Chapter 6 Flashcards
Any substance that must be provided to an organism
Essential nutrient
Required in relatively large quantities and play principal roles in cell structure and metabolism
Examples:
- Carbon
- Oxygen
- Hydrogen
Macronutrients
Present in much smaller amounts and are involved in enzyme function and maintenance of of protein structure.
Examples:
- Magnesium
- Zinc
- Nickel
Micronutrients or trace elements
Categorizing Nutrients According to their Carbon Content
Inorganic Nutrient
6.1 Outcome
Differentiate between macronutrients and micronutrients.
Macronutrients are required in larger quantities; they play principal roles in cell structure and metabolism
-carbon, hydrogen, oxygen
Micronutrients are required in much smaller amounts; they are involved in enzyme function and maintenance of protein structure
-zinc, nickel, manganese
An atom or simple molecule that contains a combination of atoms other than carbon and hydrogen
-natural reservoirs are the crust of the earth, bodies of water, and the atmosphere
Inorganic Nutrient
List examples of inorganic nutrients
metals and their salts such as magnesium sulfate, ferric nitrate
gases like o2, co2
water
Molecules contain carbon and hydrogen atoms and are usually the product of living things
Organic nutrients
List examples of organic nutrients
methane (CH4), and large polymers such as carbos, lipids, proteins, and nucleic acids
Some microbes obtain their nutrients entirely from inorganic sources and other require a _________ of organic and inorganic sources
combination
What percent of the dry cell weight is composed of organic compounds?
97%
About 96% of the dry cell weight is composed of just six elements, what are they?
CHONPS
carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur
The main determinants of a microbe’s nutritional type are its source of ______ and its source of _____.
carbon; energy
An organism that must obtain its carbon in an organic form
Heterotroph
An organism that uses inorganic CO2 as its carbon source
- has the capacity to convert CO2 into organic compounds
- not nutritionally dependent on living things
Autotrophs
Microbes that photosynthesize
Phototrophs
Microbes that get their energy from chemical compounds
Chemotrophs
What microbes use CO2 as carbon source?
Photoautotroph
Chemoautotroph
-Chemoorganic autotrophs
-Chemolithoautotrophs
What microbes use organic carbon as a carbon source?
photoheterotroph
chemoheterotrophs
saprobe
parasite
Define saprobe and parasite and explain why these terms
can be an oversimplification.
Saprobe: free-living organisms that feed on organic detritus from dead organisms
Parasites: derive nutrients from the cells or tissues of a living host
(range from helminths to viruses)
Parasite is an oversimplification due to the fact that their are endo and ecto parasites that range from viruses to helminths.
-Obligate parasites: unable to grow outside of living host such as leprosy bacillus and syphilis spirochete
Saprobe is an oversimplification because they are decomposers and recycle organic nutrients
Chemoorganic Autotrophs
use organic compounds for energy and inorganic compounds as a carbon source
Lithoautotrophs
rely totally on inorganic minerals and require neither sunlight nor organic nutrients
Phototrophs vs Chemotrophs
P: microbes that use photosynthesis to feed
C: organisms that oxidize compounds to feed on nutrients
Essential to protein synthesis and membrane function
Potassium (K)
important for certain types of cell transport
Sodium (Na)
Stabilizer of cell wall and endospores of bacteria
Calcium (Ca)
component of chlorophyll and a stabilizer of membranes and ribosomes
Magnesium (Mg)
Important component of the cytochrome proteins of cell respiration
Iron (Fe)
Essential regulatory element for eukaryotic genetics
Zinc (Zn)
Derive both carbon and energy from organic compounds
Chemoheterotrophs
Two main categories of chemoheterotrophs
Saprobes (free living organisms that feed primarily on organic detritus from dead organisms)
Parasites (derive organisms from cells or tissues of living hosts)
If not for the work of these decomposers the earth would gradually fill up with organic material and the nutrients it contains would not be recycled
Saprobes
Most extreme form of parasite
Intracellular parasite
Ectoparasite
lives on the body of the host
Endoparasite
lives on organs or tissues of host
List the mineral ions used in microbial nutrition
sodium
potassium
calcium
magnesium
List two bacteria that can grow on artificial media
Streptococcus pyogenes (strep throat)
Staphylococcus aureus
The vast majority of microbes causing human disease are ________.
chemoheterotrophs
CHONPS are the ______ _______ for microbes.
essential nutrients
Among the common organic molecules that can satisfy this requirement are proteins, carbs, lipids, and nucleic acids.
Carbon
Is a major element in all organic and several inorganic compounds, including water, salts, and certain naturally occurring gases like methane (these gases are used and produced by microbes)
- Helps maintain cell’s pH, and is useful for forming ____ bonds between molecules.
- source of free energy in respiration
hydrogen
Plays an important role in the structural and enzymatic functions of the cell.
Major component of organic compounds such as carbs, lipids, and nucleic acid, and proteins.
- a component of inorganic salts such as sulfates, phosphates, nitrates, and water.
- free gaseous ____ makes up 20% of the atmosphere
oxygen
Indispensable to the structure of proteins, DNA, RNA, and ATP
this gas (N2) makes up 79% of the earth’s atmosphere
Nitrogen
Binding factor that helps enzymes adhere to specific sites on DNA
Zinc fingers
The bacteria that cause gonorrhea and meningitis grow more rapidly in the presence of _____.
Iron (Fe)
Transport of nutrients occurs across the ________ ________.
cytoplasmic membrane
Phenomenon of molecular movement in which atoms or molecules move in a gradient from an area of higher density/concentration to an area of lower density/concentration
->think of putting a drop of food coloring into a glass of water, its highly concentrated where the one drop fell, but then it disperses out to areas of lower concentration
Diffusion
Diffusion of water through a selectively permeable membrane is called _____.
Osmosis
Have a tonicity that is the same as the body’s plasma.
When administered there will be very little movement if any.
Isotonic solution
Tonicity that is higher then the body plasma.
Hypertonic
Tonicity lower than the body plasma, causing water to shift from the intravascular to the extravascular and eventually in cells.
burst
Hypotonic
Microorganisms living in host tissues are most likely to be living in ______ habitats
isotonic
Solute concentration of the external environment is lower than that of the internal environment
;may cause burst
hypotonic
Slight ________ is tolerated quite well by most bacteria because of their rigid cell walls.
hypotonicity
Substances move on a gradient from higher to lower concentration with no energy requirements
-limited to small nonpolar molecules like o2 or lipid-soluble molecules that may pass through the membranes
Simple Diffusion
-passive transport
Substances move on a gradient from higher to lower concentration; no energy required.
- molecules bind to specific receptors in the membrane and are carried to the other side.
- Molecule-specific and goes both directions
Facilitated Diffusion
-passive transport
Driven by ATP or the proton motive force; energy is require to move molecules
-Atoms or molecules are pumped into or out of the cell by specialized receptors
Carrier-Mediated active transport
-Active Transport
Examples of substances transported actively
Monosaccharides Amino acids Organic acids Phosphates Metal ions
A form of active transport carried out by eukaryotic cells that is not carrier-mediated
Endocytosis
The engulfment, or endocytosis, of liquids by extensions of the cell membrane.
Pinocytosis
A type of endocytosis in which the cell membrane actively engulfs large particles or cells into vesicles.
Phagocytosis
Minimum temperature
the lowest temperature that permits a microbe’s continued growth and metabolism
; below this temperature activity stops
Maximum temperature
is the highest temperature at which growth and metabolism can proceed
; if the temp rises slightly above maximum growth will temporarily stop -> if continued enzymes and nucleic acid will eventually become permanently inactivated/denaturation
Optimum Temperature
Covers a small range, intermediate between the minimum and maximum, which promotes the fastest rate of growth and metabolism
Bacterium that only multiplies in the range of 32-38 degrees
Typhus bacterium
virus that multiplies most successfully in tissues that are slightly below normal body temperatures (33-35 degrees)
rhinoviruses
A microorganism that has an optimum temperature below 15 degrees Celsius and is still capable of growth at 0 degrees Celsius
Psychrophile
Microorganisms that grow slowly in cold but have an optimum temperature between 15-30 degrees Celsius
Psychrotolerant
Organisms that grow at intermediate temperatures (20-40 degrees Celsius)
-> m for medium
Mesophiles
Most human pathogens grow optimally somewhere between 30 and 40 degrees, which corresponds with the average human body temp of ___ degrees Celsius
37 degrees Celsius
some mesophilic bacteria such as Staphylococcus aureus grow optimally between 30 and 40 degrees, but are also __________ psychrotolerant meaning they can survive and multiply slowly at refrigerator temps
Facultatively
A term used in biology that designates an organism as capable of growing under differing sets of conditions
Facultative
Microbes that can survive short exposure to high temperatures but are not normally mesophiles
ie. Bacillus and Clostridium
Thermoduric microbes
A microbe that grows optimally at temperatures greater than 45 degrees
(range of 45-80 degrees)
-live in soil and water associated with volcanic activity, in compost piles, and in habitats directly exposed to the sun
Thermophile
can grow between 80-121 degrees Celsius
Extreme thermophiles
List three destructive metabolic biproducts of oxygen
superoxide ion (O2-) hydrogen peroxide (H2O2) -> toxic to cells and used as a disinfectant hydroxyl radicals (OH-)
Two Step Process by Cells to Avoid Damage from Oxidation and Oxygen Bi-products
Step 1: Enzyme superoxide dismutase converts superoxide to hydrogen peroxide
Step 2:
*because hydrogen peroxide is also toxic to cells it must be degraded
Catalase degrades hydrogen peroxide to water and oxygen
Can use oxygen in their metabolism and possess the enzymes needed to process toxic oxygen products.
Ie. Fungi, protozoa,
Aerobe
An organism that cannot grow without oxygen
Obligate aerobe
Organisms that are harmed by normal atmospheric concentrations of oxygen but require small amount of it in metabolism
Ex: organisms that live in soil or in mammalian hosts (helicobacter pylori)
Microaerophiles
Do not require oxygen for metabolism but use it when it is present.
ie. Staphylococci
Facultative anaerobes
LACK the metabolic enzyme systems for using oxygen in respiration.
Ex: many oral bacteria, intestinal bacteria
Anaerobes
Also lack enzymes for processing toxic oxygen and die in its presence
Obligate anaerobes
Do not utilize oxygen but can survive and grow to a limited extent in its presence; they are not harmed by oxygen.
Ex: clostridial species
Although all microbes require some carbon dioxide in their metabolism, ________ grow best at higher CO2 tension than is normally present in the atmosphere.
Ex: Neisseria (a genus causing gonorrhea and meningitis)
Capnophiles
Majority of organisms are _____ related to pH, and grow between pH 6 and 8.
neutrophiles
Microorganisms that live at pH extremes.
Acidophiles
TRUE OR FALSE:
The majority of microbes live in hypotonic and/or isotonic solutions.
TRUE
Microbes that live in habitats with a high solute concentration
; thrives in high osmotic pressure
Osmophiles
A common type of osmophile that prefers high concentrations of salt.
Halophiles
Some microbial species produce yellow carotenoid pigments to protect against damaging effects of light by absorbing and dismantling toxic oxygen
;UV rays and ionizing rays can also be damaging
Radiation
Deep sea microbes that exist under pressures that range from a few times to over 1000 times the pressure of the atmosphere.
; will rupture when exposed to normal atmospheric pressure
Barophiles
An intimate association between individuals from two species (live in a close partnership); used as a synonym for mutualism
Symbiosis
When organisms live in an obligatory and MUTUALLY beneficial relationship
Mutualism (branch of symbiosis)
In this relationship the member called the commensal receives benefits, while its partner is neither harmed NOR benefited.
Commensalism (branch of symbiosis)
A relationship in which the host organism provides the parasitic microbe with nutrients and habitat, while the host suffers and is harmed.
; Microbes that make humans sick fall in this category.
Parasitism (branch of symbiosis)
An association between free-living species that arises when members of a community compete to live in it.
; in this interaction, one microbe secretes chemical substances into the surrounding environment that inhibit or destroy another microbe in the same habitat.
Antagonism
An interrelationship between two or more free-living organisms that benefits them but is not necessary for their survival
Synergism
The ability of bacteria to regulate their gene expression in response to sensing bacterial density; release of specific chemicals
Quorum sensing
TRUE or FALSE
Biofilms can have a different pH and oxygen condition than the surface of the biofilm.
TRUE
Summarize three ways in which microorganisms function in the presence of differing oxygen conditions.
- Those that use oxygen can detoxify it.
2. Those that can neither use oxygen nor detoxify it. 3. Those that do not use oxygen but CAN detoxify it
Identify three important environment factors (other than temp and oxygen) with which organisms must cope.
Radiation - think yellow carotenoid pigments
Pressure - think Barophiles (need high pressure)
Osmotic Pressure - think osmophiles (need high solute concentration) and halophiles which need high salt concentration
List the essential nutrients for bacteria to survive.
CHONPS Carbon Hydrogen Oxygen Phosphorus Potassium Nitrogen Sulfur Calcium Iron Sodium Chlorine Magnesium
Differ between micro and macro nutrients
Macro: HOC
Ex: Carbon, Oxygen, hydrogen: Large quantities used in cell structure and metabolism.
Micro aka: trace elements: MN-Z
EX) , Manganese, Nickel, Zinc: Used in smaller amounts involved in enzyme function and maintenance of protein structure.
6.3 The parent cell enlarges, duplicates its chromosome, and then starts to pull its cell envelope together in the center of the cell using a band of protein, the cell wall eventually forms a complete septum between the two to be individual cells. Two daughter cells are formed.
Binary fission (bacterial growth process)
Time required for a complete fission cycle; also known as doubling time
Generation time
The average generation time of bacteria
30-60 minutes
Bacteria in biofilms behave and respond very differently than planktonic (free-living) bacteria because
different genes are activated
Lag Phase of bacterial growth
“flat” period on the graph when the population appears not to be growing or is growing at less than the exponential rate.
Exponential Growth Phase of bacterial growth
period of max growth
Stationary growth phase
survival mode in which cells either stop growing or grow very slowly
Death Phase
end pf the cell growth due to lack of nutrition, depletion of environment and accumulation of wastes. Cells begin to die
A description of a state in which bacteria are alive but not metabolizing at an appreciable rate and will not grow when inoculated onto laboratory medium.
Viable nonculturable (VNC)
Actively growing cells are more vulnerable to growth ________ and _________.
inhibition & destruction
Turbidity/Turbidometry
A clear nutrient solution becomes turbid, or cloudy, as microbes grow in it
The greater the turbidity the larger the population size
-If light cannot be shone through very well this indicates HIGH turbidity
An inaccuracy with direct cell count and spectrophotometry is:
there is no distinction between dead and live cells
Coulter counter
electronically scans a fluid as it passes through a tiny pipette; as each cell flows by it is detected on an electronic sensor.
Flow Cytometer
works similar to a coulter counter but also measures cell size and can differentiate between alive and dead cells
-used to differentiate between gram pos and gram neg bacteria
A technique that amplifies segments of DNA for testing. Using denaturation, primers, and heat resistant DNA polymerase, the number can be increased several-million-fold.
Polymerase Chain Reaction (PCR)
