Microbiology Exam 2
What is a biofilm?
a thin, slimy film of bacteria that adheres to a surface.
Endospore
a unique type of dormant cell - Members of Bacillus and Clostridium produce - extremely resistant to heat, chemicals, ultraviolet light, boiling water - they can germinate and become a vegetative cell
What is a phagosome?
a vacuole in the cytoplasm of a cell, containing a phagocytosed particle enclosed within a part of the cell membrane.
What is sporulation?
formation of endospores
What are phospholipids composed of?
glycerol, 2 fatty acids, and a phosphate group
The primary pathway used by many organisms to convert glucose to pyruvate is
glycolysis
What is fimbriae?
hairlike appendages that allow for attachment
What are glycoproteins?
proteins with carbohydrate attached - if sugar molecules are bonded
Thermotaxis
response to temperature
What is Extracellular polymeric substance (EPS)
secreted by some bacteria outside of cell wall Types: -Capsule; well organized; firmly attached to wall -Slime; not well organized; loosely attached to wall - Functions: - Adhesion -Nutrient accumulation -Protect against phagocytosis - Protect against stress
Phagocytosis
- Cell eating - Used by protozoa - Pseudopods surround, bring material into phagosome - Phagosome fuses with lysosome -> phagolysosome
Pathogen Focus - Clostridium Botulinum
- Domain: Bacteria; a prokaryote - Endospore-former - Cell Shape: Rods - Motile by peritrichous flagella - Gram positive - Obligate Anaerobic (Don't thrive in O2) - Blocks the release of Acetylcholine
What functions do membrane proteins carry out?
- Selective gates - Sensors of environmental conditions - Fluid mosaic model - helps cells to communicate
what is the importance of having sterols as part of some cell membranes?
- increase membrane strength -helps to provide some rigidity to membranes - Not common in prokaryotic cells - Common in eukaryotic cells
--What is pmf, how is it created, and why is it important for some membrane-associated activities?
- it is proton motive force - generated by an electron transport chain -drives flagella rotation, performs some ATP, active transport
Pinocytosis
- the cell is "drinking" - most common in animal cells - forms endosome, which fuses to lysosomes
Which of the following are reasons an organism might use fermentation?
-A suitable inorganic terminal electron acceptor is not available. -They lack an electron transport chain.
What are characteristics of endospores
-Dehydrated -Not actively metabolizing -Resistant to heat, radiation, acids, and many chemicals
Traits of Archaea
-Don't contain peptidoglycan in the cell wall they contain pseudopeptidoglycan - ether linkages - have histone-like proteins - unique RNA sequences
What does Clostridium botulinum cause?
-Foodborne (Honey or jarring) - can cause muscle weakness or paralyses, nausea, abdominal cramps - One of the most potent toxins know 1ug is lethal - Get treatment within 24hrs (antitoxin) or supportive therapy
What are the different levels of protein structure?
-Hydrogen bonding - Polar groups - Non-polar groups - Covalent bonds - Linear sequences of amino acids
extracellular membrane vesicles
-Produced/released to outside environment by many prokaryotes under some growth conditions - Can contain proteins, lipids, nucleic acids - Plays role in some communications between cells
(EPS) Extracellular polymeric substance function
-Protect against chemical stress - Allow cell to adhere/stick to surface - Protection form certain phagocytic eukaryotic
fastidious
-Very hard to grow - can be cultured on enriched agar media with elevated carbon dioxide
Chemotaxis
Cell movement that occurs in response to chemical stimulus
What are the major groups of culturable of Archaea
1. Methanogens 2. Extreme Halophiles 3. Thermoacidophiles (many archaea are extremeophiles)
How many subunits does a ribosome have?
2 subunits: Large and small - Prokaryote - 30S and 50S - Eukaryote- 40S and 60S
How many spikes are on the surface of the Coronavirus?
74 surface spikes - 20nm long
Chitin
A chemical that provides both toughness and flexibility
What is a Microcolony?
A microscopic colony of cells
Cytoskeleton
A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement - was thought that prokaryotes lacked this but they don't
Mutualism
A relationship between two species in which both species benefit
Cytoskeleton: cell framework
Actin filaments- allow cell movement microtubules- thickest component, made from tubulin Intermediate filaments- provide mechanical support
What is competitive inhibition?
An inhibitor competes with the substrate for binding to the active site. -Example sulfa drug
Methanogens
Archaea that release methane, a greenhouse gas.
Histone proteins are NOT in
Bacteria!!
The inner cortex of endospores are filled with
Calcium ions
What is the chemical structure of an amino acid
Carboxyl group, amino group, hydrogen and a side chain or R group
Electron Transport Chain
Converting energy into ATP
Consider the effect of temperature on enzyme activity. If the temperature is too high, proteins will ________and no longer function.
Denature
What are examples of Biofilm
Dental plaque accumulations in pipes, drains
How can you prevent Clostridium botulinum?
Do not ingest suspects food, especially from swollen can be due to gas production - Alkaline pH foods are more likely to foster this growth (sausages are treated with nitrite salts to prevent growth)
What is non-competitive inhibition?
Doesn't attach to active site, but changes the shape of the enzyme so the substrate doesn't fit as well. - Example Mercury
Pathogen Focus Neisseria Gonorrhoeae
Domain- Bacteria Gram negative Shape: Cocci in pairs -Human body is the only natural habit - a STD
Archaea is closer to bacteria than
Eukaryotes
what are the 3 parts of the flagella
Filament Hook Basal Body
What is dipicolinic acid and where is it found?
Found in endospores; confers heat resistance
Ribosomes
Function- Sites of protein synthesis in cytoplasm Structure- Protein and rRNA
What type of cells have chitin in their walls
Fungal cells
Why do endospores form?
It forms when nutrients where depleted in a cell's environment, or other stresses limit cell growth
How many hours does it take for a vegetative cell to complete sporulation and form a mature endospore
It takes 8 hours
Thermoacidophiles
Live in extremely acidic and high temperature environments
Symbiosis
Living together of 2 dissimilar organisms
What is a Receptor
Membrane protein that binds to specific molecule: allowing cells to sense and adjust to its environment
Is Archaea known to cause disease in humans
No, they don't cause disease
Neisseria gonorrhoeae treatment
Penicillin
what type of cells have cellulose in their walls
Plant cells and Algal cell walls
What is a protein chaperone?
Protein that helps other proteins fold properly
What are ribosomes?
Proteins of a cell which are responsible for the growth and development of a cell - made of rRNA and proteins - Are involved in protein synthesis
What are Exotoxins?
Soluble poisonous protein substance secreted by a microorganism; or released from it after cell lysis - Some exotoxins are enzymes
What are the spikes on the SARS-CoV-2 virion composed of?
Spike (S) protein that is inserted in the lipid bilayer membrane of the virus
What is a sulfa drug?
Synthesizes from sulfanomide. Antimicrobial. - competitive inhibition
what is the prokaryotic nucleoid?
The irregularly shaped region inside the cell where the DNA is concentrated
How do prokaryotic ribosomes differ from eukaryotic ribosomes?
The main difference is how they make their proteins
How do phospholipids interact with water?
The polar heads interact with water; the nonpolar tails do not.
What is a phagolysosome?
The structure that results from the fusion of a phagosome and a lysosome.
What happens to misfolded proteins?
They are degraded into their amino acid subunits, which are then used to make new proteins
What are inclusions?
They are reserve deposits found in both pro- and eukaryotes.
membrane vesicles
They carry processed proteins from the exit face of the Golgi complex to the plasma membrane for incorporation into the plasma membrane itself.
True or False: The spike protein of SARS-CoV-2 is coated in sugar molecules, which disguise it from the immune system
True
peroxisome
Use O2 to break down lipids
what are plasmids
Usually circular, extra-chromosomal DNA strands (smaller than main chromosome) that are not essential in every environment to becterial survival
what is the glycoclayx?
a coating of layer of molecules external to the cell way on a prokaryotic cell
What are proteins composed of?
amino acids
What is a ligand?
any molecule that binds specifically to a receptor site of another molecule
What happens when vesicles fuse with lysosomes
autophagy
Lipoprotein
bonding molecules of fat and protein
What is a polypeptide?
chain of amino acids
What can cause a protein to denature?
changes in pH, salt concentration, temperature
lysosomes
contain degradative enzymes
Chitin and beta-glucans are
in the cell walls of most fungi
What are the two main forms of energy?
kinetic and potential
extreme halophiles (archaea)
live in highly saline environments
What is a slime layer?
loose, water-soluble glycocalyx
What is a capsule?
material surrounding the cell outside the cell wall consisting of polysaccharides or protein. It serves to protect the cell.
Neisseria Gonorrhoeae in men and woman
men- notice it sooner, diffuculty peeing and discharge Woman- The cervix is infected and it can be mild or asymptomatic; can cause infertility - Urethritis - Cervicitis - Salpingitis - Proctitis - Conjunctivitis
Chromosome
nuclear material: (condensed, coiled form called nucleoid) - In prokaryotes, its a single, covalently closed, circular DNA molecule
In addition to glucose, which of the following organic compounds can serve as energy sources for microbes?
polysaccharides, fatty acids, proteins, lipids, disaccharides, monosaccharides
What is endocytosis
process by which the cell takes in materials that are too large to pass through - Occurs mostly in Eukaryotes
Sterol =
steroid molecule with a hydroxyl group attached
As part of cellular respiration, a membrane-bound enzyme called ATP ______________ uses energy from a proton-motive force to add a phosphate group to ADP.
synthase
Prokaryotic Rickettsia
their DNA is similar to Mitochondria
What is the endosymbiotic theory?
theory that eukaryotic organelles such as mitochondria and chloroplasts from ancient free living prokaryotes invaded primitive eukaryotic cells - Mitochondria and chloroplast have 70S ribosomes
Extreme Thermophiles
thrive in very hot environments
What are granules?
• Granules = modified lysosomes of hydrolytic degradative enzymes, NADPH-dependent oxidases & α-defensins