Chapter 7 – Microbial Nutrition, Ecology, Growth – Flashcards

Unlock all answers in this set

Unlock answers
question
What is nutrition?
answer
A process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities.
question
What do all living things require?
answer
C, H, O, P, N, S
question
What else is needed but quantitatively varied based on microbe?
answer
K, Ca, Fe, Na, Cl, and Mg.
question
What is an essential nutrient?
answer
Any substance that must be provided to an organism
question
What are macronutrients?
answer
Required in relatively large qualities. PLay principal roles in cell structure + metabolism.
question
What are micronutrients?
answer
Trace elements. Present in smaller amounts and involved in enzyme fxn and maintenance or protein structure.
question
Where do heterotrophs obtain Carbon from?
answer
Organic sources.
question
Where do autotrophs obtain Carbon from?
answer
Use inorganic CO2 as their carbon source.
question
What is Nitrogen essential for?
answer
The production of DNA, RNA, ATP and amino acids.
question
What is the primary Nitrogen source for heterotrophs?
answer
Proteins (animal/plant), DNA, RNA, and amino acids. Large.
question
Some bacteria utilize _______ _______ nutrients.
answer
inorganic nitrogenous. Medium
question
A small number can transform N2 into a usable compound through nitrogen fixation. T or F?
answer
T.
question
What must N2 be converted to before cells can use it? What kind of bond is it held together by?
answer
NH3. Triple covalent bond.
question
What is oxygen necessary for?
answer
Biomolecule production and ATP synthesis.
question
Most bacteria are aerobic or anaerobic?
answer
Anaerobic.
question
What is Hydrogen necesarry for?
answer
Maintaining PH. (More H, Acid. Less, Base.)
Forming Hydrogen bonds (DNA)
Source of energy in redox rxn
Production of all biomolecules (carbs, proteins, lipids..)
question
Where can H be obtained from?
answer
ANY H containing molecule
question
What is Phosphorus necessary for?
answer
production of DNA, RNA, ATP and phospholipids.
question
Where is Phosphorus obtained from?
answer
DNA, RNA, ATP, phospholipids.
question
PO3-4 and H3PO4 found in rocks and ocean mineral sources can be used as well. T or F?
answer
T.
question
What is Sulfur necessary for?
answer
Production of select amino acids, and is vital for tertiary protein structure.
question
How is S obtained?
answer
By consuming S-containing organic molecules (amino acids) Also in rock as sulfate.
question
What other elements may a cell need in smaller amounts? How are they obtained?
answer
K, Na, Ca, Mg, Fe, Zn. ONLY FOUND IN INORGANIC SOURCES vitamins/minerals.
question
What is a growth factor?
answer
Essential Organic Nutrient. An organic compound that cannot be synthesized by an organism and must be provided as a nutrient.
question
More Growth Factors =
answer
Longer It Takes to Grow AFTER Innoculation
question
What are the 2 main determinants of of Nutrition types?
answer
Sources of Carbon and Energy
question
What do phototrophs do?
answer
Microbes that photosynthesize
question
What do chemotrophs do?
answer
Microbes that gain energy from chemical compounds. What most bacteria are
question
What is a photoautotroph?
answer
Photosynthetic, considered to be primary producers on planet. Ex: Cyanobacteria.
question
What is a Chemoorganic autotroph?
answer
Use organic compounds for energy and inorganic compounds as a carbon source.
question
What is a Lithoautotroph?
answer
Rely totally on inorganic minerals.
question
What is a methanogen?
answer
A lithoautotroph that produces methan from hydrogen gas and carbon dioxide.
question
Are heterotrophs the largest group?
answer
Yes
question
The majority of heterotrophs are _________ that derive both carbon and energy from ______ molecules.
answer
chemoheterotrophs/organic
question
What is a saprobe?
answer
Free-living microorganism that does NOT need a host.
question
What do saprobes feed on primarily?
answer
Organic detritus from dead organisms AKA primary decomposers on planet.
question
Do most saprobes have a rigid cell wall? what does this cause?
answer
Yes. They release enzymes to digest food particles extracellularly.
question
What is an obligate saprobe?
answer
Exist strictly on dead organic matter in soil and water. Ex: Maggot
question
What is a facultative parasite?
answer
When a saprobe infects a host, usually when a host is compromised. Opportunistic Pathogen.
question
Do Parasites require a living host?
answer
Yes.
question
Where do parasites derive their nutrients from?
answer
Cells or tissues of a living host.
question
What are parasites also called? Why?
answer
Pathogens - cause damage to tissue or even death.
question
What are the 3 basic classifications of parasites?
answer
1.)Ectoparasites - live on the body (ringworm)
2.)Endoparasites - live in organs and tissues. (MOST ARE)
3.)Intracellular Parasites - Live within cells (Viruses)
question
What are obligate parasites?
answer
Unable to grow outside of a living host. ALL VIRUSES ARE.
question
What are the critical temperatures for microbes?
answer
1.)Minimum temp 2.)maximum temp 3.)optimal temp
question
What is a Psychrophilic microbe?
answer
Optimal temp between -5-15 degrees. Cannot grow above 20. Found in frigid ocean waters.
question
What is Psychrotrophic microbe?
answer
Optimal temp from 20-30 degrees. Common cause in food spoilage. Found in cool soil and water.
question
What is mesophilic bacteria? MAJORITY OF MEDICALLY IMPORTANT MICROBES.
answer
Optimal temp 20-40 degrees. (Human pathogens 30-40) Found in soil, water, plants and animals.
question
Mesophilic bacteria that can withstand short periods of higher temp is...
answer
thermoduric.
question
What is thermophilic bacteria?
answer
Optimal temperature above 45 degrees. (45-80) Some can survive up to 100 degrees. Found in hot springs, compost heaps and water heaters.
question
_____ is the temp at which most enzymes are destroyed.
answer
100 degrees celcius
question
What is hyperthermophilic?
answer
Optimal temp = 80-120. Usually Archaea. Found in hydrothermal vents in ocean floor. (Newly discovered can survive up to 130)
question
What is an aeorobe?
answer
Can use gaseous oxygen in its metabolism and possesses the enzymes needed to process toxic oxygen products.
question
What is an obligate aeorobe?
answer
Cannot grow w/o oxygen
question
What is a facultative aerobe?
answer
An aerobe that does not require oxygen for its metabolism and is capable of growth in the absence of it.
question
What is a mircoaerophile?
answer
Does not grow at normal atmospheric concentrations of oxygen but requires a small amount of it in metabolism.
question
What is an anaerobe?
answer
Lacks the metabolic enzyme systems for using oxygen in respiration.
question
What is an obligate anaerobe?
answer
Also lack enzymes for processing toxic oxygen and cannot tolerate any free oxygen in the immediate environment and will die if exposed to it.
question
What is an aerotolerant anearobe?
answer
Do not utilize oxygen but can survive and grow to a limited extent in its presence.
question
What is a capnophile?
answer
Grow best at higher CO2 levels than are normally present in atmosphere.
question
What PH to neutrophilic bacteria prefer?
answer
5-8
question
What PH do human pathogens prefer?
answer
6.5-6.7
question
Do Neutrophilic bacteria grow well in extremes?
answer
No. Inhibits enzyme fxn.
question
What PH do acidophilic bacteria prefer?
answer
Grows best at PH below 5.5 EX: Helicobacter
question
What PH do Alkalophilic bacteria prefer? where are they found?
answer
Above 8.5. found in alkaline lakes and soils.
question
What osmotic pressure do microbes usually live in?
answer
Hypotonic or isotonic
question
What is a facultative halophile?
answer
Do not normally live in high salt environments but some can survive up to 20% NaCl ex:Staphylococcus
question
What is an obligate halophile?
answer
Requires at least 9% NaCl but optimal is around 25%
question
What is the basis of population growth?
answer
Binary fission
question
What is step one of binary fission?
answer
Parent cell enlarges and duplicates all its genetic material.
question
Step 2?
answer
DNA copies move to opposite ends of parent and attach to a section of cell membrane as it begins to pinch together at the center.
question
Step 3?
answer
New cell wall forms between daughter cells.
question
Step 4?
answer
Cells separate or may remain attached forming chains/clusters
question
What is the generation time?
answer
The amount of time required for a complete fission cycle. Avg 30-60 mins
question
IS bacterial growth exponential?
answer
YES.
2>4>8>16>32>64>128
question
To calculate the size of a population over time...
answer
Nf= (Ni)^2n
question
What do each of these letters stand for?
answer
Nf= final number of cells
Ni = starting number
N = generation growth
question
What produces a growth curve?
answer
Data from an entire growth period.
question
What are the 5 phases?
answer
1.)Lag 2.)Log/Exponential Phase 3.)Stationary Phase 4.)Death Phase 5.)Phase of Prolonged Decline
question
What happens in the lag phase?
answer
The period of slow/no growth. Cells are producing the molecules necessary for growth.
question
What happens in the exponential phase?
answer
Period of optimal growth and reproduction. Will continue as long as there are sufficient nutrients and space.
question
What happens in the stationary phase?
answer
Cell death balances out cell reproduction.
question
What is cell death caused by?
answer
1.)Decreased nutrients
2.)Accumulated wastes
3.)Increased cell density.
question
What happens in the death phase?
answer
Death outpaces cell reproduction. Caused by depletion of nutrients. 99% of viable cells die.
question
What is the phase of prolonged decline?
answer
The "fitest" cells can survive for months to years on the nutrients released by dying cells.
Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New