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