Microbial Nutrition and Growth Flashcards
What are macronutrients?
a chemical substance required in relatively large quantities and play principal roles in cell structure and metabolism
What are some examples of macronutrients?
Carbon, hydrogen, and oxygen
What are micronutrients?
a chemical substance required in small quantities called ‘trace elements’ and are involved in enzyme function and maintenance of protein strucuture
What are some examples of micronutrients?
manganese, zinc, nickel
What are some characteristics of organic nutrients?
Contain hydrogen and carbon atoms and are products of living things, simple organic molecules, large polymers(carbs, proteins, nucleic acids, lipids)
Where do microbes obtain their nutrients from?
Either solely from inorganic compounds, or a combination of inorganic/organic compounds
What are heterotrophs?
An organism that must obtain its carbon in an organic form and is dependent on other sources
What is an autotroph?
An organism that uses inorganic CO2 into organic compounds and is independent from other living things
What is a phototroph?
Microbes that photosynthesize(use sunlight to feed)
What are chemotrophs?
Microbes that gain energy from chemical compounds
Some examples of Autotrophs are:
photoautotroph, chemoautotroph
Some examples of Heterotrophs are:
Photoheterotroph, chemoheterotroph, saprobe, parasite
What are saprobes?
free-living microorganisms that feed on organic matter from dead organisms
How do parasites get their nutrients?
By deriving nutrients from the tissue and cells of a living host
What are the different types of parasites?
Range from viruses, helminths, ectoparasites, endoparasites, intracellular parasites, and obligate parasites
What is the most extreme type of parasitic invasion?
Intracellular parasites live within cells
What are the vast majority of microbes that cause human disease called?
Chemoheterotrophs
How can less strict parasites can be cultured artificially?
Provided with correct nutrients and environmental conditions
What are obligate parasites?
They are unable to grow outside of a living host(leprosy bacillus and syphilis spirochete)
What are the essential nutrients for microbes?
carbon, hydrogen, oxygen, nitrogen, phosphate, and sulfur
What is passive diffusion?
Movements of atoms and molecules from an area of higher density/concentration to an area of lower density/concentration
What is osmosis?
Diffusion of water through a selective or permeable membrane
What is active transport?
It goes against the diffusion gradient, expends ATP, involved membrane proteins or pumps
What is endocytosis?
a form of active transport where a cell uses energy and forms a vacuole around the substance
What are two types of endocytosis?
Phagocytosis and pinocytosis
What is phagocytosis?
An ‘eating’ method of transport where amoebas and WBCs ingest whole cells or solid matter
What is pinocytosis?
A ‘drinking’ method of transport where liquids(oils, molecules in solution) are ingested
What are cardinal temperatures?
A range of temperatures for the growth of a given microbial species
Optimum temperatures
allows the fastest rate of growth and metabolism
What are some characteristics of psychrophiles?
optimum temp-below 15 degrees C
can grow at 0 degrees C
Storage at refrigerator temp incubates rather than inhibits them
live in rivers/snowfields/polar ice/ deep ocean
rarely pathogenic
What are some characteristics of Psychrotrophs?
grow slow in cold
optimum temp-15 degrees C to 30 degrees C
Staphylococcus aureus and Listeria
can grow at refrigerator temps and cause food-borne disease
What are some characteristics of mesophiles?
Medically important microorganisms
Grow at intermediate temps-20 degrees C and 40 degrees C
inhabit animals and plants, soil and water
What is the optimal temperature of human pathogens?
Between 30 degrees C and 40 degrees C
What are some characteristics of thermoduric?
can survive short exposure to high temps-normally mesophiles
Common contaminants of heated/pasteurized foods
spore formers- Bacillus and Clostridium
What are some characteristics of Thermophile?
Optimum temps- greater than 45 degrees C
live in soil and water associated with volcanic activity, compost piles
range of growth 45 degrees C to 80 degrees C
