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Microbiology PMY 3 > Module 2-week 5 Bacterial Nutrition And Metabolism Part A > Flashcards

Module 2-week 5 Bacterial Nutrition And Metabolism Part A Flashcards

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1
Q

What are essential nutrients?

A

MacroNutrients and macroelements

  • These are required in large quantities
  • Play principle roles in cell structure and metabolism
  • Availability of essential nutrients and elements impacts microbes ability to grow
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2
Q

List the bacterial macroelements

A

Carbon

Oxygen

Nitrogen

Hydrogen

Phosphorus

Sulfur

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3
Q

Microbes are classified based on their ___________ ________

A

Carbon source

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4
Q

What are heterotrophs?

A

Organisms that obtain carbon from organic matter

  • Most common source-sugars I.e. glucose
  • Most bacteria fall in this category
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5
Q

What are autotrophs?

A

Obtain carbon from inorganic C or CO2

 -Ability to convert CO2 -> Organic compounds
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6
Q

Differentiate aerobic and anaerobic microbes

A

Microbes have variability to grow in the presence of gas O2(aerobic) or absence of O2 gas(anaerobic)

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7
Q

Describe the variable states of Oxygen

A

Oxygen is in variable states that can range from biologically usable to toxic to the cell

-Can originate from inorganic (NO2/O2) or organic (glucose) molecules

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8
Q

Give a general description of usage of oxygen

A

Used in proteins, carbohydrates, lipids and nucleic acids and important respiration

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9
Q

How is nitrogen usually supplied?

A

Usually supplied via inorganic molecule

NH3(ammonia), NO3(nitrate), NO2(nitrite) N2(gas)

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10
Q

What is nitrogen fixation?

A

Some soil microbes obtain N2 gas and convert it to other forms via nitrogen fixation

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11
Q

How do GI microbes obtain NO3 from our food and convert it to NH3?

A

Some GI microbes obtain NO3from our food and convert it to MH3

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12
Q

What molecules is nitrogen used in?

A

All amino acids/ proteins, DNA, RNA , ATP

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13
Q

What is hydrogen used in?

A

Used in REDOX reactions, buffer of pH, hydrogen bonding

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14
Q

What is the use of phosphorus(phosphates) ias an essential nutrients?

A

Used in nucleic acids, ATP, Buffer of pH

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15
Q

What is the use of Sulfur as an essential nutrient?

A

Used in some amino acids(cysteine, methionine), some vitamins, protein stability and shape

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16
Q

What are the sources of hydrogen?

A

Organic sources: glucose

Inorganic: H2O, H3PO4, H2S , CH4, H2

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17
Q

What are the sources of phosphorus(phosphates)?

A

Inorganic sources PO4 ^-3 from H3PO4

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18
Q

What are the sources of sulphur?

A

Inorganic: SO4^-2, FeS, H2S, elemental S

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19
Q

How are macronutrients acquired?

A

Can be acquired externally , synthesized by the cell or reassembled to create new large molecules, possibly from monomers

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20
Q

What are photo autotrophs?

A

Can use sunlight as energy source and CO2 as carbon source via the process of photosynthesis

CO2+ H2O ——> (CH2O)n + O2

E.g. plants, algae, Cyanobacteria

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21
Q

What are chemo-autotrophs?

A

Can use INORGANIC MOLECULES as energy source and CO2 as carbon source via the process of METHANOGENESIS

4H2 + CO2 —> CH4 + 2H2O

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22
Q

Give examples of methane gen’s

A

Methanosarcina, methanobacterium

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23
Q

What are photo-heterotrophs?

A

Use light as energy source and ORGANIC COMPOUNDS as carbon source via the modified process of photosynthesis

E.g. purple non-sulfur bacteria, heliobacteria

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24
Q

What are chemo-heterotrophs?

A

Organisms use ORGANIC COMPOUNDS as energy + carbon source via the process of RESPIRATION or FERMENTATION

E.g. most bacteria

[(CH2O)n] + O2 —> CO2 + H2O + ATP

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25
Q

What is catabolism?

A

The process of generating energy and substrates which are used in anabolism

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26
Q

What is anabolism ?

A

The use of energy and substrates for subsequent biosynthetic pathways

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27
Q

What is metabolism?

A

The net sum of energy transfer between catabolism and anabolism. If enough energy anabolic processes, cell can grow and replicate

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28
Q

How are relationships between microbes beneficial ?

A

Phototrophs produce oxygen which is needed by chemoheterotrophs

Chemotrophs produce Carbon dioxide and water which are needed by photoautotrophs

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29
Q

How is ATP used in metabolism?

A

Adenosine Tri-phosphate: energy is stored in high energy bonds between phosphate groups with catabolism.

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30
Q

How is ADP used in metabolism?

A

Energy is released with loss of a phosphate group and the energy is used in anabolism

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31
Q

What is the purpose of NAD/NADH?

A

Nicotinamide Adenine Dinucleotide/Hydrogen- serves as a co-enzyme Cartier molecule to shuttle electrons during metabolism

A diff usable electron carrier

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32
Q

What is energy currency?

A

biochemical energy is stored and transferred from catabolism to anabolism via ATP, NADH, NADPH

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33
Q

How are macronutrients used in catabolism?

A

Carbs, fats and proteins (Energy yielding products)

Catabolism which is exergonic and produces Chemical energy, ATP, NADH/NADPH

carbs, fats and proteins are converted to energy poor products( CO2, H2O, NH3)

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34
Q

How molecules used for anabolism?

A

Precursor molecules ( amino acids, sugars, fatty acids, nitrogenous bases)

Anabolism is endergonic and uses ATP, NADH/NADPH to synthesize complex molecules( proteins, lipids, nucleic acids and polysaccharides)

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35
Q

Where does glycolysis occur?

A

In the cytoplasm of both eukaryotes and prokaryotes and is independent of oxygen

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36
Q

What is the net output of glycolysis?

A

2 ATP, 2 NADH and 2 pyruvate( pyruvjc acid)

37
Q

What is the first step of Glucose catabolism?

A

Glycolysis- During the first step of glucose catabolism, Glucose-6-Carbon gets broken down to 2x molecules of Pyruvate 3-carbon

38
Q

What 2 different pathways can microbes break down glucose(both forms of glycolysis)?

A

The Embden-Meyerhoff-Parnas(EMP)-both eukaryotes and prokaryotes

Entner-Duodoroff(ED)

39
Q

What are the net end products of EMP?

A

2 ATP

2 NADH

2 pyruvate

40
Q

What are the net end products of enter-duodoroff-ED?

A

1 ATP

1 NADPH

1 NADH

2 Pyruvate

41
Q

When do bacteria usually perform fermentation?

A
  • Occurs in absence in oxygen

- Less efficient than aerobic or anaerobic respiration(2 ATP)

42
Q

When do bacteria perform aerobic respiration?

A
  • Occurs in presence of oxygen
  • Oxygen is a preferred terminal electron acceptor
  • Lots of ATP produced(38 ATP)
43
Q

When do bacteria undergo anaerobic respiration?

A
  • Occurs in absence of oxygen
  • Use of an alternative electron acceptor
  • Less efficient than aerobic (5-30 ATP)
44
Q

How does oxygen presence effect efficient of glucose metabolism?

A

In the presence of Oxygen, glucose metabolism is much more energy efficient than fermentation due to the Kreb’s cycle and ETC

45
Q

What is the net total output of aerobic respiration?

A

6CO2 + 6H2O + 36/38 ATP

46
Q

What is the function of Oxygen in aerobic respiration?

A

Oxygen acts as a Terminal electron acceptor in the ETC of the electrons from NADH and FADH, which generates ATP energy

47
Q

What happens to pyruvate, NADH and FADH2 in aerobic respiration?

A
  • Pyruvate is completely oxidized via intermediate step and Kreb’s cycle
  • NADH and FADH2 are reduced via glycolysis and Kreb’s cycle and are then associate with the Electron Transport
48
Q

Summarize the steps in aerobic respiration

A
  1. Glycolysis
  2. Pyruvate metabolism
  3. Kreb’s cycle
  4. Chemiosmosis and electron transport chain
49
Q

Where does the Kreb’s cycle/TCA cycle/ Citruc acid cycle occur ?

A

Occurs in cytoplasm in prokaryotes

Occurs in mitochondria in eukaryotes

50
Q

What is the net output of the Kreb’s cycle?

A

6CO2+ 2ATP+ 2FADH2 + 8NADH

51
Q

What are the goals of the Kreb’s cycle?

A
  • main goal is the oxidation of pyruvic acid.
  • Efficient transfer of electrons from carbon molecules to reduce coenzyme electron carriers NADH and FADH
  • Important for production of amino acid intermediates
52
Q

What are the goals of the Electron Transport Chain?

A
  • Goal is oxidation of NADH and FADH via transfer of electrons to the Electron Transfer Chain
  • The process is coupled with ATP synthase to generate ATP
  • Important for production ATP and recycling co-enzymes
53
Q

Where is the electron transport chain?

A

In the cell membrane in prokaryotes

In the mitochondria in eukaryotes

54
Q

What type of phosphorylation occurs in the electron transport chain?

A

Produces 32 ATP (ETC) via oxidative phosphorylation

55
Q

Summarize the events of the ETC

A
  • NADH donates electrons and is oxidized back to NAD+
  • Oxygen accepts electrons and is reduced to H2O( Nitrate can serve as electron acceptor for anaerobic respiration)
  • Energy from the electron shuttling is captured in ATP
56
Q

What are some applications of anaerobic respiration?

A

Relevant in nitrogen cycling and diagnostics

 E.x. Nitrite in urine indicates infection
57
Q

What are the goals of anaerobic respiration?

A

Goal is oxidation of NADH in pathways that serve as electron shuttle mechanism and occurs in cell membrane in prokaryotes

Anaerobic respiration can recycle the co-enzymes needed for glycolysis

58
Q

Describe Anaerobic respiration

A

In the absence of oxygen as terminal electron acceptor, bacteria can use an alternative inorganic electron acceptor ex. NO3

59
Q

Why does fermentation have a very low yield of energy?

A

Has a very low yield of energy (2 ATP) per glucose as it comes from glycolysis ONLY and occurs in the absence of oxygen

60
Q

What are the applications of fermentation?

A

Fermentation by-products from Pyruvate are important for:

-Industry
Cheese, pickles, yogurt, alcohol, chocolate,souring milk
Industrial agents

  • human health
    Maintaining homeostasis

-Diagnostics
Lab tests

61
Q

What happens to pyruvate in the absence of oxygen?

A

Pyruvate is concerted to lactic acid/lactate

This produces the oxidation of NADH —> NAD+

62
Q

What are some bacteria which undergo fermentation?

A

Streptococcus and lactobacillus sp.

63
Q

What are some uses of fermentation to produce industrial reagents ?

A

Butyric acid (Butanol) fermentation by Clostridium sp.

Pyruvate —> variety of products

Includes:
Acetone+ CO2

Isopropanol + CO2

Butyrate

Butanol

Used for production of commercial organic solvents

64
Q

How does fermentation contribute to human health?

A
  • Consumption of fermented products is beneficial to a variety of health conditions and promotes diversity of the GI microbiota
  • Normal flora maintain low pH to inhibit growth of pathogens
65
Q

How is fermentation used in diagnostics ?

A

Methyl Red test

  • tests availability to ferment glucose to variety of fermentation acids
  • Addition of methyl red pH indicator results in color change due to acidity of broth from acid production
  • # 1 yellow is negative (Enterobacter)
  • # 2 red is positive E. coli
66
Q

What are the meanings of yellow and red in the methyl red test?

A
  • # 1 yellow is negative (Enterobacter)

- #2 red is positive( E. coli)

67
Q

Energy metabolism is another term for…

A

Catabolism

68
Q

Biosynthetic metabolism is another term for…

A

Anabolism

69
Q

What do we need for biosynthesis?

A

-convert organic molecules and ATP into the “building blocks”(precursor monomers for macronutrients), which are required for cell growth and replication

70
Q

What are sugars used to produce in biosynthesis?

A

Polysaccharides

71
Q

What are amino acids used to produce in biosynthesis?

A

Complex proteins

72
Q

What are nucleic acids used to produce in biosynthesis?

A

DNA, RNA

73
Q

What are lipids used to produce in biosynthesis?

A

Lipid belayer of membrane

74
Q

How are sugars converted to complex sugars?

A

Intermediate products of glycolysis are converted to complex sugars at the expense of ATP

Glucose 6-phosphate —> ADPG —> glycogen(in bacteria) (ATP required)

Glucose 6-phosphate —> UDPG —> glycogen (in animals)(UTP required)

Fructose 6-phosphate —> UDPNAc —> peptidoglycan (in bacteria)(UTP required)

75
Q

What is the biosynthesis process of amino acids

A

Intermediates of lentos pathway, Kreb’s cycle and ED are converted to amino acids for protein synthesis

This is done via a inaction or transamination

76
Q

Briefly describe the biosynthesis of nucleic acids

A

Intermediate products of glycolysis, pentose pathway, Kreb’s cycle and ED are converted to nucleic acids for DNA synthesis

77
Q

Briefly describe the biosynthesis of lipids

A

Intermediate product of Glycolysis and Kreb’s cycle are converted to simple lipids for complex lipid synthesis

78
Q

What are the 4 processes involved in binary fission?

A
  • Requires anabolic process for building blocks
  • DNA replication
  • Increase in cell size (cell elongation)
  • Cell division by cleaving of cell membrane and wall
79
Q

Describe the bacterial growth rate

A

Growth is exponential and measured in log10(best for graphing)

One bacterial cell of E. coli with a population-doubling time of 20 minutes

  • will give rise to 10 million cells within 8 hours
    - 10,000,000- 10^7
80
Q

Describe the kinetics of bacterial reproduction

A
  • Binary fission results in doubling of viable cell number

- Cell count is predicted as Log2 over time

81
Q

What is Generation/ doubling time(g)?

A

Time required for a complete fission replication cycle which varies between organisms, depending on conditions

82
Q

What are each of the axis in a logarithmic plot ?

A

Logarithmic plots are preferred with X-axis scale of generations over time (could be minutes hours or days )

Y-axis scale of Log10

83
Q

When are the most accurate cell numbers recorded in bacterial growth?

A

Most accurate cell numbers recorded during early growth

84
Q

What are the conditions under which a growth curve is made?

A

In a closed system: nutrients and space are finite no removal of waste products

85
Q

What are the phases of a growth curve?

A
  1. Stationary phase
  2. Exponential (log) phase
  3. Stationary phase
  4. Death phase
86
Q

Explain the lag phase of bacterial growth

A
  • Newly inoculated cells, adjust to new environment
  • Cells not multiplying at maximum rate
  • Population is sparse or dilute
87
Q

What is the exponential (log) phase of bacterial growth dynamics?

A
  • Growth occurs at an exponential rate
  • Cells reach maximum rate of cell division
  • Continues as long as nutrients and environment are favorable
88
Q

What is the stationary phase of bacterial growth dynamics?

A
  • Population reaches maximum numbers

- Rate of cell inhibition or death= rate of multiplication

89
Q

What is the death phase of bacterial growth phase?

A
  • Decline in growth rate
  • Caused by depletion of nutrients, O2Excretion of toxic waste products
    Increased density of cells (limited space)

Microbiology PMY 3 (24 decks)

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