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Micro > Week 11 Exam 4 > Flashcards

Week 11 Exam 4 Flashcards

1
Q

What is the goal of metabolism?

A

Microbial Growth

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2
Q

What is microbial growth?
What causes it?
Where is it observed?

A

Increase in population size of microbes

  • because of binary fission
  • observed in colonies or biofilms
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3
Q

What are the most common nutrients needed for growth?

What do cells NEED

A
  • Carbon, Oxygen, Nitrogen, & Hydrogen

- Need: Carbon, Oxygen, hydrogen(electrons) source

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4
Q

Essential Nutrients

A

required substances for growth

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5
Q

Macroelements / Macronutrients

A

needed in large amounts

-C, O, H, N, S, P

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6
Q

Micronutrients / trace elements

A

required in small amounts

  • K, Ca, Mg, Fe, Cu, Mn, Zn, Ca, Mo, Ni (most metals b/c of enzyme factors)
  • often present in water or media components
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7
Q

Carbon source

- two types of organisms and the types of carbon sources they use

A

-all microorganisms need for growth
- carbon is 50% of dry weight of cells
two types:
-autotrophs: inorganic sources of carbon to make organic compounds (CO2) (plants)
-heterotrophs: catabolize reduced organic molecules from other organisms (proteins, carbs, amino acids, & fatty acids) (humans)

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8
Q

Energy source 2 types

A
  • chemotrophs: acquire energy from redox reactions, inorganic or organic chemicals (aerobic, anaerobic, or fermentation) (humans)
  • phototrophs: acquire energy from light via photosynthesis (plants)
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9
Q

Electron / hydrogen source two types

A
  • organotrophs: heterotrophs acquire electrons from same organic matter that provided carbon source (humans)
  • lithotrophs: (rock eaters) autotrophs acquire hydrogen atoms from inorganic molecules (N2, NO2-, H2S, Fe2+)
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10
Q

Obligate aerobes:

Obligate anaerobes:

A

Obligate aerobes: need oxygen to survive

Obligate anaerobes: die in presence oxygen

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11
Q

Why is oxygen toxic?

A

Reactive Oxygen Species: chemical reactions can produce toxic forms of oxygen that are highly reactive and damage cells

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12
Q

ROS 4 types:

  • Singlet oxygen: produced by
  • Superoxide Radical: caused by & removed by
  • Peroxide Anion: produced by & removed by
  • Hydroxyl Radical: produced by
A
  • Singlet oxygen: produced during aerobic metabolism & light
  • Superoxide Radical: caused by incomplete reduction of 02 in ETC, & it is removed by superoxide dismutase
  • Peroxide Anion: produced by superoxide dismutase (product of antioidize enzyme) & removed by catalase or peroxidase
  • Hydroxyl Radical: produced by toning radiation (sun, UV) & peroxide. Most toxic because of no antioxidant enzyme
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13
Q

How to get rid of ROS

A
  • Singlet oxygen: boosted to a higher level energy source
  • Superoxide Radical: superoxide dismutase
  • Peroxide Anion: catalase or peroxide
  • Hydroxyl Radical: nothing
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14
Q

Oxygen requirements / thioglycollate test

A
  • aerobes: require oxygen
  • anaerobes: de in the presence of oxygen
  • facultative anaerobes: live w/ & w/o oxygen
  • aerotolerant anaerobes: live w/ & w/o oxygen
  • microaerophiles: live in low levels of oxygen
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15
Q

Nitrogen requirements

A
  • makes up 14% of dry weight
  • anabolism will stop w/o nitrogen
    where is nitrogen from?
  • recycling amino acids / nucleotides or breaking down proteins
  • use ammonia NH4+ o reiterate NNO3- from their environment
  • Nitrogen fixing bacteria: reduce nitrogen gas N2 to ammonia NH3
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16
Q

generation time

A

time required for bacterial cell to grow and divide

  • dependent on physical and chemical conditions
  • growth is logarithmic or exponential
17
Q

binary fission

A

-

18
Q

Generation time equations:

  • number of cells in a population
    • for one cell:
    • for more than one cell:
  • number of generations:
  • generation time:
A
  • number of cells in a population
    • for one cell: 2^n (n=number of generations)
    • for more than one cell: original number of cells x 2^n
  • number of generations: log(end cells) - log(beginning cells)/ .301
  • generation time: 60 min x hours / number of generations
19
Q

growth curve stages 4

A
  • lag: cells adjust to environment, make enzymes to break present nutrients
  • log: rapid and exponential growth, susceptible to antimicrobial drugs, nutrients in media are abundant
  • stationary: nutrient level declines, waste products are made, growth slows, some are dying
  • death: more cells are dying than reproducing
20
Q

chemostat

A

continuous culture used to maintain microbial population in a particular growth phase (maintains nutrient level)

21
Q

direct methods of measuring microbial growth

  • microscopic counts:
  • Coulter counts:
  • flow cytometry:
  • viable plate counts:
A
  • microscopic counts:count specific volume by viewing cells under microscope
  • Coulter counts: counts cells as they interrupt electrical current flowing to a detector
  • flow cytometry: record changes in light transmission as cells pass through tube
  • viable plate counts: series of dilutions plated on solid media to count CFU/mL, requires incubation
    - membrane filtration
22
Q

indirect methods of measuring microbial growth

  • turbidity:
  • dry weight:
A
  • turbidity: measures the amount of light that passes through culture (measures cloudiness ) (more light = less turbid / bacteria)
  • dry weight: organisms filtered from media, dried, & weighted (more weight= more bacteria)
23
Q

enzymes two reactions

A

enzymes break or form bonds

  • catabolic reactions: destabilize bonds before it will break
  • anabolic reactions: collide with sufficient energy for bonds to form between them

catalysts/enzymes are essential to increase the likelihood of these reactions

24
Q

enzyme activity & activation energy

A

Enzymes lower activation energy that is needed to carry out a reaction
-activation energy: amount of energy needed to trigger a chemical reaction
Activity of enzyme depends on ability of active site to bind to substrate shape
Shape is determined by proteins structure (Amino acid structure)

25
Q

process of enzymatic activity

A

-

26
Q

Factors influencing enzyme activity

  • temperature:
  • pH:
  • substrate concentration:
A
  • temperature: affects protein folding, could denature protein (after optimal temp. protein unfolding)
  • pH: interfere with hydrogen bonding
  • substrate concentration: increased substrate increases enzyme activity until it reaches saturation point
27
Q

feedback inhibition

A

controls the activity of enzymes in a pathway
-end product inhibits earlier enzyme
-saves the cell energy
REVIEW MORE

28
Q

Enzymatic reactions

A
  • reduction/oxidation

- ATP production & energy storage

29
Q

Oxidation & Reduction reactions

A
  • metabolic reactions involve the making or breaking of chemical bonds and then transfer of electrons
  • Oxidaton-reductoin (redox) reactions: electron transfer reactions
30
Q

OIL RIG

A

Oxidation involves loss reduction involves gain

31
Q

Redox reactions

  • reduction can occur by
  • oxidation can occur by
A 
reduction can occur by
-gain of a electron
-gain a hydrogen atom
oxidation can occur by
-losing an electron
-losing a hydrogen atom
-gaining a oxygen atom
32
Q

electron carriers

A

used to move electrons from one location in the cell to another

  • Nicotinamide adenine dinucleotide (NAD+)
  • Nicotinamide adenine dinucleotide phosphate (NADP+)
  • Flavin adenine dinucleotide (FAD)
33
Q

ATP production & energy storage

A

nutrients store energy in chemical bonds, as the nutrients are degraded, energy is released
-that energy can be stored in high-energy phosphate bonds: ATP

34
Q

ATP generation and 3 ways

A

occurs through phosphorylation: inorganic phosphate added to substrate

  • substrate-level phosphorylation: organic molecules receive a phosphate
  • oxidative phosphorylation: electron movement is used to create ATP
  • photophosphorylation: sunlight is used to make ATP

Micro (8 decks)

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