BIO 175 EXAM #2 QUESTIONS WITH
100%RATED ANSWERS 2024/2025 LATEST
UPDATED/GET A+
List the essential nutrients of a bacterial cell - -carbon, hydrogen, oxygen, nitrogen, phosphorus,
sulfur, potassium, calcium, iron, chlorine, and magnesium
Differentiate between macronutrients and micronutrients - -any substance that must be provided
to an organism is called an essential nutrient, which have two categories
-macronutrients: required in relatively larger quantities and play principal roles in cell structure
and metabolism; examples are carbon, hydrogen, and oxygen
-micronutrients: also called trace elements, which are present in smaller amounts and are
involved in enzyme function and maintenance of protein structure; examples are manganese,
zinc, and nickel
List and define four different terms that describe an organism's sources of carbon and energy - -
heterotroph: relies on organic compounds for its carbon and energy needs
-autotroph: "self-feeder" requires inorganic nutrients and whose sole source of carbon is carbon
dioxide; not nutrientally dependent on other living things
-phototrophs: microbes that photosynthesize or create energy from sunlight
-chemotrophs: those that get their energy from chemical compounds
Define saprobe and parasite, and explain why these terms can be oversimplification - -saprobe:
decomposers of plants, animals, and dead microbes
-parasite: live in or on the body of the host, which they harm to some degree
-these are considered chemoheterotrophs
-might be better to call the categories "saprobes" and "nonsaprobe" since scientists have learned
that not all organisms that require a living host necessarily harm the host
,Compare and contrast the processes of diffusion and osmosis - -whatever the direction, transport
occurs in the cytoplasmic membrane, the structure specialized for this role
-diffusion: phenomenon of molecular movement, in which atoms or molecules move in a
gradient from an area of high concentration to an area of low concentration
-osmosis: diffusion of water through selectively permeable membrane, is a physical phenomenon
that is easily demonstrated in the lab with nonliving materials; it provides a model of how cells
deal with various solute concentrations in aqueous solutions
-in an osmotic system, the membrane is selectively permeable, having passageways that allow
free diffusion of water but that block certain molecules
-when this membrane is placed between solutions of differing concentrations and the solute can't
pass through the membrane, then under the laws of diffusion, water will diffuse at a faster rate
from the side that has more water to the side that has less water
-as long as the concentrations of the solutions differ, one side will experience a net loss of water
and the other a net gain of water, until equilibrium is reached and the rate of diffusion is
equalized
Identify the effects of isotonic, hypotonic, hypertonic conditions on a cell - -isotonic: the
environment is equal in solute concentration to the cell's internal environment, and bc diffusion
of water proceeds at the same rate in both directions, there is no net change in cell volume; most
stable
-hypotonic: the solute concentration of the external environment is lower than that of the cell's
internal environment; causes cell to swell but the cell wall usually helps it from not bursting
-hypertonic: water diffuses out of cell and shrinks the cytoplasmic membrane away from the cell
wall; it is said to have high osmotic pressure; microbes can't metabolize since membrane is
wrinkled up
Name two types of passive transport and one type of active transport - passive transport
-simple diffusion: property of atoms and molecules that exist in a state of random motion; doesn't
need any energy requirements since substances move on a gradient from higher concentration to
lower concentration
,-facilitated diffusion: molecule binds to specific receptor in membrane and is carried to the other
side, molecule specific, goes both directions, rate of transport is limited by the number of binding
sites of transporting proteins; doesn't have any energy requirements since substances move on a
gradient from higher concentration to lower concentration
Active transport
-carrier mediated active transport: atoms or molecules are pumped into or out of the cell by
specialized receptors; driven by atp or the proton motive force
List and define five terms used to express the temperature related growth capabilities of microbes
- -psychrophile: has an optimum temp below 15 c and is still capable of growth at 0 c, it is
obligate with respect to cold and generally cannot grow above 20 c
-mesophiles: majority of medically significant microorganisms that grow at intermediate temps
with falls into a range of 20 c to 40 c
-thermophile: a microbe that grows optimally at temps greater than 45 c to 80 c
Summarize three ways in which microorganisms function in the presence of differing oxygen
conditions - -those that use oxygen and can detoxify it
-those that can neither use oxygen nor detoxify it
-those that do not use oxygen but can detoxify it
Identify three important environmental factors (other than temperature and oxygen) with which
organisms must cope - -radiation and hydrostatic/atmospheric pressure
-ph: as the value decreases toward 0, the acidity increases and as the ph increases towards 14, the
alkalinity (basic) increases
-osmotic pressure: osmophiles which live in habitats with a high solute concentration
List and describe the five types of associations microbes can have with their hosts - symbiosis: a
situation in which two organisms live together in a close partnership
-mutualism: when organisms live in a mutually beneficial relationship; the microbes receive
necessary nutrients and the host gets a variety of benefits, ranging from protection from
pathogenic microbes to the healthy development of the immune system
, -commensalism: an unequal relationship in which one species derives benefit without harming
the other
-parasitism: a relationship in which the host organism provides the parasitic microbe with
nutrients and a habitat and the host suffers from the relationship
Nonsymbiotic: organisms are free living; relationships not required for survival results in a
heightened response or greater activity
-synergism: the coordinated or correlated action by two or more drugs or microbes that
-antagonism: relationship in which microorganisms compete for survival in a common
environment by taking actions that inhibit or destroy another organism
Discuss characteristics of biofilms that differentiate them from planktonic bacteria - -biofilms are
communities of bacteria and/or other microbes that are attached to a surface and to each other,
forming a multilayer conglomerate of cells and intracellular material
-bacteria can use quorum sensing to interact with other members of the same species, as well as
members of other species that are close by
-eventually large complex communities are formed, which have different physical and biological
characteristics in different locations of the community
-the bottom of a biofilm may have a very different ph and oxygen conditions than the surface of
a biofilm; it is clearly established that microbes in a biofilm, as opposed to those in a planktonic
(free floating) state, behave and respond very differently in their environments
-different genes are even activated in the two situation and at any rate, a single biofilm is actually
a partnership among multiple microbial inhabitants and thus cannot be eradicated by traditional
methods targeting individual infections
Summarize the steps of cell division used by most bacteria - -binary fission: the formation of two
new cells
-the parent cell enlarges, duplicated its chromosome, and then starts to pull its cell envelope
together in the center of the cell using a band of protein that is made of substance that resemble
actin and tubular (the protein in microtubules in eukaryotic cells)
-the cell wall eventually forms a complete central septum and this process divides the cell into
two daughter cells and then is repeated
100%RATED ANSWERS 2024/2025 LATEST
UPDATED/GET A+
List the essential nutrients of a bacterial cell - -carbon, hydrogen, oxygen, nitrogen, phosphorus,
sulfur, potassium, calcium, iron, chlorine, and magnesium
Differentiate between macronutrients and micronutrients - -any substance that must be provided
to an organism is called an essential nutrient, which have two categories
-macronutrients: required in relatively larger quantities and play principal roles in cell structure
and metabolism; examples are carbon, hydrogen, and oxygen
-micronutrients: also called trace elements, which are present in smaller amounts and are
involved in enzyme function and maintenance of protein structure; examples are manganese,
zinc, and nickel
List and define four different terms that describe an organism's sources of carbon and energy - -
heterotroph: relies on organic compounds for its carbon and energy needs
-autotroph: "self-feeder" requires inorganic nutrients and whose sole source of carbon is carbon
dioxide; not nutrientally dependent on other living things
-phototrophs: microbes that photosynthesize or create energy from sunlight
-chemotrophs: those that get their energy from chemical compounds
Define saprobe and parasite, and explain why these terms can be oversimplification - -saprobe:
decomposers of plants, animals, and dead microbes
-parasite: live in or on the body of the host, which they harm to some degree
-these are considered chemoheterotrophs
-might be better to call the categories "saprobes" and "nonsaprobe" since scientists have learned
that not all organisms that require a living host necessarily harm the host
,Compare and contrast the processes of diffusion and osmosis - -whatever the direction, transport
occurs in the cytoplasmic membrane, the structure specialized for this role
-diffusion: phenomenon of molecular movement, in which atoms or molecules move in a
gradient from an area of high concentration to an area of low concentration
-osmosis: diffusion of water through selectively permeable membrane, is a physical phenomenon
that is easily demonstrated in the lab with nonliving materials; it provides a model of how cells
deal with various solute concentrations in aqueous solutions
-in an osmotic system, the membrane is selectively permeable, having passageways that allow
free diffusion of water but that block certain molecules
-when this membrane is placed between solutions of differing concentrations and the solute can't
pass through the membrane, then under the laws of diffusion, water will diffuse at a faster rate
from the side that has more water to the side that has less water
-as long as the concentrations of the solutions differ, one side will experience a net loss of water
and the other a net gain of water, until equilibrium is reached and the rate of diffusion is
equalized
Identify the effects of isotonic, hypotonic, hypertonic conditions on a cell - -isotonic: the
environment is equal in solute concentration to the cell's internal environment, and bc diffusion
of water proceeds at the same rate in both directions, there is no net change in cell volume; most
stable
-hypotonic: the solute concentration of the external environment is lower than that of the cell's
internal environment; causes cell to swell but the cell wall usually helps it from not bursting
-hypertonic: water diffuses out of cell and shrinks the cytoplasmic membrane away from the cell
wall; it is said to have high osmotic pressure; microbes can't metabolize since membrane is
wrinkled up
Name two types of passive transport and one type of active transport - passive transport
-simple diffusion: property of atoms and molecules that exist in a state of random motion; doesn't
need any energy requirements since substances move on a gradient from higher concentration to
lower concentration
,-facilitated diffusion: molecule binds to specific receptor in membrane and is carried to the other
side, molecule specific, goes both directions, rate of transport is limited by the number of binding
sites of transporting proteins; doesn't have any energy requirements since substances move on a
gradient from higher concentration to lower concentration
Active transport
-carrier mediated active transport: atoms or molecules are pumped into or out of the cell by
specialized receptors; driven by atp or the proton motive force
List and define five terms used to express the temperature related growth capabilities of microbes
- -psychrophile: has an optimum temp below 15 c and is still capable of growth at 0 c, it is
obligate with respect to cold and generally cannot grow above 20 c
-mesophiles: majority of medically significant microorganisms that grow at intermediate temps
with falls into a range of 20 c to 40 c
-thermophile: a microbe that grows optimally at temps greater than 45 c to 80 c
Summarize three ways in which microorganisms function in the presence of differing oxygen
conditions - -those that use oxygen and can detoxify it
-those that can neither use oxygen nor detoxify it
-those that do not use oxygen but can detoxify it
Identify three important environmental factors (other than temperature and oxygen) with which
organisms must cope - -radiation and hydrostatic/atmospheric pressure
-ph: as the value decreases toward 0, the acidity increases and as the ph increases towards 14, the
alkalinity (basic) increases
-osmotic pressure: osmophiles which live in habitats with a high solute concentration
List and describe the five types of associations microbes can have with their hosts - symbiosis: a
situation in which two organisms live together in a close partnership
-mutualism: when organisms live in a mutually beneficial relationship; the microbes receive
necessary nutrients and the host gets a variety of benefits, ranging from protection from
pathogenic microbes to the healthy development of the immune system
, -commensalism: an unequal relationship in which one species derives benefit without harming
the other
-parasitism: a relationship in which the host organism provides the parasitic microbe with
nutrients and a habitat and the host suffers from the relationship
Nonsymbiotic: organisms are free living; relationships not required for survival results in a
heightened response or greater activity
-synergism: the coordinated or correlated action by two or more drugs or microbes that
-antagonism: relationship in which microorganisms compete for survival in a common
environment by taking actions that inhibit or destroy another organism
Discuss characteristics of biofilms that differentiate them from planktonic bacteria - -biofilms are
communities of bacteria and/or other microbes that are attached to a surface and to each other,
forming a multilayer conglomerate of cells and intracellular material
-bacteria can use quorum sensing to interact with other members of the same species, as well as
members of other species that are close by
-eventually large complex communities are formed, which have different physical and biological
characteristics in different locations of the community
-the bottom of a biofilm may have a very different ph and oxygen conditions than the surface of
a biofilm; it is clearly established that microbes in a biofilm, as opposed to those in a planktonic
(free floating) state, behave and respond very differently in their environments
-different genes are even activated in the two situation and at any rate, a single biofilm is actually
a partnership among multiple microbial inhabitants and thus cannot be eradicated by traditional
methods targeting individual infections
Summarize the steps of cell division used by most bacteria - -binary fission: the formation of two
new cells
-the parent cell enlarges, duplicated its chromosome, and then starts to pull its cell envelope
together in the center of the cell using a band of protein that is made of substance that resemble
actin and tubular (the protein in microtubules in eukaryotic cells)
-the cell wall eventually forms a complete central septum and this process divides the cell into
two daughter cells and then is repeated
