Chap 7 Micro Nutrition and Growth Flashcards
Essential Nutrients
carbon,hydrogen, oxygen,nitrogen, phosphorus(phosphate), and sulfur
-CHONPS
Two categories of essential nutrients
-Macronutrients
-Micronutrients
Macronutrients
-Required in large quantities
-Play role in cell structure and metabolism
-Examples: Carbon, hydrogen and oxygen
Micronutrients/trace elements
-Used in smaller amounts
-Involved in enzyme function and protein structure
-Examples: maganese, sinc and nickel
inorganic nutrient
-An atom or simple molecule that contains a combination of atoms other than carbon and hydrogen
-Metal, salts, gases and water
Organic nutrient
-Contain carbon and hydrogen atoms
-Usually the product of living beings
heterotrophs
-Organism that must obtain it’s nutrients from an organic form (living thing)
Autotroph
-Self feeder
-uses inorganic CO2 as it’s carbon source
-converts CO2 into organic compounds
Nitrogen sources
-Nitrogen gas makes up 79% of the Earth atmosphere
-DNA, RNA, ATP are the primary Nitrogen source for heterotrophs
Oxygen sources
-Free gaseous oxygen (O2) makes up 20% of the atmosphere
Hydrogen sources
-Hydrogen is a major element in all organic and several inorganic compounds
-Critical for maintaining pH, forming hydrogen bonds, and source of free energy in oxidation reduction reactions in respiration
Phosphorus/Phosphate sources
-Main inorganic source of phosphorus is phosphate found in rocks and oceanic mineral deposits
-Key component of nucleic acids and therefore essential to the genetics of cells and viruses
Sulfer sources
-Distributed through the environment in mineral form
-Essential component of some vitamins and amino acids methionine and cysteine
Phototrophs
-Microbes that gain energy from sunlight or visible light rays (photosynthesize)
Chemotrophs
-Microbes that gain energy from chemical compounds
Photoautotrophs
-Photosynthetic autotrophs that capture energy of light rays and transform it into chemical energy that can be used in cell metabolism
The two types of Chemoautotrophs
-Chemoorganic autotrophs and chemolithoautotrophs
Chemoorganic autotrophs
-Use organic compounds for energy and inorganic compounds as a carbon source
Chemolithoautotrophs
-Require neither sunlight nor organic nutrients.
-Rely on inorganic materials
-Remove electrons from inorganic substrates and combines them with carbon dioxide and hydrogen
Methanogens
-A type of chemoorganic autotroph (Archaea) which produces methane (CH4) from hydrogen gas and carbon dioxide
4H2 + CO2 –> CH4 + H2O
Chemoheterotrophs/ what are the two types
-Derive both carbon and energy from organic compounds
-Saprobes
-Parasites
aerobic respiration
-process of cellular respiration that takes place in the presence of oxygen gas to produce energy from food.
Saprobes
-Free-living microbe that feed on organic detritus from dead organisms
Parasite
-Feed on cells or tissues of a living host
Diffusion
-Molecular movement of atoms or molecules moving in a gradient from an area of higher density or concentration to an area of lower density or concentration
-Higher to lower!
Osmosis
Diffusion of water through a selectively permeable membrane
Isotonic
-External environment equal in solute concentration to the cells internal environment
Hypotonic
-Hypo means less
-External solute concentration is lower than the cells internal concentration
-Osmosis direction moves INTO the cell
Hypertonic
-Hyper means more
-External solute concentration higher than inside the cell
-Osmosis direction moves out of the cell
Passive/ simple diffusion
-Movement of particles from high to low concentration without a protein
Active transport
-Uses energy
-Transports nutrients against diffution gradient or same direction but faster than diffusion alone
-Specific membrane proteins(permeases and pumps)
-Specialized pumps carry ions (K+, Na+ and H+) across membrane
Facilitated diffusion
-No energy used.
-Molecule binds to specific receptor in the direction of higher to lower concentration
Carrier mediated transport
-Active transport
-Atoms or molecules pumped into or out of cell by receptors
-Driven by ATP
Group translocation
-Active transport
-Uses ATP
-Molecule moved across membrane and converted to useful substance
Endocytosis
-Active transport
-Uses ATP
-Transport of large particles, cells and liquids by engulfment and vesicle formation
Phagocytosis
-A type of endocytosis that moves solids into cells
Pinocytosis
-A type of endocytosis that moves liquids into cell
Environmental factors that influence microbes
-Heat - cold - gases -acid -radiation
-osmotic pressure - hydrostatic pressure and - other microbes
Range of temps for the growth of a given microbial species
-Minimum temp
-Maximum temp
-Optimum temp
Psychrophiles
-Organisms that have an optimum temp of 15C (59F)
-Growth at 0C (32F)
-Can not grow above 20C (68F)
Psychrotolerant optimum temps 15-30C (59-86F
Mesophiles
-Majority of medically significant organisms
-Individual species can grow 10-50C ( 50-122F)
-Optimum growth 20-40C (68-104F)
-Most human pathogens 30-40 C
Thermoduric microbes / Mesophile
-Microbes survive short exposure to high temps
-Common contaminants of heated or pasteurized foods
Thermophiles
-Grow optimally at temps above 45C (113F)
-Live in soil and water associated with volcanic activity, compost piles, habitats exposed to sun
-General range of growth: 45C-80C (113-176F)
-Extreame thermophiles grow: 80C-121C
Microbes fall into one of the three categories in how it uses oxygen
-Use oxygen and can detoxify it
-Can neither use oxygen nor detoxify it
-Do not use oxygen but can detoxify it
Aerobe (aerobic organism)
-Can use gaseous oxygen in its metabolism
-Possesses enzymes needed to process toxic oxygen products
Obligate aerobic organism
-Cannot grow without oxygen
Facultative anaerobe
-Does not require oxygen for its metabolism
-Capable of growth in absence of oxygen
-Metabolizes by aerobic respiration when oxygen is present
-Adopts anaerobic metabolism (fermentation) when oxygen is absent
Anaerobe (anaerobic organism)
-Lacks the metabolic enzyme systems for using oxygen in respiration
Obligate anaerobes
-cannot tolerate free oxygen and will die in its presence
Live in highly reduced habitats such as deep muds, lakes, oceans, and soil
pH
-the degree of acidity or alkalinity of a solution
-Expressed on a scale from 0 to 14
-Pure water is neutral at pH 7.0
-pH value decreases toward 0, acidity increases
-pH value increases toward 14, alkalinity increases
obligate acidophiles
-Require an acidic environment for growth
-Molds and yeasts tolerate acid and are common spoilage agents of pickled foods
Alkalinophiles
-Live in hot pools and soils that contain high levels of basic minerals
-Bacteria that decompose urine create alkaline conditions
Osmophiles
-Live in habitats with high solute concentration
Halophiles (Obligate Halophiles)
-Require high concentrations of salt for growth (9 to 25% NaCl)
-Have significant modifications to their cell walls and membranes and will lyse in hypotonic habitats
Facultative halophiles
-Resistant to salt, even though they do not normally reside in high-salt environments
Barophiles
-Deep sea microbes that exist in pressures up to 1000 times atmospheric pressure
-strictly adapted to high pressures that they rupture when exposed to normal atmospheric pressure
Protective measures phototrophs and other microbes can use to protect against radiation/light
-Yellow carotenoid pigments absorb and dismantle toxic oxygen
-Some microbes use enzymes to overcome the damaging effects of UV radiation on DNA
Symbiotic and its types
-Organisms live in close nutritional relationships
*Mutualism: both members benefit
*Commensalism: one benefits, other is not harmed
*Parasite is dependent and host is harmed
Nonsymbiotic and it’s types
-Organisms are free living; relationships not required for survival
*Synergism: Members cooperate and share nutrients
*Antagonism: Some members are inhibited or destroyed by others
Biofilms: epitome of synergy
-mixed communities of different kinds of bacteria and other microbes:
-“Pioneer” colonizer initially attaches to a surface
-Other microbes attach to the pioneer or to the polymeric or the polymeric sugar and protein substance secreted by the pioneer
-Monitors growth w/ Quorum sensing
Quorum sensing
-cells are stimulated to release chemicals as the population grows to monitor its size
Binary fission
-How bacterial cells grow and reproduce
-Parent cell enlarges
-Chromosomes are duplicated
-Cell envelope pulls together in the center of the cell to form a septum
-Cell divides into two daughter cells
Generation/ doubling time
-The time required for a complete fission cycle
-Each new fission cycle doubles the population
-As long as the environment remains favorable, the doubling effect can continue at a constant rate
-The length of the generation time is a measure of the growth rate of an organism
The growth curve of bacteria
-Lag phase
-Exponential growth
-Stationary phase
-Death phase
Lag phase in growth curve
-Flat period on the graph when the population appears to not be growing or is growing slower than the exponential rate
Exponential phase (logarithmic or log)
-Period where the curve increases dramatically
-Phase will continue as long as cells have adequate nutrients and favorable enviroment
Stationary growth period
-Population enters survival modes and slows or stops growing.
Death phase in growth curve
-Decline in growth rate caused by depleted nutrients and oxygen.
Turbidometry
-A tube of clear nutrient solution becomes cloudy or turbid as microbes grow in it
-The greater the turbidity, the larger the population size (Lower percentage of light)
-Cells in a sample are counted microscopically
-Utilizes a cytometer calibrated to accept a tiny sample spread over a premeasured grid
Practical importance of growth curve
-Antimicrobial agents rapidly accelerate the death phase
-Microbes in the exponential phase are more vulnerable to these agents than those in the stationary phase
-Actively growing cells are more vulnerable to conditions that disrupt cell metabolism and binary fission
-Growth patterns can correspond with the stages of infection:
-Bacterial shedding during the early and middle stages of infection is more likely to spread it to others
Coulter counter
-Electronically scans a culture as it passes through a tiny pipette
-Each cell is detected and registered on an electronic sensor
Flow cytometer
-Similar to a Coulter counter
-Can measure cell size and differentiate between live and dead cells
Polymerase chain reaction (PCR)
-Quantifies bacteria and other microorganisms in environmental and tissue samples without isolating and culturing them
Tests that measure ATP
-Used in food and pharmaceutical industries
-May be used for rapid quantification of microbes in other environmental samples
