Life 205 chpt 1-6 – Flashcards
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| What are the living members of the microbial world? (microorganisms) |
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| Bacteria, archaea, protozoa, algae, fungi, and some multicellular parasites. |
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| All surfaces of the human body are populated with characteristic communities of microbiata called _______ _______. |
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| Normal microbiota |
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| Who disproved the idea of spontaneous generation? It took 200 years! |
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| French Chemist Louis Pasteur did. |
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| How did Louis Pasteur disprove spontaneous generation? |
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| He demonstrated that air is filled with microorganisms with his swan neck flask experiments. |
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| How do microorganisms maintain life on earth? |
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| 1. Convert nitrogen gas into a form that plants can use. It's a symbiotic relationship where nitrogen fixing bacteria grow in roots. 2. They replenish oxygen 3. They break down materials that no other living things can (ex. cellulose) |
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| This is the process by which living organisms degrade environmental pollutants. |
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| Bioremediation |
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| disease causing microbes |
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| pathogens |
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| What are some of the benefits of biotechnology? |
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| We can make recombinant proteins for use in the medical field. (insulin) Vaccines genetically engineered plants gene therapy |
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| What are the 3 domains of life? |
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| Bacteria, Archaea, and Eucarya |
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| This type of cell does not contain a membrane bound nucleus or other membrane bound organelles, instead the genetic material resides in the nucleiod. |
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| The prokaryotic cell. |
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| What domains of life have a prokaryotic cell? |
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| Bacteria and Archaea |
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| What makes Archaea and bacteria so different? |
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| Their chemical composition. Ex: Archaea do not have peptidoglycan in their cell walls. |
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| ________ are known for their ability to survive and grow in extreme environments that kill most other living organisms. |
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| Archaea |
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| Algae, fungi, and protozoa are members of the microbial world that fit into the domain of __________. |
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| Eukaryotes |
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| ______ is always capitalized in nomenclature and _________ is not, but both are italicized. |
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| 1. genus 2. species |
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| What are two features that distinguish prokaryotes from eukaryotes? |
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| 1. eukaryotes have a nuclues and other membrane bound organells. Prokaryotes do not. 2. bacteria multiply by binary fission, and usually have a specific shape with a rigid cell wall. |
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| What are the three members of the non-living microbial world? |
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| 1. viruses 2. viroids 3. Prions |
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| Why are viruses not considered living organisms? |
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| Because by definition a living organism must be composed of one or more cells to be alive. |
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| these consist of a nucleic acid packaged within a protein coat. |
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| viruses |
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| These consist of RNA and no protein coat. They cause plant diseases. |
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| Viroids |
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| These are abnormal forms of cellular protein. They are infectious and bind together in brain to form fibrils. |
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| Prions |
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| An extraordinarily resistant dormant cell produced by some bacteria. |
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| An endospore |
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| The movement of a cell toward or away from a certain chemical in the environment. |
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| Chemotaxis |
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| These bacteria have a cell wall characterized by a thin layer of peptidoglycan surrounded by an outer membrane: when gram stained they are pink. |
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| Gram-negative bacteria |
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| Bacteria that have a cell wall characterized by a thick layer of peptidoglycan: when gram stained they are purple. |
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| Gram-positive bacteria |
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| What are 3 reasons for re-emerging old diseases? |
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| 1. world travel 2. parents neglecting to vaccinate 3. increased elderly population and AIDS population. |
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| What do we call a collection of similar species? |
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| genus |
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| What do we call a group of closely related isolates or strains? |
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| species |
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| What is resolution in microscopy? |
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| The ability to distinguish between objects that are very close together. |
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| This type of microscope directs light toward the specimen at an angle so cells appear as bright objects against dark background. |
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| A dark-field microscope. |
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| This microscope amplifies the difference between refractive index of an object and surrounding medium so cells appear darker. |
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| phase-contrast microscope |
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| This type of microscope uses UV light to see specimen that were either tagged with a flourescent dye or naturally flourecse. |
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| Fluorescence microscope |
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| A _______ dye is used to bind negatively charged cellular components: nucleic acids, some proteins, and cell membrane surfaces. |
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| Basic dyes |
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| What type of dyes are positively charged? |
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| Basic dyes |
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| What are some examples of basic dyes? |
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| 1.methylene blue 2. crystal violet 3. safranin 4. malachite green |
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| An ______ dye binds positively charged structures: some proteins, and cytoplasm. |
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| acidic |
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| Acidic dyes are _______ charged. |
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| negatively charged |
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| cells repel this type of stain so the background is colored. |
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| Acidic dye (negatively charged) |
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| These stains differentiates microbes into different categories depending on staining properties. Often utilize 2 or more stains. |
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| Differential stains (ex: Gram stain, acid-fast stain) |
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| What stain is most commonly used for bacteria? |
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| The gram stain |
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| What are the four steps to gram stain? |
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| 1.Crystal violet(primary stain) 2. Gram's iodine: increases affinity of cellular components for dye. 3. Alcohol: Wash -removes crystal violet and grams iodine from gram negative bacteria only. 4. Safranin: counterstain -stains gram negative cells pink |
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| What is the acid fast stain used for? |
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| A small group of organisms that do not readily take up dyes. (Mycobacterium) |
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| The cell wall of these bacteria contains high concentrations of a waxy fatty acid called mycolic acid that prevents uptake of dyes such as those used in gram staining. |
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| Mycobacterium |
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| acid fast staining can be used in clinical procedures to identify these bacteria, due to the fact that they are among a few organisms that actually retain this dye. |
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| Mycobacterium |
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| A gel like layer that surrounds some microbes. It is a protective fxn and also increases an organisms pathogenicity. |
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| A capsule |
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| An example of a capsule stain. |
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| India ink |
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| what is the primary stain in acid fast staining? |
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| carbolfuchsin |
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| What genera of bacteria form endospores? |
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| Bacillus and Clostridium |
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| Do endospores stain with gram stain? |
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| No, they appear as clear smooth objects within stained cells. Malachite green and safranin are often used to make the endospores more visible. |
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| A bacteria with a spherical shape. |
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| coccus |
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| a bacteria with a cylindrical shape |
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| rod |
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| s rod-shaped bacterium is often called a ______. |
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| bacillus |
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| A bacterium that is so short it can easily be mistaken for a coccus is often called a ________________. |
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| coccobacillus |
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| a bacterium shaped like a short, curved rod. |
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| vibrio |
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| A curved rod, long enough to form spirals. |
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| spirillum |
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| a long, helical cell with a flexible cell wall and a unique mechanism of motility. |
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| spirochete |
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| bacteria that vary in shape are called _______. |
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| pleomorphic |
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| Cocci that typically occur in pairs are routinely called ________. |
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| Diplococci |
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| The surface layers of the prokaryotic cell called the ______ ______ consist of the cytoplasmic membrane, cell wall, and if present, the capsule. |
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| cell envelope |
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| the fluid portion of the cytoplasm. |
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| the cytosol |
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| The outer layer of the outer membrane on a gram-negative bacteria is made of _______. |
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| lipopolysaccharide. (LPS) |
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| Although members of bacteria and archaea have the same general structure of their cytoplasmic membranes, how are they different? |
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| The lipid composition is different. In archaea, the lipid tails are connected to glycerol by a different type of linkage and are not fatty acids. |
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| name 3 molecules that pass freely through the lipid bilayer. |
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| 1.water 2. oxygen, carbon dioxide and nitrogen 3. small hydrophobic molecules |
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| In a prokaryote, the two types of active transport are what? |
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| 1. Transport systems that use proton motive force 2. transport systems that use ATP.(called ABC transporters) |
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| What does ABC transport stand for? |
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| ATP Binding Cassette. These systems use specific binding proteins that reside immediately outside of the cytoplasmic membrane to gather and deliver molecules to the respective transport complexes. |
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| A transport process that chemically alters a molecule during its' passage through the cytoplasmic membrane. Typically done by adding a phosphate group. (phosphorylation) |
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| Group translocation |
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| the process of cells actively moving out certain proteins. |
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| secretion |
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| the process of cells actively moving out certain proteins. |
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| secretion |
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| what is a signal sequence? |
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| A characteristic sequence of amino acids bound to a protein destined for secretion in order to let the cell know what needs to be done with it. |
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| why would a cell need to secrete proteins? |
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| There are many fxns of proteins...one example is that of an extracellular enzyme used to break down macromolecules into smaller subunits small enough to enter the cell for use. |
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| The strength of the bacterial wall is due to what? What prevents bacteria from lysing? |
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| the peptidoglycan found only in bacteria |
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| What is peptidoglycan made up of? |
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| an alternating series of two major subunits: N-acetylmuramic acid (NAM) and N-acetylglusamine (NAG) They are covalently joined together to form a glycan chain. Attached to each of the NAM molecules is a tetrapeptide chain.(a string of four amino acids) that play and important role in the strength of peptidoglycan. |
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| What is the difference btwn gram negative and gram positive peptidoglycan chain? |
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| In gram negative bacteria, the tetrapeptide are joined together directly. In gram positive, they are linked together indirectly by a peptide interbridge. |
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| regardless of it's thickness, what is peptidoglycan permeable to? |
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| Sugars, amino acids, and many other substances |
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| this type of bacteria has teichoic acids that may serve as a cation reserve for enzymes outside the cell wall. |
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| The gram positive bacteria. |
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| what connects the glycan chains in peptidoglycan? |
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| tetrapeptide (a string of 4 amino acids)and a peptide interbridge in gram positive cells |
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| What is the outer layer of the gram negative cell composed of? |
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| lipopolysaccharide (LPS) |
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| Why is LPS important from a medical standpoint? |
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| Because it causes a sometimes deadly response in our bodies. They react so strongly that death often results if bacteria with LPS is actively growing inside. |
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| This is considered an endotoxin because of its lethal effect. |
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| LPS (Lipopolysaccharide) |
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| What two parts of LPS are molecularly notable? |
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| 1.Lipid A Anchors the LPS in the lipid bilayer. This is the portion the body identifies as gram negative bacteria. 2. O antigen: portion of LPS directed away from the membrane. Made up of a chain of sugars that make each different species recognizable. |
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| specialized, channel forming proteins in the cell membrane. |
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| Porins |
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| In the gram negative cell, the region btwn the cytoplasmic membrane and the outer membrane is called what? |
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| periplasmic space |
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| the gel like substance that fill the periplasmic space. |
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| periplasm |
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| what happens to proteins exported from the cytoplasmic membrane on a gram negative cell? |
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| They build up in the periplasmic space unless specifically moved across the outer membrane. |
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| Compounds that interfere with the synthesis of peptidoglycan or weaken its structure are useful why? |
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| The peptidoglycan can no longer keep the cell from lysing and it does not effect eukaryotic cells. |
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| why can mycoplasma bacteria survive without a cell wall and even be resistant to penicillin and lysozyme? |
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| Their plasma has sterols in it, making them much stronger than most bacteria. |
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| Why and how does penicillin work on bacteria? |
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| It is an antibiotic that interferes with the peptidoglycan synthesis. It fxns by preventing the cross-linking of adjacent glycan chains. |
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| None of the archaea have peptidoglycan, but they have a similar molecule called _________. |
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| pseudopeptidoglycan |
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| how does the action of penicillin differ from that of lysozyme? |
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| penicillin prevents the peptidoglycan chains from linking, lysozyme breaks down chains that already existed. |
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| a layer on the outside of a bacterial cell that is distinct and gelatinous. |
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| A capsule |
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| A layer on the outside of a bacterial cell that is diffuse and irregular is called a ______ _______. |
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| slime layer |
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| what are most slime layers and capsules made of? |
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| polysaccharides called glycocalyx |
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| What is a biofilm? |
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| A polymer-encased community of microbes |
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| some capsules allow bacteria to adhere to specific surfaces....true or false? |
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| true! |
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| Some ______ allow bacteria to avoid host defense systems that otherwise protect from infection. |
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| capsules allow bacteria to avoid host defense sometimes. |
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| Long protein structures responsible for most types of prokaryotic motility. |
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| flagella- they can give the cell a competitive advantage. |
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| What are the three parts of a flagellum? |
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| 1. Filament 2. hook 3. and basal body |
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| When a cell has flagella over the entire surface of the cell it is called _______. |
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| peritirchous |
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| a polar flagellum is known by its ..... |
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| Single flagellum at the end of the cell. |
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| What is the pattern of travel for most bacteria with flagella in chemotaxis? |
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| They have runs and tumbles, either toward or away from nutrients or toxins. |
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| These are considerable shorter and thinner than flagella but their structure is familiar to flagella. |
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| Pili |
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| What is/are the functions of pili? |
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| 1.they allow cells to attach to specific surfaces.(called fimbriae) 2. help some types of bacteria move on solid media. 3. or as a sex pilus |
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| What do sex pilus do? |
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| hook together bacterial cells for DNA transfer. |
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| What is an example of a bacteria that uses pili? |
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| Strains of E. coli that cause diarrhhea in the small intestine...they would be otherwise flushed out. |
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| Describe a prokaryotic chromosome |
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| It is typically a single or circular double-stranded DNA molecule that contains all genetic info for the cell. |
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| The mass in the cytoplasm that forms a gel-like region. it is known as the _____. |
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| nucleiod |
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| circular, super coiled double-stranded DNA molecules. (generally much smaller than a chromosome.) |
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| A plasmid |
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| What type of ribosomes are found in prokaryotic cells? |
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| 7OS - the higher the S value, the greater the density. |
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| Why is it important to note that the ribosomes in prokaryotes are different than that of eukaryotes? |
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| Medically, you can make antibiotics that will specifically target the prokaryotes ribosomes. |
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| Accumulations of high-molecular-weight polymers synthesized from a nutrient that a cell has in relative excess. |
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| Storage granules |
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| Some aquatic bacteria produce small, rigid protein-bound compartments that provide buoyancy to the cell. What are they called? |
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| Gas vesicles |
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| A unique type of dormant cell produced by members of the genera Bacillus and Clostridium. |
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| Endospores |
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| What are some key facts about endospores? |
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| They can survive for 100 years..maybe longer. They are not easily killed by boiling, and that can later germinate and enter a vegetative state. |
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| Endospore formation is called _____. |
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| sporulation |
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| The site of oxidation of lipids and toxic chemicals in eukaryotes. |
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| peroxisomes |
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| These digest macromolecules in eukaryotes. |
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| lysosomes |
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| The site where macromolecules made in the ER are modified before being transported in vesicles to other locations. |
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| The Golgi apparatus |
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| These are the power houses of the cell in eukaryotes. |
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| mitochondria |
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| The site of synthesis of macromolecules in the eukaryote. |
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| The Rough ER |
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| The site of lipid synthesis and degradation, also calcium ion storage. |
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| The smooth ER |
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| The specific molecule a receptor binds to. (euk) |
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| a ligand |
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| pinocytosis is a type of ______ that forms a small compartment in the cell and closes to digest certain macromolecules. |
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| endocytosis |
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| What are the 3 types of EUK endocytosis? |
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| 1.pinocytosis 2.receptor-mediated endocytosis 3.phagocytosis |
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| The reverse of endocytosis |
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| exocytosis-the cell expels things out of the cell |
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| What is the Euk ribosome? |
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| 80S |
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| The framework for a euk cell |
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| cytoskeleton |
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| What are the 3 proteins that give structure to the cytoskeleton? |
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| 1.microtubules 2.microfilaments 3. intermediate filaments |
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| What do actin filaments (microfilaments) do inside the euk cell? |
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| allow the cytoplasm to move and are key in psuedopod formation in phagocytosis. |
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| What is one purpose of microtubules in the euk cell? |
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| They form the mitotic spindles in mitosis. |
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| The ribosomes in the mitochondria are what type? What did that lead scientists to believe? |
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| They are 70S...like those in bacteria, leading scientists to believe that mitochondria evolved from bacterial cells. |
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| Where are chloroplasts found? |
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| exclusively in plants and alae. |
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| The time it takes for a population to double in number. |
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| The generation time |
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| What is the equation for figuring generation time if the two values are known? |
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| Nt=No*2" where Nt = The # of cells at a given time No= the original # of cells n = The number of divisions those cells have undergone. |
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| Explain why microbial growth refers to populations rather than cell size. |
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| It doesn't matter what the cell size is, microbial growth is defined as an increase in the number of cells in a population. |
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| The mesh -like accumulation of polymers in a biofilm are called what? |
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| EPS (extracellular polymer substances. |
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| What is a planktonic bacteria? |
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| What that is "free floating" |
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| A population descended from a single cell. |
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| A pure culture |
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| a procedure that minimizes the chance of other organisms being accidentally introduced in a culture. |
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| Aseptic techniques |
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| a distinct mass of cells. It takes about 1 million to be seen by the naked eye. |
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| a colony |
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| What is Agar and why is it used for cultures? (agar plate) |
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| Agar is a polysaccharide used to solidify culture media because very few microbes can degrade it. |
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| The most commonly used technique for isolating prokaryotes. What is the goal? |
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| The streak-plate method and the goal is to separate cells enough so that distinct, well-isolated communities will form. |
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| What properties make agar ideal for use in culture media? |
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| 1. few microbes can break it down 2. It stays solid at a wide range of temps. |
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| What is the estimated number of prokaryotes that can actually be grown in a culture? |
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| only 1% |
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| What are the 5 phases of microbial growth? (growth curve) |
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| 1. lag phase 2. log or exponential phase 3. stationary phase 4. death phase 5.phase of prolonged decline (LLSDP) |
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| What is a batch culture? |
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| A culture that is a closed system where nutrients are not added and waste products are not removed. |
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| What is an open system? (continuous culture) |
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| A culture where nutrients are added and waste products removed to allow for continual growth. |
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| What happens during the lag phase? |
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| When a dilute culture is transferred into a different medium, the cells begin synthesizing enzymes required for growth. |
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| What happens in the log or exponential phase? |
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| cells divide at a constant rate. this is when generation time is measured. Later in the log phase, as nutrients run out, cells produce endospores (if they are able) or they prepare for starvation conditions. |
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| Why is the log phase important medically? |
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| because bacteria are most sensitive to antimicrobial medications at this time. |
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| From the commercial standpoint why is the log phase important? |
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| Some of the molecules made by growing cells are valuable. (ex: amino acids can be sold as nutritional supplements) |
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| Small molecules made by cells as they multiply are called what? |
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| primary metabolites |
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| compounds made during the end of the log phase for purposes other than growth. |
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| secondary metabolites |
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| What are the most valuable secondary metabolites? (commercially) |
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| antibiotics |
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| What happens during the stationary phase? |
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| some cells are dying while others are still multiplying. the total number remains fairly constant. They continue producing secondary metabolites. |
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| What occurs in the death phase? |
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| total number of viable cells drops at a steady rate. rate is exponential, but much slower than growth. |
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| what occurs in the phase of prolonged decline? |
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| a fraction of cells usually survive and over time generates successive waves of slightly modified populations, each better equipped to survive than the previous. |
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| What is a chemostat? |
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| A device that continuously drips fresh medium into a broth culture contained in a chamber. (for a continuous culture)With each drop in, a drop is removed. |
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| what is an extremophile? |
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| usually archaea. they survive in very extreme environments. |
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| What are the main environmental factors that influence microbial growth? |
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| temp atmosphere pH water availability |
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| what are the five commonly divided groups based on temp range? |
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| 1.psychrophiles: -5 C and 15 C 2.psychrotrophs: optimum btwn 20 C and 30 C 3.mesophiles: 25-45 C 4.thermophiles: 35-40 C 5.hyperthermophiles: 45-70 C |
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| the refrigerator slows growth of what microbes? |
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| limits growth of mesophiles, but psychrocphiles and psychrotrophs can still grow...it just happens more slowly |
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| these microbes have an absolute requirement for oxygen |
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| Obligate aerobes |
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| These grow whether oxygen is present or not. better with oxygen. |
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| facultative anaerobes |
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| these microbes CANNOT multiply if oxygen is present. |
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| obligate anaerobes |
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| These microbes require small amounts of oxygen(2-10%) higher concentrations inhibit them. |
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| microaerophiles |
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| these microbes are indifferent to oxygen. they can grow in it's presence but do not use it for energy. |
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| aerotolerant anaerobes |
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| What is an ROS? describe it. |
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| A reactive oxygen species. when an organism uses aerobic respiration, harmful derivatives form.(superoxide and hydrogen peroxide) |
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| What do cells use to protect against ROS? |
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| The enzyme superoxide dismutase which converts superoxide to oxygen and hydrogen peroxide. and the enzyme catalase, which convert hydrogen peroxide into oxygen and water. |
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| although they may grow in very different pHs, prokaryotic cells typically maintain an almost nuetral pH within the cell. true or false? |
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| true! |
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| microbes that live and multiply within the range of pH 5 (acidic) to pH 8 (basic)and have a pH 7. |
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| neutrophiles |
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| What is the bacterium that lives in the stomach and causes ulcers? |
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| Helicobacter pylori |
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| microbes that live in pH lower than 5.5 |
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| acidophiles |
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| these microbes grow in pH above 8.5 |
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| alkaliphiles |
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| all microorganisms require water for growth...true or false? |
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| true!! |
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| Why/how do salt and sugar render water unavailable to cells? |
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| They interact with the water molecules rendering them unavailable. |
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| The phenomenon where solute concentration is higher in the medium than the cell and water diffuses out of the cell and causes the cytoplasm to dehydrate and shrink from the cell wall. |
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| plasmolysis |
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| microbes that tolerate high concentrations of salt (up to 10%Nacl) |
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| halotolerant |
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| microbes that require high levels of sodium chloride 3% |
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| Halophiles |
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| Microbes that require 9% sodium chloride |
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| extreme halophiles |
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| what is the fxn of the enzyme catalase? |
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| Catalase breaks down hydrogen peroxide into oxygen and water. |
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| chemical elements that make up cell constituents are called what? |
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| major elements |
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| What are the major elements? |
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| carbon, hydrogen, nitrogen, sulfur, phosphorous, potassium, magnesium, calcium, and iron. |
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| prokaryotes that use organic carbon |
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| heterotrophs (typically medically important) |
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| These use inorganic carbon in the form of carbon dioxide. They are critical in the cycling of carbon in the environment. They convert inorganic carbon to an organic form. |
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| autotrophs |
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| The process of converting inorganic carbon to organic carbon. |
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| carbon fixation |
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| The process of converting nitrogen to ammonia |
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| Nitrogen fixation(only in prokaryotes) |
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| Why is nitrogen fixation essential to life? |
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| Once the nitrogen is incorporated into cellular material, such as amino acids, other organisms can use it! |
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| a compound that has a carbon attached to a hydrogen atom with a covalent bond |
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| organic compound |
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| nutrients that are available at the lowest concentration relative to need.(think choc chips in choc chip cookies) |
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| limiting nutrients |
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| molecules needed by a cell that are found in the environment |
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| a growth factor |
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| bacteria that have complicated nutritional requirements |
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| fastidious |
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| What is an application of fastidious bacteria? |
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| to measure how many vitamins in food products. |
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| organisms that harvest energy from sunlight. |
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| phototrophs |
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| organisms that harvest energy from chemical compunds |
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| chemotrophs |
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| this type of prokaryote uses the energy of sunlight along with carbon dioxide to make organic compounds. (primary producers) |
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| photoautotrophs |
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| Type of prok that use energy of sunlight and carbon from organic compounds. some are facultative |
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| photoheterotrophs |
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| This group of prok use organic cmpds for energy and derive their carbon from CO2. (often live in seemingly inhospitable places) |
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| chemolithoautotrophs |
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| This group of prok use organic cmpds for both energy and carbon. THey are by far the most common group of microorganisms. |
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| chemoorganoheterotrophs |
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| this media contains a variety of nutrients such as meat juices and digested proteins. |
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| complex media |
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| media composed of exact amounts of pure chemicals |
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| chemically defined media |
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| this type of media inhibits the growth of specific species making it easier to isolate the one being sought. |
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| selective media |
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| this type of media contains substances that certain microbes change in a recognizable way. |
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| Differential media |
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| clear zone of hemolysis |
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| beta hemolysis |
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| zone of greenish partial clearing |
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| alpha hemolysis |
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| an enclosed compartment maintained as an aerobic environment |
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| anearobic chamber |
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| this is used to isolate an organism present as only a very small fraction of a mixed population. |
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| an enrichment culture |
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| In the direct microscope count, how many cells must be present in order to count? |
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| at least 10 million per milliter. |
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| an electronic instrument that counts cells in a suspension as they pass single file through a narrow channel. |
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| a coulter counter |
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| this measures light scattered by cells as they pass a laser to count them. |
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| flow cytometer |
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| the coudiness of a microbial suspension |
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| turbidity |
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| What are the three types of direct counts? |
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| 1.Petroff-Hausser counting chamber 2.Membrane filters 3.coulter counter |
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| brief heat treatment that reduces the number of spoilage organisms and detroy |
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| Brief heat treatment that reduces the number of spoilage organisms and kills disease-causing microbes. |
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| pasteurization |
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| Kills microbes |
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| germicide |
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| Prevents the growth of, but does not kill bacteria |
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| bacteriostatic |
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| Disinfectant |
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| a chemical that destroys many microbes |
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| bactericidal |
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| kills bacteria |
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| completely free of all viable microbes |
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| sterile |
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| a chemical that detroys all microbes |
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| sterilant |
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| a disinfectant nontoxic enough to use on skin. |
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| antiseptic |
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| process of inhibiting microbial growth to delay spoilage. |
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| preservation |
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| what is the most common and reliable method used to kill microbes? |
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| heat treatment |
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| when chlorine and other chemicals react with naturally occurring chemicals in the water to form ______ ___ ________. |
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| Disinfection by-products |
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| how is sterilization different from disinfection? |
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| Sterilization is the destruction or removal of all microbes through physical or chemical means. disinfection is the elimination of most or all pathogens on or in a material. With disinfection, some such as endospores may remain. |
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| What types of microorganisms may be more resistant to antimicrobial procedures? |
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| 1.Endospores 2.protozoan cysts, 3. ocysts 4.mycobacterium:(resistant waxy cell wall) |
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| Instruments that come in direct contact with body tissues(needles and scalpels)MUST be sterile. |
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| critical instruments |
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| instruments that come in contact with mucous membranes. |
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| semicritical instruments |
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| these come into contact with unbroken skin and pose little risk for infection. (stethoscpes, countertops) |
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| Non-critical instruments |
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| Boiling for 5 min kills most things, but may leave what? |
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| endospores |
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| today most pasteurization is what kind? |
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| High-temp short-time |
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| ultra pastuerization uses this. |
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| ultra-high temp |
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| this method of sterilization uses steam and pressure to kill microbes |
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| autoclave |
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| this type of heat is less effective that moist heat. |
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| dry heat |
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| these remove microbes from air. |
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| HEPA High-efficiency particulate air |
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| How does ionizing radiation work in sterilization? |
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| It harms cells directly by destroying DNA and damaging cytoplasmic membranes. |
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| What is UV radiation most used for? how does it sterilize? |
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| Used mostly to destoy microbes in the air and drinking water and to disinfect surfaces. It destroys the DNA. |
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| How does high-pressure sterilization work? |
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| Used to decrease the number of microbes in commercial food products. It works by denaturing proteins and altering cell permeability. It does not alter flavor. |
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| What is the difference btwn the mechanism of a depth filter and that of a membrane filter? |
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| the depth filter uses electrical charges to hold the microbes back. |
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| These destroy all microorganisms, endospores, and viruses; 6-10hrs |
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| Sterilants |
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| Destroy vegetative microorganisms, viruses; not endospores; short time periods. |
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| High-level disinfectants |
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| these destroy vegetative bacteria, mycobacteria, fungi, most viruses; not endospores. |
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| intermediate level disinfectants |
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| These destroy vegetative bacteria, fungi, enveloped viruses; NOT ensospores or naked viruses. |
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| Low-level disinfectants |
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| when selecting the appropriate germicidal chemical, what things should you consider? |
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| 1.toxicity to humans 2.activity in presence of organic material 3.compatability with material being treated 4.residue(will it ruin things?) 5.cost and availability 6.storage and stability 7.environmental |
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| What class of germicidal chemicals are used to sterilize instruments? |
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| Aldehydes: also,Formalin is used to vaccine production and to preserve biological specimens. |
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| What class of chemicals are inexpensive, non-toxic and disinfect |
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| What class of chemicals are inexpensive, non-toxic and disinfectant? |
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| alcohols |
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| What class of chemical is used as antiseptics in soaps, lotions, mouthwash, catheters, surgical mesh, and mucous membranes? |
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| Biguanides |
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| What class of chemicals is used to sterilize medical equipment;penetrate hard to reach places, fabric,and heat or moisture sensitive items? |
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| Ethylene oxide gas |
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| What class of chemicals is used to disinfect inanimate objects, surfaces, water and antiseptics? |
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| Halogens (Chlorine and iodine are ex:) |
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| What class of chemicals are usually too toxic to use? |
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| metals (usually used to disinfect burns) |
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| What class of chemicals decomposes quickly, and is used as a disinfectant for drinking and wastewater? |
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| Ozone O3 |
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| What class of chemicals are powerful oxidizers used as sterilants for pkgd juices , milk and are less toxic than ethylene oxide? |
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| Peroxygens (ex: hydrogen peroxide) |
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| What class of chemicals are used to kill most vegetative bacteria, but are not reliable for all virus groups? |
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| Phenolic compounds (active ingredients in lysol) |
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| What class of chemicals are non-toxic, and are used on food prep surfaces? |
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| Quaternary ammonium compounds |
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| Why is it important to dilute iodine solutions as per recommendation? |
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| because diltion effects the amount of free iodine available. |
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| What are some examples of chemical preservatives? How do they work? |
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| Weak organic acids(benzoic, sorbic, propionic) They inhibit metabolism, alter the cell membrane function and control mold in foods and cosmetics. |
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| What |
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| What are chemicals that can be added to processed meats to inhibit endospore germination, vegetative growth? |
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| Nitrate:it is carcinogenic and gives meat it's pink color |
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| How is preservation of perishable products done best? |
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| Reduce the available water |
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| What are some methods of food preservation? |
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| 1.salting, adding sugar, drying foods (this causes plasmolysis) 2.Lyophilization(freeze drying) 3.Drying (stops microbial growth, does not kill salmonella on outside of eggs) |
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| what is the most important function of nitrate in cured meat? |
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| Most important fxn to inhibit germination of endospores and subsequent growth. |
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| The D value is the amount of time it takes to kill what percent of bacteria? |
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| 90% in the population |
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| a metabolic process that stops short of oxidizing glucose or other organic compounds completely, using an organic intermediate as a terminal electron acceptor. |
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| Fermentation |
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| The sum total of all chemical reactions in the cell. |
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| metabolism |
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| metabolic intermediates that can either be used to make the subunits of macromolecules or oxidized to generate ATP. |
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| Precursor metabolites |
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| Organisms that harvest the energy of sunlight, using it to power the synthesis of organic compounds from CO2. |
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| photosynthetic organisms |
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| These organisms obtain energy by degrading organic cmpds. |
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| chemoorganotrophs |
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| chemical reactions that release energy |
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| exergonic |
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| chemical reactions that require the input of energy. |
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| endergonic |
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| the series of sequential chemical reactions that converts a starting compound to an end product. |
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| A metabolic pathway |
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| The energy it takes to start a reaction. |
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| activation energy |
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| _______ are proteins that accelerate the conversion of the ______ into another product. |
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| 1.enzymes 2.substrate |
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| What does ATP stand for? |
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| andenosione triphosphate |
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| This molecule is composed of ribose, adenine, and three phosphate groups arranged in tandem. |
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| ATP |
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| What is ADP? |
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| adenosine diphosphate |
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| metabolic pathway where energy released in an exergonic rxnis used to power the addition of Pi to ADP. |
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| substrate-level phoshporylation |
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| The energy of proton motive force drives the reaction in this pthway. |
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| oxidative phosphorylation |
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| When electrons move from a molecule with low electron affinity to a molecule with high electron affinity, what is released? |
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| energy |
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| The chemical that serves as the electron donor is what? |
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| The energy source |
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| The chemical that ultimately accepts the electron is called what? |
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| terminal electron acceptor |
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| the substance that loses electrons is ______ |
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| oxidized |
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| the substance that gains electrons is ________. |
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| reduced |
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| cells remove electrons from the energy source through a series of _______ reactions. |
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| redox (oxidation-reduction reactions) |
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| What are the electron carriers? |
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| 1.NAD+/NADH 2.NADP+ / NADPH 3. FAD/ FADH2 |
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| why can electron carriers also be considered hydrogen carriers? |
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| Because along with electrons, they carry protons |
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| What are the central metabolic pathways? (in Porkaryotes) |
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| 1.Glycolysis 2.Pentose phosphate pathway 3. tricarboxylic acid cycle (TCA cycle) |
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| ______ transfers the electrons extracted from glucose to the electron transport chain. |
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| Respiration |
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| organisms that use respiration either aerobic or anaerobic are said to ______. |
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| respire |
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| in this process, cells break down glucose through glycolysis only and then use pyruvate or a derivative as a terminal electron acceptor. It yields relatively little ATP. |
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| fermentation |
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| How does the fate of electrons carried by NADPH differ from the fate of Electrons carried by NADH? |
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| NADH transport electrons to the electron transport chain, the e- carried by NADPH are used to reduce compounds during biosynthetic rxns. |
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| a non-protein component that assist enzymes. (Usually trace elements) |
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| cofactor |
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| organic cofactors that fxn as loosely bound carriers of molecules or electrons. (FAD, NAD+, NADP+) |
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| Coenzymes |
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| These are usually derivatives of vitamins |
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| coenzymes |
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| Enzymes that can be controlled using other molecules that reversibly bind to and distort them. |
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| allosteric (Allosteric regulation) |
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| How does allosteric inhibition work? |
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| the enzyme has an active site as well as an allosteric site. When activity needs to be regulated, the allosteric inhibitor binds to the allosteric site, the enzyme changes shape, and the substrate cannot attach to the active site. |
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| in this, the inhibitor binds to the active site of the enzyme, blocking access of the substrate to that site. |
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| Competitive inhibition |
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| What is an example of competitive inhibition in bacteria? |
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| Antimicrobial medication called sulfa drugs inhibit an enzyme in the pathway bacteria use to synthesize folic acid. leading to death of bacteria. |
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| When the inhibitor binds to a site other than the active site to change the shape of the enzyme so the substrate cannot bind to it. |
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| Non-competitive inhibition |
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| Explain the fxn of coenzymes. |
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| The transfer of substances from one compound to another. |
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| For each molecule of glucose that enters the glycolysis pathway, how many pyruvates are produced |
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| Two molecules of pyruvate. |
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| What does glycolysis generate? |
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| -2 ATP by substrate level phosphorylation - 2 NADH + 2H+ - six diff precursor metabolites |
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| WHat two phases are in glycolysis? |
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| 1. the investment/prep phase 2. the payoff phase |
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| Which central metabolic pathway yields the most reducing power? |
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| The TCA cycle |
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| What is the primary role of the Pentose phosphate pathway? |
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| Production of precursor metabolites, and NADPH |
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| What is the transition step? Where is it used? |
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| Link btwn glycolysis and the TCA cycle. Used in aerobic and anaerobic respiration |
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| What is the yield of the transition step? |
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| -2 NADH=6ATP (from Oxidative phosphsorylation) -2 acetyl CoA |
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| What is the yield of the TCA per 1 molecule of glucose? |
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| -2 ATP (1 per turn) - 6 NADH (3 per turn)= 18 ATP through oxidative phoshorylation - 2 FAD2 = 4 ATP (through OP) - 2 diff precursor molecules |
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| What is the process by which the cell uses the NADH and FADH2 generated during glycolysis, the transition step, and the TCA cycle is called? |
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| Oxidative phosphorylation |
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| What is the diff btwn where prokaryotes and euka pump their protons in the ETC? |
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| Euk pump them into the inter-membrane space of the mitochondria, Pro pump them out of the plasma membrane. |
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| What is the energy of the electrochemical gradient called? |
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| Proton motive force |
