Smartbook CH. 7 Flashcards
______ is the acquisition of chemical substances by organisms for use as an energy source or as building blocks of cellular structures
Nutrition
all of the chemical reactions that occur in a cell/organism to break down or build up molecules
Metabolism
All living things have an absolute need for _____ , such as carbon, hydrogen and oxygen.
bioelements
Any chemical substance required in small quantities, such as a trace metal, is termed a _______
micronutrient
are chemical substances, such as sugars or amino acids, that are required in large quantities by cells.
macronutrients
Micronutrients (zinc, manganese) that are required by cells in small amounts are termed
trace elements
The acquisition of chemical substances by organisms for the building blocks of cellular components and processes is
nutrition
________ play an important role in enzyme function and protein structure.
Micronutrients
List bioelements
hydrogen
oxygen
nitrogen
phosphorus
carbon
What term describes any chemical substance required in small quantities, such as a trace metal?
Micronutrient
Molecules that contain a basic framework of carbon and hydrogen are called
organic nutrients
Which term describes chemical substances such as carbon, hydrogen, and oxygen that are required in large quantities by cells?
Macronutrient
Nutrient sources for all living organisms can be acquired from
organic and inorganic compounds
Carbohydrates, nucleic acids, and lipids are examples of ______ compounds
organic compounds
The function of micronutrients, or trace elements is
maintenance of protein structure
proper enzyme function
All living things have an absolute need for _____ , such as carbon, hydrogen and oxygen.
bioelements
Examples of _______ nutrients include magnesium sulfate, ferric nitrate, sodium phosphate, carbon dioxide, and water.
inorganic
Molecules that contain a basic framework of carbon and hydrogen and are nearly always produced by living things are called ______ nutrients.
organic
Which must acquire its chemical energy from some outside source?
Heterotroph
Living organisms obtain nutrients from ________ sources.
both organic and inorganic sources
Because cells cannot synthesize all 20 amino acids required for growth, these amino acids are termed ________ amino acids.
essential amino acids
Which of the following are organic nutrients?
Carbohydrates
Proteins
Methane
Nucleic acids
The energy source for phototrophs is the _______, while the energy source for chemotrophs is ________.
sun, chemical compounds
Organic compounds are the carbon and energy source for heterotrophs.
true
An ______ nutrient is composed of an element or elements other than carbon and hydrogen.
inorganic nutrient
The principal energy-yielding pathway that involves the breakdown of glucose in the presence of oxygen is called
aerobic respiration or cellular respiration
An organism that uses inorganic CO2 as its carbon source is called a _____, while an organism that must obtain its carbon in an organic form is referred to as a ______
autotroph , heterotroph
Microorganisms that are human pathogens are best described as which of the following nutritional types?
Heterotrophic
Microorganisms that are human pathogens are best described as which of the following nutritional types?
Heterotrophic
When a normally nonpathogenic saprobe causes infection in a compromised host, it is referred to as a
opportunistic pathogen
A _____ is any organism that obtains its nutrients from the cells or tissues by taking them from another living host.
parasite
Any microorganism that causes disease is a
pathogen
_______ involves the complete breakdown of glucose to yield carbon dioxide, water, and energy in the form of ATP.
Aerobic respiration
The cell ______ is specialized to transport substances into and out of the cell.
cell membrane
Many gardeners practice composting, where leftover vegetable peels, leaves, and other organic matter is collected and turned into a rich, fertile soil. Which best describes the type of microbes in compost?
Saprophytic
By the process of ______ transport, molecules move through a cell membrane without the expenditure of cellular energy.
passive transport
_______ pathogens are usually nonpathogenic microbes that cause disease in a compromised host.
Opportunistic pathogens
Organisms that derive nutrients from the living hosts are called _______.
parasites
______ is the diffusion of water across a selectively permeable membrane in the direction of lower water concentration.
osmosis
Membranes that only allow certain compounds into or out of the cell are called ______.
selective
Which of the following cell structures is specialized for transport of materials into and out of the cell?
Cell membrane
A solution in which the concentration of solutes is the same on both sides of a membrane is
isotonic
What term is used to describe the movement of molecules through a cell membrane without the need of an energy source?
Passive transport
If a cell is in a solution that is hypotonic relative to the cytoplasm, how will water move?
Into the cell by osmosis
If a cell loses water after being placed into a particular solution, what is true regarding the osmolarity of the solution?
The solution is hypertonic relative to the cell.
Which term is used exclusively to describe water’s movement across a selectively permeable membrane?
Osmosis
Bacterial cells placed in a solution where the concentration of solute within the cytoplasm is less than that of the extracellular solution would undergo ______.
plasmolysis (shrinkage)
A ______ permeable membrane can allow specific compounds into the cell and/or out of the cell.
selectively
The high ______ of a hypertonic environment causes water to diffuse out of a cell.
osmotic pressure
Which of the following would describe a solution which is well balanced for a cell?
Isotonic
Prior to refrigeration, salting was used to prevent microbial growth in foods by causing ______ in bacterial cells.
plasmolysis
Which type of solution will cause a cell to swell with water?
Hypotonic
______ transport requires ATP, whereas ______ transport does not require cell energy expenditure.
active, passive
Which type of solution contains a higher concentration of solutes?
hypertonic
What term is used to describe the “best” temperature to support a microbe’s growth?
Optimal temperature
______ occurs to a bacterial cell when it loses water due to an environment that has far more solutes outside the cell compared to inside.
Plasmolysis
From which environment would you most likely observe growth of psychrophilic microorganisms?
Frozen food
The osmotic pressure of a hypertonic environment is ______ forcing water to diffuse ______ a cell.
high; out of
Microbes that can grow slowly in cold temperatures, but have optimum temperatures above 20°C, are called ______.
psychrotrophs
These require very cold temperatures, such as those below 15 C, as their optimum.
psychrophiles
Prior to refrigeration, how did salting prevent microbial growth in foods?
Osmotic pressure killed the bacteria
Because mesophilic bacteria have an optimal temperature of ___________ degrees Celsius (same as human body temperature), they are the largest group of medically important microorganisms.
37
Microorganisms that grow at intermediate temperatures—usually between 20 and 40 degrees C.
mesophile
Which of the following main categories of transport involves the movement of molecules against the concentration gradient?
active transport
Which type of microbes are a common contaminant of pasteurized or heated foods?
Thermoduric microbes
The temperature at which a species shows the most rapid growth rate is known as the cell’s _______
optimum temperature
Microorganisms that prefer hot environments in the range of 45°C to 80°C are called ______
thermophiles
Which term describes a microorganism that thrives and divides under refrigeration conditions?
Psychrophile
prefer a temperature range between 20°C and 40°C
Mesophiles
_______ can grow in the cold and are able to cause food-borne illness, but are not true psychrophiles.
Psychrotrophs
Facultative psychrophiles
Choose the temperature range of most mesophilic microorganisms
20°C-40°C
Microorganisms that are normally mesophiles, but can handle short exposures to high temperatures are called
thermoduric microbes
Where would a thermophilic microorganism be found?
In natural hot springs
The two atmospheric gases that have the greatest impact on microbial growth are
oxygen and carbon dioxide
From which environment would you most likely observe growth of psychrophilic microorganisms?
Frozen food (below 20 C)
The enzyme ______ converts hydrogen peroxide formed during aerobic respiration to water and oxygen.
catalase or peroxidase
Microbes that can grow slowly in cold temperatures, but have optimum temperatures above 20°C, are called ______.
psychrotrophs
can grow from 10 to 50oC
Mesophiles
require very cold temperatures, such as those below 15oC
psychrophiles
What word is used to describe organisms which can use oxygen in their cellular respiration pathways?
Aerobic
What word describes a microbe that must have oxygen to survive?
Obligate aerobe
Which type of microbes are a common contaminant of pasteurized or heated foods?
Thermoduric microbes
facultative anaerobe
Can grow in the absence of oxygen
Prefers using oxygen if present
Produces energy by respiration or fermentation pathways
is any microorganism that grows best in the absence of oxygen.
anaerobe
Hydrogen peroxide is converted into water and oxygen by the enzyme _______.
catalase
To obligate anaerobes, oxygen is ______ and ______.
toxic, not used
is a microorganism that can use oxygen in metabolism and process toxic oxygen products.
aerobe
______ or strictly aerobic organism, requires oxygen for survival.
obligate aerobe
are organisms that thrive in environments with a pH close to 7.
Neutrophiles
is capable of growing in aerobic and anaerobic conditions.
facultative anaerobe
is an organism that prefers a habitat where the pH is below 7.
acidophile
What word is used to describe organisms which do NOT use oxygen in their cellular respiration pathways?
Anaerobic
Which term describes a microbe that grows in environments with a pH greater than 7?
Alkalinophile
Oxygen is toxic to obligate anaerobes because these organisms lack the enzymes to degrade toxic products of aerobic metabolism.
True
Obligate anaerobes do not produce
catalase or superoxide dismutase, so are unable to destroy these products if formed from even brief exposure to oxygen.
specifically requires a high concentration of salt for growth.
halophile
______ microorganism requires the absence of oxygen for survival.
strict or obligate
An organism that requires a high salt environment for optimal growth is a(n) ______ halophile.
obligate
What term is used to describe organisms that exist in environments near the pH of 7?
Neutrophiles
Which term describes any close relationship between two organisms?
Symbiosis
Which name is given to microbes that grow in environments where the pH is lower than 7?
Acidophiles
Which of the following describes a type of symbiotic relationship between two organisms in which both species benefit?
Mutualism
An organism that prefers a pH of above 7 is referred to as a
alkalinophile
Which term describes bacteria that require or tolerate high concentrations of salt?
Halophile
Which of the following is defined as a relationship between organisms where one benefits and the other is unharmed?
Commensalism
can tolerate high salt concentrations even though they do not normally reside in such environments.
facultative halophile
A symbiotic relationship where one organisms benefits at the expense of another is termed ____.
parasitism
is a close association between individuals from two species that may be helpful, harmful or neither to both members.
Symbiosis
A relationship in which the products given off by one organism are usable as nutrients for another organism is called ______.
syntrophy
A relationship where microorganisms compete for survival in a common environment is known as
amensalism or antagonism
In one form of amensalism, microbes release specific chemicals called ______ into the environment to inhibit or kill other microbes.
antibiotics
A beneficial relationship involving communal feeding between organisms sharing a habitat is called
syntrophy or crossfeeding
The normal resident bacteria found in or on the human body are collectively called the ______.
microbiota
Which of the following describes a relationship where microorganisms compete for survival in a common environment?
Amensalism
binary fission
Daughter cells are identical to each other.
Binary fission occurs only once in the life of a single cell.
It is a type of asexual reproduction.
Antibiotics released by one microbe to inhibit or kill other microbes demonstrates an antagonistic relationship called
amensalism
In binary fission, the doubling time of a particular microbial species is also known as its
generation time
The time required for a complete fission cycle—from parent cell to two new daughter cells
generation time
Which of the following is defined as a relationship between organisms where one benefits and the other is unharmed?
Commensalism
occurs when BOTH organisms benefit from the relationship.
Mutualism
Put the phases of a normal population growth curve in order
Lag phase
Log Phase
Stationary Phase
Dead Phase
When organisms attach to a substrate and secrete an extracellular matrix, a _______ is formed.
biofilm
is when a bacterial cell is placed into a new environment and cell division is slow.
Lag phase
The bacteria that normally inhabit the skin, GI tract, and other body sites are also referred to as normal resident________
microbiota
During the ______ phase of microbial growth, numbers of cells are difficult to count because cells are adjusting to growth media, they have not reached their maximum growth rate, and the overall number of cells is sparse.
lag phase
Bacteria reproduce by
binary fission
The log phase of a normal growth curve is also referred to as the
exponential growth phase
Which term describes the length of time of a microbial species needs to divide?
Generation time
Which of the following characterizes the lag phase of a normal bacterial growth curve?
Little increase in cell numbers
when the population is growing at less than the exponential rate?
lag phase
Exponential decline occurs during the
death phase
These events characterize the stationary phase after cell division occurs.
Depletion of nutrients and build up of waste
The ______ phase of bacterial cell growth is when the number of cells dividing equals the number of cells that are dying.
stationary or stationary growth
Limited growth during the lag phase of a growth curve is due to the need for cells to
synthesize new enzymes to metabolize nutrients in the culture media.
The _____ phase of the population growth curve involves very little cell division and an exponential decline in numbers.
death
In which phase of bacterial growth are far more cells dividing than dying?
Exponential
Which phase of bacterial growth involves more cells dying than reproducing?
Death
Microbes that normally live on the skin, in the gastrointestinal tract, and in other sites are called the normal resident __________.
microbiota
Organisms referred to as __________ halophiles require at least a 9% salt concentration in order to grow, whereas __________ halophiles can adapt to a wide range of solute concentrations.
obligate; facultative
cells require a period of adjustment after being newly inoculated
lag phase
population reaches maximum growth rate
exponential growth phase
rate of cell inhibition and cell death balances the rate of multiplication, and population size remains constant
stationary growth phase
population declines as death of cells exceeds rate of multiplication
death phase
can use gaseous oxygen and possesses enzymes to process toxic oxygen products.
aerobe
______ aerobe cannot grow without oxygen.
obligate aerobe
metabolize by aerobic respiration but can adapt to anaerobic environments.
facultative anaerobes
can only tolerate very minute concentrations of oxygen in their environment
Microaerophiles
_____ represent a final group of organisms, whose members lack the required enzymes needed for using oxygen in respiration and may not be able to tolerate any free oxygen in their environment _____
Anaerobes, strict anaerobes
organisms living in obligatory but mutually beneficial relationships
mutualism
one organism benefits while the other organism is neither harmed nor benefited
commensalism
one organism is harmed when it provides the other organism with nutrients and a habitat
parasitism
Bacteria found in the stomach of cud-chewing mammals, such as cows, are essential in the breakdown of cellulose. This relationship is an example of __________.
endosymbiosis
The most common organisms causing food spoilage are bacteria, _____, _____
yeasts, and molds.
food spoilage microorganisms can be classified by their
growth temperature preferences
normal habitat of Pseudomonas aeruginosa is
soil and water
Pseudomonas produces a slime layer composed of
polysaccharides
An acidophile lives in what pH environment?
pH 0–6
Extremophiles are able to live in toxic environments due to
evolution of genetic traits
Osmosis is best defined as the movement of
water molecules across a membrane from an area of high water concentration to an area of lower concentration
Osmosis, Which of the following will pass through a cell membrane most easily?
small nonpolar molecules
In a hypertonic medium, water will pass from the cell to the surrounding _____
environment
A red blood cell placed in a hypertonic medium will
shrink
A 5% urea solution is hypotonic to a 10% urea solution.
true
The environment inside the cell has the same solute concentration as the environment outside of the cell.
isotonic
The environment inside the cell has a lower solute concentration than the environment outside the cell.
hypertonic
The environment inside the cell has a higher solute concentration than the environment outside the cell.
hypotonic
