40 Questions
What is the primary function of photosynthetic pigments in phototrophs?
To trap energy in the form of light
Which of the following molecules is NOT a high-energy compound that stores energy for cellular use?
Glucose
What is the primary source of sulfur for the synthesis of sulfur-containing amino acids?
Organic sulfur compounds
Which ion is involved in the transport of solutes into the cell?
Na+
What is the primary function of oxygen in aerobic respiration?
To act as an electron acceptor
Which element is a component of cell membranes, cell walls, and ribosomes?
Mg
What is the primary function of iron in the cell?
To act as a co-factor for enzymes
Which of the following elements is NOT a component of carbohydrates, lipids, proteins, and nucleic acids?
Fe
What is the terminal electron acceptor in aerobic respiration?
Oxygen
Which of the following is NOT a characteristic of cytochromes?
Aromatic compounds
What is the purpose of the electron transport chain in cellular respiration?
To generate ATP through oxidative phosphorylation
What is the end product of oxidative phosphorylation?
ATP and water
Which of the following is an example of anaerobic respiration?
Respiration using nitrate as the terminal electron acceptor
What is the process of reducing nitrate to gaseous nitrogen compounds?
Denitrification
Which of the following is a characteristic of quinones?
Aromatic compounds
What is the purpose of the electron transport chain in generating ATP?
To pump protons across the membrane
What is the purpose of superoxide dismutase in organisms that live in the presence of oxygen?
To convert superoxide anions into oxygen and hydrogen peroxide
Which enzyme is responsible for degrading hydrogen peroxide into water and oxygen in most bacteria?
Catalase
What is the purpose of the candle jar in culturing certain bacteria?
To decrease the concentration of oxygen
Which type of bacteria requires specialized conditions where all oxygen is removed from the environment?
Anaerobes
What is the byproduct of the reaction catalyzed by superoxide dismutase?
Oxygen and hydrogen peroxide
What is the purpose of the CO2 generating kit in anaerobic jars?
To increase the concentration of CO2
What is the result of the reaction catalyzed by catalase?
Hydrogen peroxide is converted into water and oxygen
Which type of bacteria possesses peroxidase to reduce hydrogen peroxide?
Aerotolerant anaerobes
Which statement accurately describes passive diffusion?
It is driven by the concentration gradient of solutes.
What role do permeases play in facilitated diffusion?
They act as carriers for specific solute molecules.
Why can the rate of facilitated diffusion plateau?
Because all available permeases become saturated.
In which temperature range do mesophiles grow optimally?
30°C to 40°C
Which type of bacteria is typically responsible for food spoilage in refrigerators?
Psychrotrophs
Which molecules are likely to cross membranes via passive diffusion?
Lipids such as glycerol and small molecules like water, CO2, and O2
How does facilitated diffusion differ from passive diffusion?
Facilitated diffusion uses carrier proteins to aid solute transport while passive diffusion does not.
Which organism can be classified as a psychrotroph?
Pseudomonas fluorescens
What happens when the concentration gradient in passive diffusion decreases?
The rate of inward movement of molecules slows down until equilibrium is reached.
What characteristic of hyperthermophiles' plasma membranes allows them to withstand high temperatures?
Phytane, a branched saturated isoprenoid
What is one characteristic of facilitated diffusion?
It can reverse the direction of transport depending on solute concentration.
Where are the majority of hyperthermophiles typically found?
Thermal vents of the sea floor
What adaptation allows psychrophiles' cell membranes to remain semi-fluid in cold temperatures?
High concentrations of unsaturated fatty acids
What types of molecules does Escherichia coli have multiple transport mechanisms for?
Galactose and leucine
Why are psychrophiles unable to function at body temperature (37°C)?
Their protein synthesis systems are heat-sensitive
What is a common trait of thermophiles that allows their plasma membranes to withstand high temperatures?
Saturated lipids with a high melting point
Learn about phototrophs, autotrophs, and heterotrophic bacteria, and how they obtain and convert energy through photosynthesis and cellular processes.
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