©THEBRIGHT EXAM STUDY SOLUTIONS 8/23/2024 2:39 PM
MCB 2610 Exam 2 Questions And Correct
Answers.
Macronutrients - answer✔✔carbon, nitrogen, phosphorus, sulfur, oxygen, hydrogen, potassium,
sodium, magnesium, calcium, and iron
Micronutrients - answer✔✔manganese, zinc, cobalt, molybdenum, nickel, copper
All organisms require - answer✔✔Carbon, Hydrogen, Oxygen, and electrons
Autotrophs - answer✔✔Assimilate carbon from inorganic sources
Heterotrophs - answer✔✔Assimilate carbon in preexisting organic form
Phototrophs - answer✔✔Capture light energy to produce ATP
Chemotrophs - answer✔✔Capture energy from oxidation of reduced organic or inorganic
compounds
Organotrophs - answer✔✔Acquire their electrons from organic molecules
Lithotrophs - answer✔✔Acquire their electrons from inorganic sources
Mixotrophs - answer✔✔Some organisms have great metabolic flexibility and alter their
metabolism in response to environmental changes
Nitrogen - answer✔✔amino acids, purines, pyrimidines, some carbohydrates, lipids, enzyme
cofactors
- metabolism of amino acids, nitrates, ammonia
- nitrogen fixation
Phosphorus - answer✔✔nucleic acids, phospholipids, coenzymes, some proteins
- inorganic phosphate
- organic molecules containing a phosphoric group
Sulfur - answer✔✔amino acids, coenzymes
- amino acids cysteine and methonine
,©THEBRIGHT EXAM STUDY SOLUTIONS 8/23/2024 2:39 PM
- sulfate (assimilatory sulfate reduction)
Growth factors - answer✔✔organic compounds that cannot be synthesized by an organism but
are essential for growth
- amino acids
- purines/pyrmidines
- vitamins
Nutrient Concentration - answer✔✔Growth rate depends on amount of nutrients in the
environment
Aerobes - answer✔✔Grow in the presence of oxygen
Obligate aerobes - answer✔✔Require oxygen
Microaerophiles - answer✔✔Grow best when there is less oxygen than normal
Anaerobic - answer✔✔Growth occurs without oxygen
Aerotolerant anaerobes - answer✔✔Aren't harmed by oxygen, but don't use it either.
Obligate anaerobes - answer✔✔Cannot grow when oxygen is present
Facultative anaerobes - answer✔✔Can use oxygen but can also grow in the absence of oxygen
Reactive Oxygen Species - answer✔✔Reduced from oxygen
Strict anaerobic microbes - answer✔✔Lack superoxide dismutase and catalase (protective
enzymes)
Anaerobic workstation - answer✔✔Incubator, work gloves, airlock
GasPak Anaerobic system - answer✔✔Lid, lockscrew, clamp, catalyst chamber, gas generator
envelope, rubber gasket seal, anaerobic indicator strip
pH - answer✔✔Microbes have an optimal rage for growth (acidophiles, neutrophiles,
alkalophiles)
Hypotonic solution - answer✔✔Lower osmotic concentration outside
- cells may burst
Hypertonic - answer✔✔Higher osmotic concentration outside
- membrane shrinks
Halophiles - answer✔✔Grow optimally in the presence of NaCl or other salts
, ©THEBRIGHT EXAM STUDY SOLUTIONS 8/23/2024 2:39 PM
Compatibile solutes - answer✔✔Molecules that can be kept at high internal concentration
Osmotolerant - answer✔✔Can grow over wide ranges of water activity
Temperature - answer✔✔Microbes have different optimal temperature growth ranges
(hyperthermophiles, thermophiles, mesophiles, psychrophiles)
Cardinal growth temperatures - answer✔✔Minimal, maximal, optimal
Psychrophiles - answer✔✔0 - 20
Psychrotrophs - answer✔✔1 - 35
Mesophiles - answer✔✔20 - 45
Thermophiles - answer✔✔55 - 85
Hyperthermophiles - answer✔✔85 - 113
Adaptions of thermophiles - answer✔✔- Protein structure stabilized
- Histone-like proteins stabilize DNA
- Membrane stabilized (linkages)
Culture media - answer✔✔Solid or liquid preparation
Specific medium requirements - answer✔✔Depend on the organism being cultured
Culture media can be classified by - answer✔✔- chemical constituents
- physical nature
- function
Chemical composition - answer✔✔- complex
- defined/synthetic
Peptones - answer✔✔Protein hydrolysates prepared by partial digestion of various protein
sources
Extracts - answer✔✔Aqueous extracts (beef or yeast)
Agar - answer✔✔Sulfated polysaccharide used to solidify liquid media (red algae)
Complex Media - answer✔✔- nutrient broth
- tryptic soy broth
- macconkey agar
