog 2

D All of these

ANS:D - All of these

Please explain the answer.

Q9: Nutrient content and biological structures are considered as

A implicit factor for microbial growth

B intrinsic factor for microbial growth

C processing factor

D none of the above

ANS:B - intrinsic factor for microbial growth

No answer description is available. 

Q10: An organism is completely dependent on atmospheric O2 for growth. This organism is

A osmotolerant

B acidophile

C facultative anaerobe

D obligate aerobe

ANS:D - obligate aerobe

No answer description is available. 

Q11: A synergistic effect is observed when

A one organism removes an inhibitory substance for another

B one organism produces a growth factor utilized by another

C microbial alteration of pH, aw, Eh favours the growth of another

D all of the above

ANS:D - all of the above

No answer description is available. 

Q12: All organisms require at least small amounts of carbondioxide, However, some can use CO2 as their sole source of carbon. Such organisms are termed as

A autotrophs

B phototrophs

C chemotrophs

D photo-organotrophs

ANS:A - autotrophs

No answer description is available. 

Q13: Which of the following organisms typically get their carbon for biosynthesis from organic compounds?

A Aerobic, glucose-respiring bacteria (aerobic respiration)

B Ammonia-oxidizing bacteria (chemolithotrophic bacteria)

C Photosynthetic cyanobacteria (phototrophic metabolism)

D None of the above

ANS:A - Aerobic, glucose-respiring bacteria (aerobic respiration)

No answer description is available. 

Q14: What are the extrinsic factors for the microbial growth?

A humidity

B storage temperature

C composition of gas phase

D all of these

ANS:A - humidity

No answer description is available. 

Q15: The straightforward method of binary fission explains how bacteria

A grow in nutrient agar

B evolve

C move

D reproduce

ANS:D - reproduce

No answer description is available. 

Q16: Exponential phase of growth curve of bacteria is of limited duration because of

A rise in cell density

B accumulation of toxic metabolites

C exhaustion of nutrients

D all of these

ANS:D - all of these

No answer description is available. 

Q17: A culture broth tube was very turbid at the surface but clear throughout the rest of the tube indicating that the

A organism are aerobes

B organism should be grown in an anaerobic chamber

C organism cannot produce superoxide dismutase and/or catalase

D organism cannot tolerate oxygen

ANS:B - organism should be grown in an anaerobic chamber

No answer description is available. 

Q18: The term facultative anaerobe refers to an organism that

A doesn't use oxygen but tolerates it

B is killed by oxygen

C uses oxygen when present or grows without oxygen when absent

D requires less oxygen than is present in air

ANS:C - uses oxygen when present or grows without oxygen when absent

No answer description is available. 

Q19: In the exponential phase, the cells and cell mass

A first increases then decreases

B decreases

C are constant

D double at a constant rate

ANS:D - double at a constant rate


No answer description is available. 

Q20: A spore differs from an actively replicating bacterium in that the spore

A is produced during a process involving asymmetric division

B is able to withstand more extreme conditions than the replicating cell

C is metabolically inactive

D all of the above

ANS:D - all of the above

No answer description is available. 

Q21: Which of the following is the suitable temperature range for mesophiles?

A 20-30°C

B 25-40°C

C >40°C

D None of these

ANS:B - 25-40°C

No answer description is available. 

Q22: During exponential growth, the growth rate is

A number of generations per unit time

B reciprocal of generation time

C both (a) and (b)

D none of these

ANS:B - reciprocal of generation time

No answer description is available. 

Q23: The organism which grows best above 45°C are called

A psychrophilic

B mesosphilic

C thermophilic

D any of these

ANS:C - thermophilic

No answer description is available. 

Q24: Generation time of Escherichia coli is

A 20 minutes

B 20 hours

C 20 days

D 200 hours

ANS:A - 20 minutes

No answer description is available. 

Q25: The cell reproduction in bacteria may occur by

A binary fission

B budding

C fragmentation

D all of these

ANS:C - fragmentation

No answer description is available. 

Q26: Organisms, using organic compounds as electron donors are called

A lithotrophs

B phototrophs

C chemotrophs

D organotrophs

ANS:D - organotrophs

No answer description is available. 

Q27: The period between inoculation of bacteria in a culture medium and beginning of multiplication is known as

A stationary phase

B log phase

C lag phase

D decline phase

ANS:C - lag phase

No answer description is available. 

Q28: Bacteria of genusNitrosomonas use __________ as their electron source.

A ammonia

B H2S

C succinate

D light

ANS:A - ammonia

No answer description is available.

Q29: The combination of low levels of NaCl, NaNO3 (sodium nitrate), and slightly acid pH can prevent multiplication and toxin formation of

A Salmonella

B S. aureus

C botulinum

D all of these

ANS:D - all of these

No answer description is available. 

Q30: An organism has an optimal growth rate when the hydrogen ion concentration is very high. This organism is

A osmotolerant

B acidophile

C neutrophile

D aerotolerant anaerobe

ANS:B - acidophile

The level of alkalinity and acidity is determined by Number of Hydrogen or Hydroxide Concentrations. Thus, The increase of Hydrogen concentration leads to Increase the Acidity.

Q31: The term obligate anaerobe refers to an organism that

A doesn't use oxygen but tolerates it

B is killed by oxygen

C uses oxygen when present or grows without oxygen when oxygen is absent

D prefers to grow without oxygen

ANS:B - is killed by oxygen

No answer description is available. 

Q32: The growth is normally expressed as __________ in turbidimetric measurement

A cells per ml

B cfu/ml

C optical density

D mg N2 /ml

ANS:C - optical density

No answer description is available. 

Q33: The total biomass of an organism will be determined by the nutrient present in the lowest concentration relative to the organism's requirements is a statement of

A Liebig's law of the minimum

B Shelford's law of tolerance

C quorum sensing

D Heisenberg's principle of uncertainty

ANS:A - Liebig's law of the minimum

No answer description is available. 

Q34: What is the primary source of food for marine life?

A Phytoplankton

B Zooplankton

C Sea weed

D Grass

ANS:A - Phytoplankton

No answer description is available. 

Q35: Starvation proteins are produced by a culture during which of the following segments of the growth curve?

A Lag phase

B Exponential phase

C Stationary phase

D Death phase

ANS:C - Stationary phase

No answer description is available. 

Q36: Bacteria and fungi multiply best

A below 16°C

B between 16-38°C

C above 38°C

D none of these

ANS:B - between 16-38°C

No answer description is available. 

Q37: Which of the following is not the characteristic of a growth curve?

A Shows development of microbial population under relatively stable environmental conditions

B Plotted with logarithmic numbers

C Graphs numbers of microbes versus time

D Each growth curve consists of four distinct phases

ANS:D - Each growth curve consists of four distinct phases

No answer description is available. 

Q38: Which of the following procedures uses a photocell to measure absorbance of a culture to regulate the flow of culture media?

A Coulter Counter

B Hemostat

C Petroff-Hausser chamber

D Trubidostat

ANS:D - Trubidostat

No answer description is available.

Q39: Which of the following is used to grow bacterial cultures continuously?

A Chemostat

B Coulter Counter

C Hemostat

D Petroff-Hausser chamber

ANS:A - Chemostat

No answer description is available. 

Q40: The microorganisms that grow best in a low-oxygen environment is called a (n)

A aerobe

B anaerobe

C facultative

D microaerophile

ANS:D - microaerophile

No answer description is available. 

Q41: Implicit factors

A depend on developing microflora

B can be synergistic

C both (a) and (b)

D none of the above

ANS:C - both (a) and (b)

No answer description is available. 

Q42: Autotrophic bacteria are those which

A make their own food

B form a long chain glycocalyx

C are highly susceptible to penicillin

D produce a blue-green pigment

ANS:A - make their own food

No answer description is available. 

Q43: An organism that expends energy to grow in a habitat with a low water activity in order to maintain internal solute concentrations to retain water is

A osmotolerant

B acidophile

C aerotolerant anaerobe

D alkalophile

ANS:A - osmotolerant

No answer description is available. 

Q44: Antimicrobial constituents for the microbial growth in foods are

A intrinsic factor

B extrinsic factor

C both (a) and (b)

D none of these

ANS:A - intrinsic factor

No answer description is available. 

Q45: Lag phase is also known as

A period of initial adjustment

B transitional period

C generation time

D none of these

ANS:A - period of initial adjustment

No answer description is available. 

Q46: A culture broth tube was very turbid at the bottom of the tube but clear at the top of the tube indicating that the

A broth is sterile

B organism can tolerate oxygen

C organism cannot produce superoxide dismutase and/or catalase

D organism should be grown in an anaerobic chamber

ANS:C - organism cannot produce superoxide dismutase and/or catalase

No answer description is available. 

Q47: Quantitative measurement of bacterial growth can be carried out by measuring

A cell count

B cell mass

C cell activity

D all of these

ANS:D - all of these

No answer description is available. 

Q48: Which of the following organisms typically get their carbon for biosynthesis from carbon dioxide?

A Glucose-fermenting bacteria (fermentation)

B Anaerobic, glucose-respiring bacteria (anaerobic respiration)

C Aerobic, glucose-respiring bacteria (aerobic respiration)

D Ammonia-oxidizing bacteria (chemolithotrophic bacteria)

ANS:D - Ammonia-oxidizing bacteria (chemolithotrophic bacteria)

No answer description is available.

Q49: The ability of Vibrio fischeri to produce bioluminescence chemicals only when a certain population density has been reached is an example of

A Liebig's law of the minimum

B Shelford's law of tolerance

C quorum sensing

D Heisenberg's principle of uncertainty

ANS:C - quorum sensing

No answer description is available. 

Q50: Organisms such as lactobacilli that have elaborate requirements for specific nutrients i.e. vitamins and other growth promoting substances, are generally called as

A fastidious hetrotrophs

B chemo-lithotrophs

C chemotrophs

D photo-organotrophs

ANS:A - fastidious hetrotrophs

No answer description is available. 

Q51: Which of the following has more tolerance for acidic pH (lower pH)?

A Yeast and moulds

B Bacteria

C E. coli

D None of these

ANS:A - Yeast and moulds

No answer description is available. 

Q52: Microaerophilic bacteria are those which require

A 21 % oxygen for growth

B low levels of oxygen for growth (lesser than O2 present in atmosphere)

C oxygen for activation of enzymes

D none of the above

ANS:B - low levels of oxygen for growth (lesser than O2 present in atmosphere)

No answer description is available. Let's discuss.

Q53: Postgates assay technique is useful in determining if a cell is viable even though it is

A incapable of cell division

B too small to see

C an obligate aerobe

D a thermophile

ANS:A - incapable of cell division

No answer description is available.

Q54: The fragmentation occurs in

A Streptomyces species

B Nocardia species

C Bacillus subtilis

D None of these

ANS:B - Nocardia species

No answer description is available. 

Q55: The reproduction by budding occur in

A Rhodopseudomonas acidophila

B Hyphomicrobium vulgare

C Bacillus subtilis

D Both (a) and (b)

ANS:D - Both (a) and (b)

No answer description is available. Let's discuss.

Q56: The organism which obtain their energy from chemicals are designated as

A prototrophs

B chemotrophs

C organotrophs

D autotrophs

ANS:B - chemotrophs

No answer description is available. 



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