Unit 6 Nutrition And Metabolism Flashcards
Bacterial growth requires
A source of energy and raw materials
Why can bacteria grow inside of us
Because they need environmental conditions similar to the ones in our body
Macronutrients definition
Required in large amounts
Micronutrients
Required in small amounts
What is the most important macronutrients
Water
Growth factor definition
Organic compound essential for bacterial growth but cannot be synthesized by the organism
Exemple growth factors
Vitamins (B complex )
Amino acids
Purines and Pyrimidines ( for production of nucleus acid)
How many amino acids
20
Prototrophs
Microorganism that has the ability to synthesize growth factors
Auxotrophs
Organism that has lost the ability to synthesize growth factors and take they from environment
Are most of the bacteria prototrophs or Auxotrophs
Auxotrophs
Cell cycle
Series of events that takes place in a cell from its formation to its division
Mean generation time
The time it’s takes a population to double in number
Bacterial growth definition
Increase of cell constituents
Microbial growth curve in a closed system
Lag phase
Exponential phase
Stationary phase
Death phase
Lag phase
Preparation for cell division
Exponential phase
Reproduce massively
Stationary phase
Plateau because of nutrient and air limitation and accumulation of toxic compounds
Death
Decline in number of viable cells
Exemple of bacteria able to live in salty environment
Halophiles
Environmental conditions for bacterial growth
Osmotic pressure
Humidity
Temperature
pH
pH
Most of them 7-7,2
Why is temperature important
Too high or too low temperatures can disturb enzym catalyzed reactions
Types of bacteria considering temperature
Psychrophiles
Mesophiles
Thermophiles
Psycrophiles
Cold 5-20, Oceans
Lots of Fatty Acids in the plasma membrane
Mesophils
20-40
Human body
Thermophils
40-80
Obligate aerobes
Always use O2
Always use O2
Aerobes
Facultative anaerobes
With or without but prefer O2
With or without but prefer O2
Facultative anaerobes
Aerotolerant anaerobes
No preference
No preference in O2
Aerotolerant anaerobes
Obligate Anaerobes
Never
Never O2
Obligate anaerobes
Metabolism
Total of all the chemical reactions occurring in the cell
Catabolism is also called
Energetic metabolism
Energetic metabolism is also called
Catabolism
Anabolism is also called
Synthetic metabolism
Synthetic metabolism is also called
Anabolism
Definition anabolism
Creation of big molecules from smaller parts
Needs ATP
Catabolism definition
Breakdown of big molecules into aller ones
Release ATP
Exemple macromolecules
Carbohydrates, Proteins, Lipids, Nucleic acids
Catabolism of macromolecules results in…
simple molecules, electrons and ATP
Autotrophs
Use CO2 as a source of carbon
Heterotrophs get carbon…
from organic sources
Phototrophs get energy from…
Light
… use light as a source of energy
Phototrophs
Chemotrophs use…
Red/ox as a source of energy
… use red/ox as a source of energy
Chemotrophs
Most of the pathogenic bacteria are…
(Source of carbon and energy)
Heterotrophs and Chemotrophs
Catabolism stages
Chemotaxis
Digestion
Absorption
Preparation
Oxidation
Chemotaxis
Detection and approach nutrients
Digestion
Hydrolysis of large molecules via enzymes that are released by bacteria
Ex digestive enzymes
Protease, Peptidase, lipase, sucrase
Absorption
The small molecules produced get into the cytoplasm by active or passive transport mechanisms
Preparation
Complex metabolic pathways where the smaller molecules get degraded a second time
Little bit of energy produced
Oxidation
Complete oxidation forming simple end products
Simple or passive diffusion
Substance passes through the membrane without intermediary
Follows the gradient so doesn’t require energy
Osmosis
Water diffusion
No energy needed
Associated permease transport
Via cytoplasmic membrane proteins
With gradient➡️facilitated diffusion
Against gradient➡️active transport
Difference substances transported by simple diffusion or facilitated diffusion
Simple diffusion transports smaller molecules, non polar/hydrophobic molecules
Group translocation
Molecule changes while entering the cell
Requires energy
Exemple group translocation
Phosphorylation of sucrose
Is water polar or non polar
Polar
Facilitated diffusion
Faster than simple diffusion
Used to transport hydrophilic molecules
Protein that recognizes specific molecules
Name of the protein of facilitated and active transport
Permeases
Two oxidation processes
Respiration: oxidative phosphorylation
Last compound is inorganic
Fermentation :substrate level phosphorylation
Last compound is organic
Aerobic respiration generates 2 toxic oxidizing byproducts for the bacteria…
H2O2 hydrogen peroxyde
O2- superoxide anion
Enzymes that protect from the toxic byproducts
Catalase for hydrogen peroxide
Superoxide dismutase
Two types of respiration
Aerobic
Anaerobic
Which respiration produces the most ATP
Aerobic respiration
Fermentation
Anaerobic
Terminal acceptor is organic
Production of acids
Low energy yield 2ATP/ Glucose
Aerobic respiration
Electron transport chain
Terminal electron acceptor is O2
High energy yield 38ATP/ glucose
Anaerobic respiration
Electron transport chain
Terminal electron acceptor is NOT O2, could be carbon dioxide, nitrate, sulfate
Energy yield medium
In the lab we should reproduce and supply
Optimum growth conditions: T, O2, pH, osmotic pressure
Nutrients
To have optimum growth conditions and supply nutrients we need
Culture media: solid, semi-solid, liquid. Natural, synthetic or semisynthetic
Incubator
What are incubators for
Temperature
Atmosphere: aerobic, anaerobic, microaerophilic, CO2 enrichment
Bacteria that require low level of dioxygen
Microaerophile
Main purposes of cultivation
Grow and isolate microorganisms present in a clinical specimen
Determine which microorganism are most likely causing infections
Obtain sufficient growth to allow identification, characterization and susceptibility testing
Cultivation
Process of growing microorganisms in culture in the artificial environment of the lab by taking them from the infection site
Classification of the media by the physical state
Liquid
Semi solid
Solid
Solid state
Firm surface on which cells can form discrete colonies
Advantageous for isolating and culturing different bacteria and fungi
Observation of colonies
Semi solid
At normal room temperature, clot like consistency
Liquid
Water based solutions that do not solidify at temperatures above freezing
Present a dispersed or cloudy appearance (turbidity)
Synthetic chemical composition
Precise composition
Semisynthetic composition
Partially known
Functional types of media
General purpose
Enriched
Selective
Differential
General purpose media
To grow a broad spectrum of microbes
Enriched media
Contains substances such as blood, plasma, growth factors, etc required for the growth of the bacteria
Selective media
Contains agents that inhibit the growth of certain bacteria
Could be antibiotics
Differential media
Multiple bacteria grow, but show differences, in color for ex
Bacterial colony
Numerous bacterial cells derived from one parent
2 ways of identifying bacteria
Genotyping characteristics
Phenotypic characteristics
Genotyping characteristics
Using molecular techniques for DNA or RNA analysis
Indentification via phenotypic characteristics
Microscopic morphology and staining characteristics
Macroscopic morphology, including odor and color
Environmental requirements for growth
Resistance or suceptibility to microbial agents
Nutritional requirements and metabolic byproducts (waste)
Biochemical tests used in identification of bacteria
Test the presence of enzymes
To demonstrate metabolic pathways
Ability to survive in the presence of inhibitors
Test the presence of enzymes like…
Catalase
Urease
Test for metabolic pathways
Oxidation and fermentation tests
Amino acid degradation
Using a substrate
Two type of diagnostic techniques
Direct (test the bacteria)
Indirect (test the blood)
Direct diagnostic techniques
Microscopy
Culture (selective etc)
Antigen detection
Biochemical tests
Antibiogram
Nucleic acid detection
Proteomic techniques (proteins)
Antibiogram
Testing the resistance of a bacteria to drugs
Immunologic techniques
Antibody and antigen detection
Serology test
Test the presence of antibodies
Molecular techniques
Nucleic acid detection
Respiration is also called
Oxidative phosphorylation
Fermentation is also called
Substrate level phosphorylation
