Microbiology Unit II: Factors Affecting Microbe Growth

1.

These bacterium prefer cooler temperatures (below 15* C)

Explanation
Psychrophiles are a type of bacteria that thrive in cold temperatures, specifically below 15°C. They have adapted to survive in these extreme conditions by developing unique physiological and biochemical mechanisms. These bacteria are able to maintain membrane fluidity and enzymatic activity at low temperatures, allowing them to carry out essential metabolic processes. This preference for cooler temperatures sets psychrophiles apart from other types of bacteria that are unable to survive or function optimally in such cold environments.

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2.

Psycrophiles prefer what temperature range?

Explanation
Psychrophiles prefer temperatures below 15C. These are microorganisms that thrive in cold environments such as polar regions and deep ocean waters. They have adapted to survive and even thrive in extremely low temperatures, which would be unsuitable for most other organisms. Psychrophiles have specific adaptations in their cellular structure and metabolism that allow them to function at these cold temperatures. They have enzymes that are active at low temperatures and can still carry out essential biological processes. This preference for cold temperatures is what sets psychrophiles apart from other organisms that prefer warmer environments.

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3.

Do psycrophiles live in humans?

A.

Yes
B.

No

Correct Answer
B. No

Explanation
Psycrophiles are microorganisms that thrive in extremely cold temperatures, such as in polar regions or deep-sea environments. They are not known to live in humans. Human body temperature is much higher than the temperatures at which psycrophiles can survive, making it an inhospitable environment for them. Therefore, the correct answer is "No."

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4.

Mesophiles prefer what temperature range?

Correct Answer
25C to 40C

Explanation
Mesophiles are organisms that thrive in moderate temperature conditions. They prefer a temperature range between 25°C to 40°C. This range is considered optimal for their growth and metabolic activities. Temperatures below this range may be too cold for their survival, while temperatures above this range may be too hot and may denature their proteins. Therefore, mesophiles are adapted to and prefer the moderate temperature range of 25°C to 40°C.

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5.

These bacterium live in humans as both pathogens and non pathogens.

Correct Answer
Mesophiles

Explanation
Mesophiles are a type of microorganisms that thrive in moderate temperature conditions, typically between 20 to 45 degrees Celsius. They are capable of living in humans as both pathogens (causing diseases) and non-pathogens (not causing diseases). These organisms are well adapted to the temperature range found in the human body, making them able to survive and potentially cause infections or diseases in humans.

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6.

Most resturaunts and food industries are concerned about these bacterium because they live both in room and body temperate conditions.

Correct Answer
Mesophiles

Explanation
Restaurants and food industries are concerned about mesophiles because these bacteria can thrive in both room temperature and body temperature conditions. This means that they can easily contaminate food and cause spoilage or foodborne illnesses. Mesophiles are a type of bacteria that prefer moderate temperatures, making them a common concern in the food industry where proper food handling and storage is crucial to prevent bacterial growth and maintain food safety.

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7.

Thermophiles prefer which temperature range?

Correct Answer
50C to 60C

Explanation
Thermophiles are organisms that thrive in high-temperature environments. They are adapted to withstand and even require temperatures ranging from 50°C to 60°C for their optimal growth and survival. These extreme temperatures are necessary for their metabolic processes and enzyme activity. Outside of this temperature range, thermophiles may struggle to function properly or may even be unable to survive.

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8.

Thermophiles are found where?

Correct Answer
Compost piles and hot springs

Explanation
Thermophiles are microorganisms that thrive in extremely high temperatures. They are found in environments such as compost piles and hot springs, where the temperatures can reach levels that would be inhospitable for most other organisms. These organisms have adapted to withstand and even thrive in these extreme conditions, making them well-suited for survival in such environments.

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9.

Do thermophiles live in humans?

A.

Yes
B.

No

Correct Answer
B. No

Explanation
Thermophiles are microorganisms that thrive in extremely high temperatures, usually above 45°C. They are commonly found in hot springs, hydrothermal vents, and volcanic areas. Humans have a relatively stable body temperature of around 37°C, which is much lower than the temperatures preferred by thermophiles. Therefore, thermophiles do not live in humans.

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10.

Which of the following do NOT live in humans?

A.

Psycrophiles
B.

Mesophiles
C.

Thermophiles

Correct Answer(s)
A. PsycropHiles
C. ThermopHiles

Explanation
Psycrophiles and thermophiles are both types of extremophiles, which are organisms that can survive and thrive in extreme temperatures. Psycrophiles are cold-loving organisms that can live in temperatures close to freezing or even below freezing, while thermophiles are heat-loving organisms that can survive in very high temperatures, such as hot springs or deep-sea hydrothermal vents. Humans, on the other hand, are mesophiles, which means they prefer moderate temperatures and cannot survive in extreme cold or extreme heat. Therefore, psycrophiles and thermophiles do not live in humans.

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11.

Most bacteria will survive in a neutral pH of about what?

Correct Answer(s)
6.5 to 7.5

Explanation
Most bacteria are able to survive in a neutral pH range of 6.5 to 7.5. This is because the enzymes and proteins that bacteria rely on for their survival function optimally in this pH range. A neutral pH provides a balanced environment for bacterial growth and metabolism, allowing them to carry out essential processes such as nutrient uptake and waste removal efficiently. Deviations from this pH range can disrupt bacterial homeostasis and hinder their survival and growth.

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12.

In relation to bacteria, why does vinegar never go "bad"?

Correct Answer(s)
Bacteria cannot survive such acidic conditions

Explanation
Vinegar has a high acidity level, which creates an environment that is inhospitable for bacteria to survive. The low pH of vinegar inhibits the growth and reproduction of bacteria, preventing them from thriving and causing the vinegar to spoil. The acidic conditions of vinegar create an unfavorable environment for bacterial growth, ensuring that it does not go "bad".

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13.

What form of organism can tolerate more acidic conditions than bacterium?

Correct Answer(s)
Fungi

Explanation
Fungi can tolerate more acidic conditions than bacteria. This is because fungi have the ability to adjust their internal pH levels to match the external environment. They can secrete enzymes that help them break down complex molecules in acidic environments, allowing them to survive and thrive in acidic conditions. Bacteria, on the other hand, are more sensitive to changes in pH and cannot tolerate highly acidic environments as well as fungi can.

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14.

Water loss from a cell is referred to as what?

Correct Answer(s)
Plasmolysis

Explanation
Plasmolysis refers to the process of water loss from a cell. It occurs when there is a higher concentration of solutes outside the cell compared to the inside. As a result, water moves out of the cell through osmosis, causing the cell to shrink and the plasma membrane to detach from the cell wall. Plasmolysis can be reversible if water is added back to the cell, allowing it to regain its original shape and size.

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15.

Strong sugar and salt concentrations affect the water within a cell how?

Correct Answer(s)
Pull it out

Explanation
When there is a strong concentration of sugar and salt outside the cell, it creates a hypertonic environment. In this situation, water tends to move out of the cell through osmosis, resulting in the cell losing water and shrinking. Therefore, the correct answer "Pull it out" refers to the water being pulled out of the cell due to the strong sugar and salt concentrations outside.

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16.

In relation to bacteria, how do fungi respond to water?

Correct Answer(s)
They require less

Explanation
Fungi require less water compared to bacteria. This is because fungi have a unique structure that allows them to absorb moisture from their surroundings, including the air and the substrate they are growing on. They have hyphae, which are thin, thread-like structures that can efficiently absorb water and nutrients. In contrast, bacteria rely on being in a water-rich environment to survive and reproduce. Therefore, fungi have adapted to require less water for their growth and survival.

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17.

The structural backbone of all organic molecules an organism makes is what?

Correct Answer(s)
Carbon

Explanation
Carbon is the structural backbone of all organic molecules because it has the unique ability to form covalent bonds with other carbon atoms, as well as with other elements such as hydrogen, oxygen, nitrogen, and sulfur. This allows carbon to form long chains and rings, giving rise to the diverse and complex structures found in organic compounds. Carbon's versatility in bonding makes it essential for the formation of proteins, carbohydrates, lipids, and nucleic acids, which are the building blocks of life.

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18.

Carbon comes from CO2 in...

Correct Answer(s)
Autotrophs

Explanation
Autotrophs are organisms that can produce their own food using energy from the sun or inorganic substances. They are able to convert carbon dioxide (CO2) into organic compounds through the process of photosynthesis. This is how carbon is obtained from CO2 in autotrophs.

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19.

Carbon comes from food in...

Correct Answer(s)
Heterotrophs

Explanation
Carbon comes from food in heterotrophs because heterotrophs are organisms that cannot produce their own food through photosynthesis. Instead, they obtain carbon and other nutrients by consuming other organisms or organic matter. This means that the carbon present in the food they consume is used by heterotrophs for their own growth, energy production, and other metabolic processes. Therefore, carbon is derived from food in heterotrophs.

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20.

Nitrogen is required for the production of what?

Correct Answer(s)
ATP, DNA, RNA, and protien

Explanation
Nitrogen is required for the production of ATP, DNA, RNA, and protein. Nitrogen is an essential component of amino acids, which are the building blocks of proteins. ATP, DNA, and RNA all contain nitrogenous bases, which are crucial for their structure and function. Without nitrogen, the synthesis of these important molecules would be impaired, leading to various cellular and physiological dysfunctions.

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21.

Oxygen is used for energy through what process?

Correct Answer(s)
Aerobic respiration

Explanation
Aerobic respiration is the process by which cells use oxygen to convert glucose into energy. During this process, glucose is broken down in the presence of oxygen to produce carbon dioxide, water, and a large amount of ATP (adenosine triphosphate), which is the energy currency of the cell. This process is highly efficient and allows for the production of a significant amount of energy.

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22.

Oxygen helps in the process of aerobic respiration by doing what?

Correct Answer(s)
Breaking down sugars

Explanation
Oxygen helps in the process of aerobic respiration by breaking down sugars. During aerobic respiration, glucose molecules are broken down in the presence of oxygen to produce energy in the form of ATP. This process occurs in the mitochondria of cells and is essential for the functioning of organisms. Oxygen acts as the final electron acceptor in the electron transport chain, allowing for the efficient production of ATP through oxidative phosphorylation. By breaking down sugars, oxygen enables the release of energy needed for various cellular processes.

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23.

An oxygen environment is toxic because of what?

Correct Answer(s)
Free radicals and singlet atoms

Explanation
An oxygen environment is toxic due to the presence of free radicals and singlet atoms. These highly reactive species can cause damage to cells and tissues by oxidizing molecules in the body. Free radicals are unstable molecules with unpaired electrons, while singlet atoms are atoms in an excited state. Both can initiate chain reactions that lead to oxidative stress and cellular damage, contributing to various diseases and aging processes.

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24.

If an organism is going to live in an Oxygen environment, it requires what?

Correct Answer(s)
Protection from free radicals

Explanation
Living in an oxygen environment exposes organisms to the risk of free radicals, which are highly reactive molecules that can cause damage to cells and DNA. Therefore, in order to survive in such an environment, organisms need protection from free radicals. This can be achieved through various mechanisms, such as the production of antioxidant enzymes or the presence of antioxidant molecules that neutralize free radicals and prevent their harmful effects. Without this protection, the organism would be susceptible to oxidative stress and potential damage to its cellular components.

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25.

SOD is an abbreviation for what?

Correct Answer(s)
Superoxide dismutase

Explanation
SOD is an abbreviation for Superoxide dismutase. Superoxide dismutase is an enzyme that helps in the breakdown of superoxide radicals, which are harmful byproducts of cellular metabolism. It plays a crucial role in protecting cells from oxidative stress and preventing damage to DNA, proteins, and lipids. SOD is found in various organisms, including humans, and its dysfunction has been linked to various diseases, including neurodegenerative disorders and cancer.

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26.

Superoxide dismutase is used by the cell to do what?

Correct Answer(s)
Combine oxygen radicals with hydrogen

Explanation
Superoxide dismutase is an enzyme used by cells to catalyze the conversion of superoxide radicals into hydrogen peroxide and molecular oxygen. This process helps to protect the cell from the harmful effects of superoxide radicals, which are highly reactive and can cause damage to DNA, proteins, and other cellular components. By combining oxygen radicals with hydrogen, superoxide dismutase helps to maintain the balance of reactive oxygen species in the cell and prevent oxidative stress.

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27.

When oxygen radicals are combined with hydrogen, what is the resulting product?

Correct Answer(s)
H2O2 and O2

Explanation
When oxygen radicals combine with hydrogen, the resulting products are hydrogen peroxide (H2O2) and oxygen (O2). Oxygen radicals are highly reactive species that contain unpaired electrons, and when they react with hydrogen, they form hydrogen peroxide, which is a compound composed of two hydrogen atoms and two oxygen atoms. Additionally, the reaction also produces oxygen gas (O2), which is released as a byproduct.

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28.

What chemical agent is used to split H2O2 into water and oxygen gas?

Correct Answer(s)
Catalase

Explanation
Catalase is an enzyme that catalyzes the decomposition of hydrogen peroxide (H2O2) into water (H2O) and oxygen gas (O2). It speeds up the reaction by lowering the activation energy required for the decomposition of H2O2. Therefore, catalase is the chemical agent used to split H2O2 into water and oxygen gas.

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29.

What role does catalase play in the protection of bacterium from free radicals?

Correct Answer(s)
Splits H2O2 into water and oxygen gas

Explanation
Catalase is an enzyme that plays a crucial role in protecting bacteria from free radicals. It accomplishes this by breaking down hydrogen peroxide (H2O2) into water (H2O) and oxygen gas (O2). Hydrogen peroxide is a reactive molecule that can generate harmful free radicals, which can damage the bacterial cells. By catalyzing the decomposition of hydrogen peroxide, catalase prevents the accumulation of this potentially toxic molecule and helps maintain the overall integrity and survival of the bacterium.

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