The Toughest Trivia Quiz On Microbiology
As we continue without preparation for the Microbiology 130 final exam, I have prepared the next exam in the series to ensure that you are adequately prepared. This quiz is made of 70 questions from different chapters. Give it a shot and see what chances you stand at acing the upcoming exam and is considered one of the toughest trivia quiz on microbiology. Give it a try!
Questions and Answers
- 1.
Which nutritional requirement is “iron (Fe2+)†considered to be a part of?
- A.
The major nutritional elements
- B.
Trace elements
- C.
Organic growth factors
- D.
Vitamins
Correct Answer
B. Trace elementsExplanation
Iron (Fe2+) is considered to be a part of trace elements. Trace elements are essential minerals that are required by the body in very small amounts. Iron is one of these trace elements and is crucial for various bodily functions such as oxygen transport, energy production, and DNA synthesis. Although it is required in small quantities, iron plays a vital role in maintaining overall health and preventing iron deficiency anemia.Rate this question:
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- 2.
Cells that live in high salt environments are called ________.
- A.
Plasmophiles
- B.
Saltophiles
- C.
Tonophiles
- D.
Halophiles
Correct Answer
D. HalophilesExplanation
Halophiles are cells that live in high salt environments. The prefix "halo" refers to salt, and "philes" refers to organisms that thrive in specific conditions. Therefore, halophiles are the correct answer for cells that live in high salt environments.Rate this question:
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- 3.
For a mesophile, the maximum growth temperature would be ____ C.
- A.
30
- B.
37
- C.
45
- D.
60
Correct Answer
C. 45Explanation
A mesophile is an organism that thrives at moderate temperatures, typically between 20-45°C. Therefore, the maximum growth temperature for a mesophile would be 45°C, as temperatures above this range would be too high for optimal growth and could potentially be harmful to the organism.Rate this question:
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- 4.
For a thermophile, the minimum growth temperature would be ____C.
- A.
0
- B.
10
- C.
37
- D.
45
Correct Answer
D. 45Explanation
A thermophile is an organism that thrives in high temperatures. They are adapted to survive and reproduce at temperatures above the normal range for most organisms. Therefore, the minimum growth temperature for a thermophile would be higher than the typical temperature range for other organisms. The option of 45°C is the highest temperature provided, indicating that it is the minimum growth temperature for a thermophile.Rate this question:
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- 5.
Which of these is a good method of preserving microbial cultures?
- A.
Lyophilization
- B.
Heating
- C.
Salting
- D.
Pickling
Correct Answer
A. LyophilizationExplanation
Lyophilization, also known as freeze-drying, is a good method of preserving microbial cultures because it involves freezing the cultures and then removing the water content through sublimation, without causing damage to the cells. This process allows for long-term storage of the cultures while maintaining their viability and characteristics. Heating, salting, and pickling are not suitable methods for preserving microbial cultures as they can potentially kill or alter the microorganisms.Rate this question:
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- 6.
Which of these organisms would not be able to grow in water that has oxygen pumped into it (aerated)?
- A.
Obligate aerobe
- B.
Facultative aerobe
- C.
Obligate anaerobe
- D.
Aerotolerant anaerobe
Correct Answer
C. Obligate anaerobeExplanation
An obligate anaerobe is an organism that cannot survive in the presence of oxygen. It lacks the necessary enzymes to detoxify the reactive oxygen species produced during aerobic respiration. Therefore, it would not be able to grow in water that has oxygen pumped into it.Rate this question:
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- 7.
Mannitol salt agar contains 7.5% salt which only allows the growth of microbes associated with the human body, such as Staphylococcus species. Furthermore, those that are able to ferment mannitol appear yellow in color. What type of medium is Mannitol salt agar?
- A.
Selective
- B.
Differential
- C.
Selective and Differential
- D.
Enrichment
Correct Answer
C. Selective and DifferentialExplanation
Mannitol salt agar is a selective medium because it contains a high concentration of salt (7.5%). This high salt concentration inhibits the growth of most bacteria, making it selective for bacteria that are able to tolerate or grow in the presence of salt, such as Staphylococcus species. Additionally, it is a differential medium because it allows for the differentiation of bacteria based on their ability to ferment mannitol. Bacteria that can ferment mannitol produce acid as a byproduct, which causes the pH indicator in the agar to turn yellow. Therefore, Mannitol salt agar is both selective and differential.Rate this question:
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- 8.
Protein synthesis during lag phase is not occuring because cells are not actively dividing.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
During the lag phase of cell growth, cells are not actively dividing, but this does not mean that protein synthesis is not occurring. In fact, protein synthesis can still take place during this phase as cells prepare for division by producing essential proteins and enzymes. Therefore, the statement that protein synthesis during the lag phase is not occurring because cells are not actively dividing is false.Rate this question:
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- 9.
Which of these microbes is most problematic to humans?
- A.
Psychrophile
- B.
Psychrotroph
- C.
Mesophile
- D.
Thermophile
Correct Answer
C. MesophileExplanation
A mesophile is the most problematic microbe for humans because it thrives in moderate temperatures, which are similar to the human body temperature. This makes it easier for the mesophile to colonize and infect the human body, leading to various diseases and infections. Psychrophiles, psychrotrophs, and thermophiles, on the other hand, prefer extreme temperatures that are either too cold or too hot for human survival, making them less problematic to humans.Rate this question:
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- 10.
Salts and sugars work to preserve foods by creating a ____.
- A.
Lower osmotic pressure
- B.
Hypotonic environment
- C.
Lower pH
- D.
Hypertonic environment
Correct Answer
D. Hypertonic environmentExplanation
Salts and sugars work to preserve foods by creating a hypertonic environment. In a hypertonic environment, the concentration of solutes (salts and sugars) is higher outside the food than inside. This causes water to move out of the food through osmosis, which inhibits the growth of microorganisms that require water to survive. The high concentration of solutes also affects the cellular structure of microorganisms, leading to their dehydration and death. Overall, the hypertonic environment created by salts and sugars helps to preserve the food by inhibiting microbial growth and spoilage.Rate this question:
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- 11.
The large intestines is an environment that lacks any oxygen. Which of the following types of organisms would most likely be found there?
- A.
Obligate aerobe
- B.
Obligate anaerobe
- C.
Microaerophile
- D.
Aerotolerant anaerobe
Correct Answer
D. Aerotolerant anaerobeExplanation
The large intestines is an environment that lacks oxygen, making it an anaerobic environment. Obligate aerobes require oxygen to survive, so they would not be found in the large intestines. Obligate anaerobes cannot survive in the presence of oxygen, so they would also not be found in the large intestines. Microaerophiles require low levels of oxygen to survive, so they would not be found in an environment lacking oxygen. However, aerotolerant anaerobes can survive in the presence or absence of oxygen, making them the most likely type of organism to be found in the large intestines.Rate this question:
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- 12.
At which stage of bacterial growth is cell division the most rapid?
- A.
Lag
- B.
Log
- C.
Stationary
- D.
Death
Correct Answer(s)
A. Lag
B. LogExplanation
During the lag phase, bacteria are adjusting to their new environment and preparing for growth. Once they have adapted, they enter the log phase, where cell division is the most rapid. In this phase, bacteria are actively reproducing and the population size increases exponentially. After the log phase, the growth rate slows down and reaches a plateau in the stationary phase. Finally, in the death phase, the number of dying cells exceeds the number of new cells being produced.Rate this question:
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- 13.
Which of these microbes is most likely to grow at room temperature (25 C)?
- A.
Psychrophile
- B.
Psychrotroph
- C.
Thermophile
- D.
Hyperthermophile
Correct Answer
B. PsychrotrophExplanation
Psychrotrophs are microbes that are capable of growing at low temperatures, typically between 0-25°C. They are able to thrive in refrigerated environments, making them the most likely microbes to grow at room temperature (25°C). Psychrophiles, on the other hand, are microbes that prefer extremely cold temperatures, while thermophiles and hyperthermophiles thrive in high-temperature environments.Rate this question:
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- 14.
____ is used if you want to study obligate anaerobic microbes.
- A.
Enrichment media
- B.
Selective media
- C.
Reducing media
- D.
Differential media
Correct Answer
D. Differential mediaExplanation
Differential media is used if you want to study obligate anaerobic microbes. This type of media contains specific ingredients or indicators that allow for the differentiation of different types of microbes based on their metabolic characteristics or biochemical reactions. It helps to distinguish between different species or strains of microbes by producing visible changes or color variations in the media. This allows researchers to identify and study specific anaerobic microbes of interest.Rate this question:
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- 15.
You want to quantify a culture of motile bacteria. Which method of quantifying would you use if you needed the most accurate information as soon as possible?
- A.
Plate count
- B.
MPN
- C.
Turbidity
- D.
Microscopic count
- E.
Dry weight
Correct Answer
C. TurbidityExplanation
Turbidity is the correct answer because it is a method that provides quick results and is also accurate for quantifying motile bacteria culture. Turbidity measures the cloudiness of a liquid culture, which is directly proportional to the bacterial cell density. By measuring the amount of light that is scattered or absorbed by the culture, turbidity can be used to estimate the bacterial population. This method is advantageous as it is non-destructive and does not require time-consuming steps like plating or microscopic counting. It is a rapid and reliable technique for quantifying bacteria in a culture.Rate this question:
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- 16.
Motility medium is a growth agar medium that contains a low agar concentration. Cells that are motile will be able to grow throughout the medium whereas non-motile cells will only grow where they were inoculated. What type of medium is motility medium.
- A.
Differential
- B.
Selective
- C.
Differential and selective
- D.
Enrichment
Correct Answer
C. Differential and selectiveExplanation
Motility medium is a type of agar medium that contains a low agar concentration. It is both differential and selective. It is differential because it allows for the differentiation of motile and non-motile cells. Motile cells will be able to move and grow throughout the medium, while non-motile cells will only grow in the area where they were initially inoculated. It is also selective because it selects for motile cells by allowing them to move and grow, while inhibiting the growth of non-motile cells in the medium.Rate this question:
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- 17.
Which of these organisms would not be able to grow in water that has oxygen pumped into it (aerated)?
- A.
Obligate aerobe
- B.
Facultative aerobe
- C.
Obligate anaerobe
- D.
Aerotolerant anaerobe
Correct Answer
C. Obligate anaerobeExplanation
Obligate anaerobes are organisms that cannot survive in the presence of oxygen. They lack the necessary enzymes to break down toxic by-products of oxygen metabolism. Therefore, they would not be able to grow in water that has oxygen pumped into it.Rate this question:
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- 18.
Most human pathogens are _________.
- A.
Psychrophiles
- B.
Mesophiles
- C.
Thermophiles
- D.
Psychrotrophs
Correct Answer
B. MesophilesExplanation
Most human pathogens are mesophiles because they thrive and grow best at moderate temperatures, typically around 20-40 degrees Celsius. Mesophiles can adapt to the temperature range found in the human body, making them well-suited to infect and cause diseases in humans. Psychrophiles are cold-loving organisms, thermophiles thrive in high temperatures, and psychrotrophs can grow at low temperatures but also have an optimum growth temperature in the mesophilic range. However, the majority of human pathogens are mesophiles.Rate this question:
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- 19.
Which method of quantifying bacterial numbers would be most effective for measuring the numbers of bacteria in drinking water, when you expect the numbers to be relatively low?
- A.
Filtration
- B.
Plate count
- C.
Direct microscopic count
- D.
Turbidity
Correct Answer
A. FiltrationExplanation
Filtration would be the most effective method for quantifying bacterial numbers in drinking water when expecting relatively low numbers. Filtration involves passing the water sample through a filter that captures the bacteria, which can then be cultured and counted. This method is advantageous because it concentrates the bacteria, making it easier to detect low numbers. Plate count, direct microscopic count, and turbidity may not be as effective in this scenario as they may have limitations in accurately quantifying low bacterial numbers in drinking water.Rate this question:
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- 20.
Which of the following is a limitation of the autoclave?
- A.
Requires a long time to achieve sterilization.
- B.
Cannot inactivate viruses.
- C.
Cannot kill endospores.
- D.
Cannot be used with heat-sensitive materials.
Correct Answer
C. Cannot kill endospores.Explanation
The autoclave is a commonly used device for sterilization, but it has its limitations. One of these limitations is that it cannot kill endospores. Endospores are highly resistant structures produced by certain bacteria that can withstand extreme conditions, including heat and chemicals. The autoclave uses high-pressure steam to kill microorganisms, but it may not be effective against endospores. Therefore, if endospores are present, alternative methods of sterilization may need to be used.Rate this question:
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- 21.
Which of the following treatments does not yield a sterile product?
- A.
Ionizing radiation
- B.
Autoclaving
- C.
0.45 um filtration
- D.
Gamma radiation
Correct Answer
C. 0.45 um filtrationExplanation
The process of 0.45 um filtration does not yield a sterile product because it is not capable of removing all microorganisms from the solution. While it can effectively filter out larger particles and some bacteria, it may not be able to remove smaller microorganisms such as viruses. Therefore, it is not considered a sterilization method but rather a method for reducing the microbial load in a solution.Rate this question:
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- 22.
A microbial culture contains 1 million cells. If it takes 25 minutes to kill all microbes in a culture, the DRT is ______.
- A.
25 minutes
- B.
1 million cells
- C.
Not enough information
Correct Answer
C. Not enough informationExplanation
The DRT (Decimal Reduction Time) is the time required to reduce the number of microorganisms in a culture by one logarithmic cycle or 90%. In this question, we are given the number of cells in the culture (1 million) and the time it takes to kill all microbes (25 minutes). However, we do not have information about the reduction rate or the specific microorganism being targeted. Therefore, we cannot determine the DRT based on the given information.Rate this question:
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- 23.
Which one of the following would be the most likely to spoil a jar of jam in your fridge?
- A.
Eurotium, a mold
- B.
Pseudomonas, a psychrotrophic bacterium
- C.
Thibacillus, an acidophile
- D.
Streptococcus pyogenes, a human pathogen
Correct Answer
A. Eurotium, a moldExplanation
Eurotium is a type of mold that commonly grows on fruits and vegetables, including jam. Mold can spoil a jar of jam by producing enzymes that break down the sugars and other components of the jam, causing it to spoil and develop an off taste or odor. Mold can also produce toxins that can be harmful if consumed. Therefore, Eurotium, being a mold, is the most likely to spoil a jar of jam in the fridge.Rate this question:
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- 24.
Based upon the information provided, which of these disinfectant treatments is more effective, a higher concentration for a shorter time, or a lower concentration for a longer time?
- A.
High concentration, short time.
- B.
Low concentration, long time.
- C.
Equally effective.
Correct Answer
C. Equally effective.Explanation
The question asks which disinfectant treatment is more effective: a higher concentration for a shorter time or a lower concentration for a longer time. The answer is that they are equally effective. This means that both treatments have the same level of effectiveness in killing or reducing the number of microorganisms. The concentration and duration of the treatment do not significantly impact its effectiveness.Rate this question:
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- 25.
In the disk-diffusion method, a ____ zone of inhibition around a filter soaked with a chemical indicates that the test bacteria is resistant to the chemical.
- A.
Small
- B.
Large
- C.
Colored
- D.
Clear
Correct Answer
A. SmallExplanation
A small zone of inhibition around a filter soaked with a chemical in the disk-diffusion method indicates that the test bacteria is resistant to the chemical. This is because a small zone of inhibition suggests that the chemical was not effective in inhibiting the growth of the bacteria, indicating resistance. A larger zone of inhibition would indicate that the chemical was able to effectively inhibit the growth of the bacteria, suggesting susceptibility. Since the question asks for the zone of inhibition that indicates resistance, the correct answer is "small".Rate this question:
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- 26.
Which of the following is not used to preserve foods?
- A.
Desiccation
- B.
Ionizing radiation
- C.
Microwaves
- D.
Osmotic pressure
Correct Answer
C. MicrowavesExplanation
Microwaves are not commonly used to preserve foods. While microwaves can heat and cook food, they do not have the same preserving effect as other methods like desiccation, ionizing radiation, or osmotic pressure. Desiccation involves removing moisture from food, which inhibits the growth of bacteria and molds. Ionizing radiation can kill microorganisms and extend the shelf life of certain foods. Osmotic pressure involves using high concentrations of salt or sugar to draw out moisture from food, preventing the growth of bacteria. Microwaves, on the other hand, primarily heat food and do not have the same preserving properties.Rate this question:
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- 27.
Which of these are most likely to survive in a hypertonic environment?
- A.
Bacteria
- B.
Molds
- C.
Viruses
- D.
Algae
Correct Answer
B. MoldsExplanation
Molds are most likely to survive in a hypertonic environment because they have the ability to tolerate high concentrations of solutes. In a hypertonic environment, where there is a higher concentration of solutes outside the cell than inside, water tends to move out of the cell, causing dehydration and potential cell death. Molds, however, have adapted mechanisms to withstand this osmotic stress, such as producing osmolytes or adjusting their cell membrane permeability. This allows them to maintain their cellular integrity and survive in hypertonic conditions.Rate this question:
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- 28.
Pseudomonas species are unusually resistant to antimicrobial treatment due to the presence of _________.
- A.
Porins
- B.
A plasma membrane
- C.
An extremely hard cell wall
- D.
Antibiotics
Correct Answer
A. PorinsExplanation
Pseudomonas species are unusually resistant to antimicrobial treatment due to the presence of porins. Porins are proteins found in the outer membrane of the bacterial cell wall that act as channels, allowing the passage of certain molecules, including antibiotics, into the cell. However, in Pseudomonas species, the porins are less permeable, limiting the entry of antibiotics and making them more resistant to treatment.Rate this question:
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- 29.
Which of these have a direct effect on antimicrobial treatments?
- A.
Climate
- B.
Mass of surface being treated.
- C.
Number of microbes present.
- D.
Area of surface being treated.
Correct Answer
C. Number of microbes present.Explanation
The number of microbes present directly affects antimicrobial treatments because the efficacy of these treatments depends on the concentration of microbes. A higher number of microbes may require a higher dosage or longer duration of treatment to effectively eliminate them. Conversely, a lower number of microbes may require a lower dosage or shorter duration of treatment. Therefore, the number of microbes present is a crucial factor in determining the effectiveness of antimicrobial treatments.Rate this question:
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- 30.
All media needs to be free of microbes, so you need to ____ media before you use it.
- A.
Sterilize
- B.
Disinfect
- C.
Sanitize
- D.
Degerm
Correct Answer
A. SterilizeExplanation
To ensure that media is free of microbes, it needs to undergo a process that eliminates all microorganisms. This process is known as sterilization. Sterilization is the most effective method for killing or removing all forms of microbial life, including bacteria, viruses, and fungi. It is necessary to sterilize media before using it to prevent the growth and spread of harmful microorganisms, ensuring the safety and integrity of the media for its intended purpose. Disinfecting, sanitizing, and degerming are other methods that reduce the number of microorganisms but do not necessarily eliminate all of them.Rate this question:
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- 31.
Bacterial death will result from damage to which of the following structures?
- A.
Plasma membrane
- B.
Proteins
- C.
Nucleic acids
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
All of the above. Bacterial death can result from damage to the plasma membrane, proteins, and nucleic acids. The plasma membrane is responsible for maintaining the integrity of the cell and regulating the movement of molecules in and out of the cell. Damage to the plasma membrane can disrupt these functions and ultimately lead to bacterial death. Proteins are essential for various cellular processes, and damage to proteins can interfere with their normal functions, causing cell death. Nucleic acids, specifically DNA, contain the genetic information of the bacterium, and damage to the nucleic acids can result in mutations or loss of essential genetic material, leading to cell death.Rate this question:
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- 32.
Salts and sugars work to preserve foods by creating a ____.
- A.
Lower osmotic pressure
- B.
Hypotonic environment
- C.
Lower pH
- D.
Hypertonic environment
Correct Answer
D. Hypertonic environmentExplanation
Salts and sugars work to preserve foods by creating a hypertonic environment. In a hypertonic environment, the concentration of solutes outside the cells is higher than inside the cells. This causes water to move out of the cells through osmosis, which inhibits the growth of microorganisms and slows down the spoilage of the food. The high concentration of salts and sugars in the environment creates an unfavorable condition for microbial growth, thus preserving the food for longer periods.Rate this question:
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- 33.
A bacterial culture was treated at 55 C. Treating the culture for 5 and 10 minutes did not effectively kill the bacteria, but treatment for 15 minutes killed all the cells. What is the TDT?
- A.
5 mins
- B.
10 mins
- C.
15 mins
- D.
More than 15 mins
Correct Answer
C. 15 minsExplanation
The thermal death time (TDT) is the minimum time required to kill all the bacteria in a culture at a specific temperature. In this case, the bacteria were not effectively killed after 5 and 10 minutes of treatment at 55°C, but all the cells were killed after 15 minutes. Therefore, the TDT for this culture at 55°C is 15 minutes.Rate this question:
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- 34.
A microbial culture contains 1 million cells. If it takes 25 minutes to kill all microbes in a culture, the TDT is ______.
- A.
25 minutes
- B.
1 million cells
- C.
Not enough information
Correct Answer
A. 25 minutesExplanation
The TDT (Time to Death) is the time it takes to kill all the microbes in a culture. In this case, we are given that there are 1 million cells in the culture and it takes 25 minutes to kill them all. Therefore, the TDT is 25 minutes.Rate this question:
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- 35.
Commercial sterilization involves heat treatment to destroy ______ of bacteria.
- A.
The plasma membrane
- B.
Peptidoglycan
- C.
Endospores
- D.
The outer membrane
Correct Answer
C. EndosporesExplanation
Commercial sterilization involves heat treatment to destroy endospores of bacteria. Endospores are a dormant, highly resistant form of bacteria that can survive extreme conditions. They have a tough outer layer that protects them from heat, chemicals, and other sterilization methods. By targeting and destroying endospores, commercial sterilization ensures that all viable forms of bacteria are eliminated, reducing the risk of contamination and ensuring the safety and quality of the sterilized product.Rate this question:
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- 36.
TRNA molecules serve as a link between ______.
- A.
DNA and mRNA
- B.
Codons and anticodons
- C.
Codons and amino acids
- D.
MRNA and rRNA
Correct Answer
C. Codons and amino acidsExplanation
tRNA molecules serve as a link between codons and amino acids. Codons are sequences of three nucleotides on mRNA that correspond to specific amino acids. tRNA molecules have an anticodon region that pairs with the codon on mRNA, and they also carry the corresponding amino acid. This allows tRNA to bring the correct amino acid to the ribosome during protein synthesis, ensuring that the correct sequence of amino acids is incorporated into the growing polypeptide chain.Rate this question:
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- 37.
A gene is best defined as ______.
- A.
A segment of DNA
- B.
Three nucleotides that code for an amino acid
- C.
A segment of DNA that codes for a functional product
- D.
A segment of RNA that codes for a functional product
Correct Answer
C. A segment of DNA that codes for a functional productExplanation
A gene is best defined as a segment of DNA that codes for a functional product. Genes are the basic units of heredity and contain the instructions for building and maintaining an organism. They are composed of specific sequences of nucleotides, which are the building blocks of DNA. These nucleotide sequences provide the information necessary for the production of functional products, such as proteins or RNA molecules, which play essential roles in various biological processes.Rate this question:
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- 38.
The LacI repressor of the lac operon binds to the ______ when lactose is not present.
- A.
Promoter
- B.
Operator
- C.
Inducer
- D.
Regulator
Correct Answer
B. OperatorExplanation
The LacI repressor of the lac operon binds to the operator when lactose is not present. The operator is a DNA sequence located near the promoter region of the lac operon. When lactose is absent, the LacI repressor binds to the operator, preventing RNA polymerase from binding to the promoter and initiating transcription. This helps regulate the expression of the lac operon by preventing unnecessary production of lactose-metabolizing enzymes when lactose is not available.Rate this question:
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- 39.
Which of these anticodons are found on the tRNA molecule for the amino acid methionine?
- A.
UAC
- B.
AUG
- C.
ATG
- D.
CUG
Correct Answer
A. UACExplanation
The anticodon UAC is found on the tRNA molecule for the amino acid methionine. Anticodons are sequences of three nucleotides on tRNA that complement the codons on mRNA during protein synthesis. The codon AUG on mRNA codes for methionine, and its complementary anticodon on tRNA is UAC. Therefore, UAC is the correct anticodon for methionine.Rate this question:
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- 40.
Which of these is involved in translation?
- A.
DNA polymerase
- B.
RNA polymerase
- C.
DNA
- D.
MRNA
Correct Answer
D. MRNAExplanation
mRNA is involved in translation. Translation is the process by which the genetic information carried by mRNA is used to synthesize proteins. During translation, the mRNA molecule is read by ribosomes, which assemble amino acids in the correct sequence to form a protein. DNA polymerase and RNA polymerase are not directly involved in translation. DNA polymerase is responsible for DNA replication, while RNA polymerase is involved in transcription, the process of synthesizing mRNA from a DNA template. DNA is the genetic material that carries the instructions for protein synthesis, but it is not directly involved in the process of translation.Rate this question:
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- 41.
The information carried by DNA is used to create a _____ which then moves to the ribosome for protein synthesis.
- A.
TRNA
- B.
RRNA
- C.
MRNA
- D.
DRNA
Correct Answer
C. MRNAExplanation
mRNA, or messenger RNA, carries the genetic information from DNA to the ribosome for protein synthesis. It is transcribed from DNA and serves as a template for protein production. mRNA is responsible for carrying the genetic code from the nucleus to the cytoplasm, where it is read by the ribosome to assemble the correct sequence of amino acids into a protein. Therefore, mRNA is the correct answer in this context.Rate this question:
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- 42.
Which of the following properties are exclusive (unique) to mRNA?
- A.
Combines with specific proteins to form ribosomes.
- B.
Carries information from DNA for synthesis of a protein.
- C.
Molecules contain an anticodon.
- D.
Contains the nucleotide thymine.
Correct Answer
B. Carries information from DNA for synthesis of a protein.Explanation
mRNA, or messenger RNA, is the molecule that carries genetic information from DNA to the ribosomes, where it is used as a template for protein synthesis. This process is known as transcription and is exclusive to mRNA. The other properties listed, such as combining with specific proteins to form ribosomes, containing an anticodon, and containing the nucleotide thymine, are not exclusive to mRNA and can also be found in other types of RNA molecules.Rate this question:
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- 43.
E. coli can metabolize both glucose and lactose. If grown in the presence of both sugars, E. coli will metabolize glucose first. This is referred to as _______.
- A.
Catabolite repression
- B.
Catabolite induction
- C.
Inducible expression
- D.
Repressible expression
Correct Answer
A. Catabolite repressionExplanation
Catabolite repression refers to the phenomenon where E. coli preferentially metabolizes glucose over other sugars when both are present. This is because glucose is a more efficient energy source for the bacteria. The presence of glucose inhibits the expression of genes involved in the metabolism of other sugars, such as lactose. This repression allows E. coli to efficiently utilize glucose before turning to alternative carbon sources.Rate this question:
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- 44.
The enzyme responsible for transcription is
- A.
DNA polymerase
- B.
RNA polymerase
- C.
Ribosomes
- D.
Transposase
Correct Answer
B. RNA polymeraseExplanation
RNA polymerase is responsible for transcription, which is the process of synthesizing RNA molecules from DNA templates. DNA polymerase, on the other hand, is responsible for DNA replication. Ribosomes are involved in translation, the process of protein synthesis. Transposase is an enzyme that catalyzes the movement of transposable elements within a genome. Therefore, the correct answer is RNA polymerase as it specifically carries out the transcription process.Rate this question:
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- 45.
Which of the following properties are exclusive (unique) to rRNA?
- A.
Combines with specific proteins to form ribosomes.
- B.
Carries information from DNA for synthesis of a protein.
- C.
Molecules contain an anticodon.
- D.
Contains the nucleotide thymine.
Correct Answer
A. Combines with specific proteins to form ribosomes.Explanation
rRNA is the only property listed that is exclusive to rRNA. While mRNA carries information from DNA for protein synthesis and tRNA contains an anticodon, rRNA is the only one that combines with specific proteins to form ribosomes. The presence of thymine in a molecule is not exclusive to rRNA, as DNA also contains thymine.Rate this question:
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- 46.
The three nucleotide units in an mRNA molecule that code for amino acids are called ______.
- A.
Proteins
- B.
Genes
- C.
RRNA
- D.
Codons
Correct Answer
D. CodonsExplanation
Codons are the three nucleotide units in an mRNA molecule that code for amino acids. They act as the instructions for the synthesis of proteins during the process of translation. Each codon corresponds to a specific amino acid, allowing the correct sequence of amino acids to be determined and the protein to be properly synthesized. Therefore, codons play a crucial role in the translation of genetic information into functional proteins.Rate this question:
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- 47.
Which of the following properties are exclusive (unique) to tRNA?
- A.
Combines with specific proteins to form ribosomes.
- B.
Carries information from DNA for synthesis of a protein.
- C.
Molecules contain an anticodon.
- D.
Contains the nucleotide thymine.
Correct Answer
C. Molecules contain an anticodon.Explanation
tRNA molecules contain an anticodon, which is a sequence of three nucleotides that is complementary to a specific codon on mRNA during protein synthesis. This is a unique property of tRNA because no other molecule or structure in the given options is specifically responsible for carrying an anticodon. The other properties mentioned, such as combining with specific proteins to form ribosomes and carrying information from DNA for protein synthesis, are not exclusive to tRNA as other molecules and structures also play a role in these processes. Additionally, tRNA does not contain the nucleotide thymine, as it is replaced by uracil in RNA molecules.Rate this question:
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- 48.
A sequence of DNA nucleotides which provides genetic information for a functional product is a ______.
- A.
Chromosome
- B.
Plasmid
- C.
Gene
- D.
Base pair
Correct Answer
C. GeneExplanation
A gene is a sequence of DNA nucleotides that carries the instructions for creating a functional product, such as a protein or RNA molecule. It provides the genetic information necessary for the development, functioning, and traits of an organism. Chromosomes are structures that contain genes, while plasmids are small, circular DNA molecules that can be found in some bacteria. Base pairs are the building blocks of DNA, consisting of two nucleotides bonded together. Therefore, the correct answer is gene.Rate this question:
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- 49.
Which enzyme is responsible for unzipping the double stranded DNA?
- A.
DNA polymerase
- B.
DNA helicase
- C.
DNA ligase
- D.
DNA zippase
Correct Answer
B. DNA helicaseExplanation
DNA helicase is responsible for unzipping the double stranded DNA. It is an enzyme that unwinds and separates the two strands of the DNA molecule during DNA replication or transcription. DNA helicase uses ATP energy to break the hydrogen bonds between the complementary base pairs, allowing the DNA strands to separate and expose the template strand for replication or transcription. This process is essential for DNA replication and other DNA-related processes in the cell. DNA polymerase, DNA ligase, and DNA zippase are not involved in the unzipping of the double stranded DNA.Rate this question:
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- 50.
Phosphoglycerate kinase (PGK), an enzyme involved in glycolysis, is constitutively expressed. Which statement is true about the PGK gene?
- A.
PGK is expressed when glucose is present.
- B.
PGK is always expressed.
- C.
The expression of PGK is repressed when glucose is present.
- D.
You cannot predict the pattern of PGK expression.
Correct Answer
B. PGK is always expressed.Explanation
The correct answer is "PGK is always expressed." This means that the PGK gene is constantly active and producing the PGK enzyme regardless of the presence or absence of glucose. It is constitutively expressed, meaning that its expression is not regulated by external factors such as glucose levels.Rate this question:
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