Microbio quiz 3 Flashcards
What is binary fission?
Chromosomes replicates, Cell elongates, cross walls (septa) form, and cells separate to make 2 daughter cells.
What is generation time?
Time to divide
Growth curve typical order?
Lag phase, Log/exponential phase, Stationary phase, and death/decline phase.
In weird cells: There is prolonged decline phase after death phase
What happens in lag phase?
Cells are acclimating to new environment, recovery
What happens in log/exponential phase?
Nutrients increase, waste decreases, and susceptibility to antibiotics; primary metabolites increase.
What happens in stationary phase?
Death rate = reproduction/division rate; secondary metabolites
What happens in death/decline phase?
Waste increases and nutrients decrease; endospores; persisted cells
What happens in prolonged phase?
“Weird cells”; endospores; hardy cells
What are biofilms?
Groups (aggregation of microbes on surfaces)
What are EPS?
Extracellular polymeric substances that are secreted BOM’s that anchor and protect.
What behavior do biofilms have?
Multicellular behavior
How do biofilms form?
- Reversible attachment of planktonic cells (seconds) - ATTACHMENT
- First colonies become irreversibly attached (seconds, mins)
- Growth and cell division (hours, days) - MICROCOLONIES
- Production of EPS and formation of water channels (hours, days) - EXTRACELLULAR MATRIX / MATURATION
- Attachment of secondary colonizers and dispersion of microbes to new sites (days, months)
What is Quorum sensing?
Gene expression controlled by population growth.
Increased population = Increased concentration of “autoinducers” (chemical secretions)
It signals bacteria to produce beneficial proteins
What is FTM?
Fluid thioglycolate medium
What are obligate aerobes?
They require oxygen for metabolism
- Growth at top
What are obligate anaerobes?
They die in the presence of O2
- Growth at bottom
What are facultative anaerobes?
They prefer O2 but can metabolize without it.
- Growth mainly at top, but also throughout.
What are aerotolerant anaerobes?
Doesn’t use O2, but isn’t killed by O2.
- Growth equally throughout.
What are microaerophiles?
Requires O2 in low conic.
- Growth near top but not directly at top.
What is the metabolic variation for Aerobes and microaerophiles?
They are only aerobic respiration.
What is the metabolic variation for facultative anaerobe?
Aerobic respiration but can ferment.
What is the metabolic variation for obligate anaerobe?
Anaerobic respiration.
What is the metabolic variation for Aerotolerant?
Fermentation.
What are reactive oxygen species (ROSes)?
By-products of aerobic metabolism.
What do reactive oxygen species (ROSes) do?
They disrupt chemical bonds in BOMs (toxic oxygen)
What are the reaction oxygen species?
Singlet Oxygen, Superoxide Anion, Peroxide anion, and Hydroxyl radical.
What do ROS Responses do?
Detoxifying enzymes in aerobic organisms.
What makes up ROS responses?
Superoxide dismutase (SOD) + Catalase + Peroxidase
- These enzymes allow for aerobic organisms
What is minimum range?
No significant growth below freezing. Refrigerator temps; may allow slow growth but very few pathogens. Right below optimum, many bacteria survive, some may grow.
What is optimum range?
Rapid growth of bacteria; same may produce toxins.
- Danger Zone (dangerous growth)
What is maximum range?
Right above optimum is very slow bacterial growth. Temps even higher above optimum destroy most microbes. although lower temps take more time.
What are mesophiles?
They are organisms that grow in a temp of 37*, which is the human temp.
What effects organisms/protein structure?
Temp, pH, & salt
What are fastidious microorganisms?
They are organisms with complicated requirements to survive and reproduce.
What is osmotic pressure?
The pressure of water on membranes.
- Inversely proportional to solute concentration
What is a halophile?
An organism that can survive high salt concentrations; they won’t exhibit plasmolysis.
What is a halotolerant?
They can tolerate high salt concentrations.
What is plasmolysis?
When the water is pushed out of the cytoplasm and shrivels up because of the pressure.
What are proteins produced by?
Ribosomes
What is the function of proteins?
Everything that sounds cool or like work; pretty much everything.
What is the structure of a protein?
Primary, secondary, tertiary and quaternary.
What is the primary structure of a protein?
Sequence of amino acids.
What is the secondary structure of a protein?
Adjacent amino acid backbones interact. H-bonds, electrostatic forces.
Alpha helix (Spring) and beta sheet (Zig-zag).
What is the tertiary structure of a protein?
Interaction between R groups.
- H bonds, electrostatic forces, hydrophobic interactions.
- Disulfide bridges (more common in quaternary)
What is the quaternary structure of a protein?
Multiple peptides interact.
- Similar forces to tertiary.
What is the physical requirement for growth of a protein?
pH, and Temp
What is a -phile?
Requires something; (pressure, temp, pH, etc.)
What is a -troph
Prefers something; (can still survive even if not in preferred environment)
Why is it important to maintain temp?
It affects growth because it damages proteins if temp isn’t perfect or good enough for the protein.
What is a denatured protein?
It lost it’s shape.
- Probably because of temp not being good enough.
What are the importances of pH and Salt?
- Halophiles probably won’t survive if taken out of it’s environment.
- Proteins can have broken bonds if the pH or salt isn’t good enough, which can denature the protein.
- Can affect movement of water (osmotic)
What represents secondary structure?
Beta-plated sheets