Chapter 7 – Microbial Nutrition, Ecology, Growth – Flashcards
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What is nutrition? |
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A process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities. |
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What do all living things require? |
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C, H, O, P, N, S |
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What else is needed but quantitatively varied based on microbe? |
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K, Ca, Fe, Na, Cl, and Mg. |
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What is an essential nutrient? |
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Any substance that must be provided to an organism |
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What are macronutrients? |
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Required in relatively large qualities. PLay principal roles in cell structure + metabolism. |
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What are micronutrients? |
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Trace elements. Present in smaller amounts and involved in enzyme fxn and maintenance or protein structure. |
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Where do heterotrophs obtain Carbon from? |
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Organic sources. |
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Where do autotrophs obtain Carbon from? |
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Use inorganic CO2 as their carbon source. |
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What is Nitrogen essential for? |
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The production of DNA, RNA, ATP and amino acids. |
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What is the primary Nitrogen source for heterotrophs? |
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Proteins (animal/plant), DNA, RNA, and amino acids. Large. |
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Some bacteria utilize _______ _______ nutrients. |
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inorganic nitrogenous. Medium |
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A small number can transform N2 into a usable compound through nitrogen fixation. T or F? |
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T. |
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What must N2 be converted to before cells can use it? What kind of bond is it held together by? |
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NH3. Triple covalent bond. |
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What is oxygen necessary for? |
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Biomolecule production and ATP synthesis. |
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Most bacteria are aerobic or anaerobic? |
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Anaerobic. |
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What is Hydrogen necesarry for? |
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Maintaining PH. (More H, Acid. Less, Base.) Forming Hydrogen bonds (DNA) Source of energy in redox rxn Production of all biomolecules (carbs, proteins, lipids..) |
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Where can H be obtained from? |
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ANY H containing molecule |
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What is Phosphorus necessary for? |
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production of DNA, RNA, ATP and phospholipids. |
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Where is Phosphorus obtained from? |
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DNA, RNA, ATP, phospholipids. |
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PO3-4 and H3PO4 found in rocks and ocean mineral sources can be used as well. T or F? |
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T. |
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What is Sulfur necessary for? |
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Production of select amino acids, and is vital for tertiary protein structure. |
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How is S obtained? |
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By consuming S-containing organic molecules (amino acids) Also in rock as sulfate. |
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What other elements may a cell need in smaller amounts? How are they obtained? |
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K, Na, Ca, Mg, Fe, Zn. ONLY FOUND IN INORGANIC SOURCES vitamins/minerals. |
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What is a growth factor? |
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Essential Organic Nutrient. An organic compound that cannot be synthesized by an organism and must be provided as a nutrient. |
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More Growth Factors = |
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Longer It Takes to Grow AFTER Innoculation |
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What are the 2 main determinants of of Nutrition types? |
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Sources of Carbon and Energy |
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What do phototrophs do? |
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Microbes that photosynthesize |
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What do chemotrophs do? |
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Microbes that gain energy from chemical compounds. What most bacteria are |
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What is a photoautotroph? |
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Photosynthetic, considered to be primary producers on planet. Ex: Cyanobacteria. |
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What is a Chemoorganic autotroph? |
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Use organic compounds for energy and inorganic compounds as a carbon source. |
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What is a Lithoautotroph? |
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Rely totally on inorganic minerals. |
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What is a methanogen? |
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A lithoautotroph that produces methan from hydrogen gas and carbon dioxide. |
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Are heterotrophs the largest group? |
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Yes |
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The majority of heterotrophs are _________ that derive both carbon and energy from ______ molecules. |
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chemoheterotrophs/organic |
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What is a saprobe? |
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Free-living microorganism that does NOT need a host. |
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What do saprobes feed on primarily? |
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Organic detritus from dead organisms AKA primary decomposers on planet. |
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Do most saprobes have a rigid cell wall? what does this cause? |
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Yes. They release enzymes to digest food particles extracellularly. |
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What is an obligate saprobe? |
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Exist strictly on dead organic matter in soil and water. Ex: Maggot |
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What is a facultative parasite? |
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When a saprobe infects a host, usually when a host is compromised. Opportunistic Pathogen. |
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Do Parasites require a living host? |
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Yes. |
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Where do parasites derive their nutrients from? |
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Cells or tissues of a living host. |
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What are parasites also called? Why? |
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Pathogens - cause damage to tissue or even death. |
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What are the 3 basic classifications of parasites? |
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1.)Ectoparasites - live on the body (ringworm) 2.)Endoparasites - live in organs and tissues. (MOST ARE) 3.)Intracellular Parasites - Live within cells (Viruses) |
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What are obligate parasites? |
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Unable to grow outside of a living host. ALL VIRUSES ARE. |
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What are the critical temperatures for microbes? |
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1.)Minimum temp 2.)maximum temp 3.)optimal temp |
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What is a Psychrophilic microbe? |
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Optimal temp between -5-15 degrees. Cannot grow above 20. Found in frigid ocean waters. |
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What is Psychrotrophic microbe? |
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Optimal temp from 20-30 degrees. Common cause in food spoilage. Found in cool soil and water. |
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What is mesophilic bacteria? MAJORITY OF MEDICALLY IMPORTANT MICROBES. |
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Optimal temp 20-40 degrees. (Human pathogens 30-40) Found in soil, water, plants and animals. |
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Mesophilic bacteria that can withstand short periods of higher temp is... |
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thermoduric. |
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What is thermophilic bacteria? |
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Optimal temperature above 45 degrees. (45-80) Some can survive up to 100 degrees. Found in hot springs, compost heaps and water heaters. |
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_____ is the temp at which most enzymes are destroyed. |
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100 degrees celcius |
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What is hyperthermophilic? |
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Optimal temp = 80-120. Usually Archaea. Found in hydrothermal vents in ocean floor. (Newly discovered can survive up to 130) |
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What is an aeorobe? |
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Can use gaseous oxygen in its metabolism and possesses the enzymes needed to process toxic oxygen products. |
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What is an obligate aeorobe? |
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Cannot grow w/o oxygen |
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What is a facultative aerobe? |
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An aerobe that does not require oxygen for its metabolism and is capable of growth in the absence of it. |
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What is a mircoaerophile? |
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Does not grow at normal atmospheric concentrations of oxygen but requires a small amount of it in metabolism. |
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What is an anaerobe? |
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Lacks the metabolic enzyme systems for using oxygen in respiration. |
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What is an obligate anaerobe? |
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Also lack enzymes for processing toxic oxygen and cannot tolerate any free oxygen in the immediate environment and will die if exposed to it. |
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What is an aerotolerant anearobe? |
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Do not utilize oxygen but can survive and grow to a limited extent in its presence. |
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What is a capnophile? |
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Grow best at higher CO2 levels than are normally present in atmosphere. |
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What PH to neutrophilic bacteria prefer? |
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5-8 |
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What PH do human pathogens prefer? |
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6.5-6.7 |
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Do Neutrophilic bacteria grow well in extremes? |
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No. Inhibits enzyme fxn. |
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What PH do acidophilic bacteria prefer? |
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Grows best at PH below 5.5 EX: Helicobacter |
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What PH do Alkalophilic bacteria prefer? where are they found? |
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Above 8.5. found in alkaline lakes and soils. |
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What osmotic pressure do microbes usually live in? |
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Hypotonic or isotonic |
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What is a facultative halophile? |
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Do not normally live in high salt environments but some can survive up to 20% NaCl ex:Staphylococcus |
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What is an obligate halophile? |
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Requires at least 9% NaCl but optimal is around 25% |
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What is the basis of population growth? |
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Binary fission |
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What is step one of binary fission? |
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Parent cell enlarges and duplicates all its genetic material. |
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Step 2? |
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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. |
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Step 3? |
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New cell wall forms between daughter cells. |
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Step 4? |
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Cells separate or may remain attached forming chains/clusters |
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What is the generation time? |
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The amount of time required for a complete fission cycle. Avg 30-60 mins |
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IS bacterial growth exponential? |
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YES. 2>4>8>16>32>64>128 |
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To calculate the size of a population over time... |
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Nf= (Ni)^2n |
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What do each of these letters stand for? |
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Nf= final number of cells Ni = starting number N = generation growth |
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What produces a growth curve? |
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Data from an entire growth period. |
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What are the 5 phases? |
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1.)Lag 2.)Log/Exponential Phase 3.)Stationary Phase 4.)Death Phase 5.)Phase of Prolonged Decline |
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What happens in the lag phase? |
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The period of slow/no growth. Cells are producing the molecules necessary for growth. |
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What happens in the exponential phase? |
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Period of optimal growth and reproduction. Will continue as long as there are sufficient nutrients and space. |
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What happens in the stationary phase? |
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Cell death balances out cell reproduction. |
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What is cell death caused by? |
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1.)Decreased nutrients 2.)Accumulated wastes 3.)Increased cell density. |
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What happens in the death phase? |
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Death outpaces cell reproduction. Caused by depletion of nutrients. 99% of viable cells die. |
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What is the phase of prolonged decline? |
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The "fitest" cells can survive for months to years on the nutrients released by dying cells. |