Unit two: ch. 5-9 *skipped ch. 7

Name six methods of physical control of microorganisms.

1. heat 2. cold 3. desiccation 4. radiation 5. filtration 6. osmotic pressure

Explain two methods of dry heat control. Table 9.6

1. incineration: 2. hot air oven:

List the three principal purposes of cultivating viruses.

1. isolate and identify viruses in clinical specimen. 2. prepare viruses for vaccines. 3.do detailed research on viral structure, multiplication cycles, genetics, and effects on host cells

Compare and contrast the four phases of growth in a bacterial growth curve.

1. lag phase: The early phase of population growth during which no signs of growth occur. 2. exponential growth phase: The period of maximum growth rate in a growth curve. Cell population increases logarithmically. 3. stationary growth phase: Survival mode in which cells either stop growing or grow very slowly. 4. death phase:End of the cell growth due to lack of nutrition, depletion of environment, and accumulation of wastes. Population of cells begins to die.

Discuss characteristics of biofilms that differentiate them from planktonic bacteria. Give some patient examples. Review Figure 6.7.

Biofilms are mixed communities of bacteria and other microbes that are attached to a surface and each other. They form a multilayer conglomerate of cells and intracellular material. The attached cells are stimulated to release chemicals as the cell population grows. Ex: biofilm grown on a gauze bandage

List the essential nutrients of a bacterial cell. Use acronym CHONPS.

Carbon Hydrogen Oxygen Nitrogen Phosphorus Sulfur

Identify important structural and functional differences between RNA and DNA.

DNA contains Thymine to pair with Adenine; RNA contains Uracil to pair with Adenine. The sugar in the backbone of DNA is deoxyribose; the sugar in the backbone of RNA is ribose. DNA has a double-stranded helical form; RNA has a single-stranded helical form

Discuss the primary reason that antiviral drugs are more difficult to design than antibacterial drugs.

antiviral drugs block replication by targeting the functions of host cells and have severe side effects.

Explain methods of moist heat control and identify multiple examples. Table 9.5

disinfection, pasteurization, auto clawing, incineration and hot air oven. examples: glassware, wilds, powders, wines and more

Provide an overview of the relationship among DNA, RNA, and proteins. Relate the new and old versions of the "central dogma" of biology.

not all DNA and RNA are turned into proteins. only 3% are turned into proteins.

Name two types of passive transport and one type of active transport. Table 6.4may help you.

passive transport: 1. simple diffusion 2. facilitated diffusion active transport (needs ATP): 1. carrier mediated

Discuss the size of viruses relative to other microorganisms. Review Figure 5.1

smallest viruses are parvoviruses around 20nm in diameter. largest viruses are mimiviruses around 450 nm in length. some are so long they can't be seen without electron microscopes.

Explain the importance of viral surface proteins, or spikes.

spikes can be found on a naked or an enveloped viruses. allows viruses to dock with the host cells.

Explain in detail the five-step life cycle of animal viruses. Review Table 5.4

step 1: adsorption; a virus that can invade its host cell only through making an exact fit with a specific host molecule. cells that lack compatible receptors are resistant to adsorption and invasion by that virus. step 2: penetration and uncoating; the flexible cell membrane of the host is penetrated by the whole virus or its nucleic acid. endocytosis and direct fusion. step 3: synthesis; DNA viruses enter the host cells nucleus and are replicated and assembled there. RNA viruses are replicated and assembled in the cytoplasm. step 4: assembly; puts new viruses together using manufactured in synthesis process, new capsids and new nucleic acids. step 5: release; the number of viruses released by infected cells is a variable controlled by size of the furs, health of host cell.

Explain the mode of action of chlorhexidine.

targets bacterial membranes, where it stops the membrane's ability to be semipermeable, and proteins, which results in denaturation (breaking of weak bonds); chlorahexadine is in contact solution

Describe the function and structure(s) of viral capsids.

the structure is composed of regular repeating subunits that give rise to their crystalline appearance. acts as external coating and the core contains one or more nucleic acid stains of DNA and RNA.

Define doubling time and how it relates to exponential growth. Figure 6.9 may help you understand.

the time required for a complete fission cycle from parent cell to two daughter cells.

List the possible nucleic acid configurations that viruses may possess. Review Table 5.3

there is wide variety of DNA and RNA also can't be both at same time: DNA: double and single stranded ex. herpes simplex II and parvovirus. RNA: single (+or-) stranded and double stranded ex. influenza and HIV.

Explain what cytopathic effects are and list types. Review Figure 5.7

they are viruses which induce damage to the cell that alters its microscopic appearance. some types are: -gross changes in shape and size -inclusion bodies -syncytia

Identify applications for ethylene oxide sterilization.

used to clean delicate medical instruments that would be damaged by harsher methods

Identify better terms for viruses than "alive" or "dead." Explain both sides of the debate about viruses.

viruses are better described as active or inactive. 1. can't replicate host cells, so they aren't living things and should be called infectious. 2. doesn't exhibit life process of the cells, which are more inert and lifeless molecules.

Analyze the relative importance of viruses in human infection and disease. Scan Table 5.6

viruses are extremely common causes for acute infections such as colds, chicken pox, influenza, and warts. Some viruses have high mortality rates, such as Ebola and AIDS. Others can lead to long term debility such as polio.

Describe each of the steps in the process of transcription. Table 8.3 may help you.

*main goal is to get DNA copied. 1. Initiation- initiated when RNA polymerase recognizes a segment of DNA called a promoter region (this region provides the signal for RNA polymerase to bind to DNA); only one strand of DNA is copied, called the template strand. 2. Elongation- the mRNA is assembled by the addition of nucleotides complimentary to the DNA template in the 5' to 3' direction. 3. Termination- polymerases recognize another code that signals the separation and release of the mRNA, or transcript.

List advantages and disadvantages to phenolic compounds.

- Advantages: effective against cellular toxins - Disadvantages: very toxic; dangerous to use as antiseptics

dentify advantages and disadvantages of cold and desiccation.

- Advantages: slow growth, preservation 70℃ - Disadvantages: microbiostatic, psychrophiles secrete toxins - Advantages: vegetative cells dehydrate, food preservation - Disadvantages: endospores survive, bacteria survive dried secretions

Describe and define three forms of horizontal gene transfer used in bacteria. Table 8.7 may help

- Conjugation- attachment of two related species and the formation of a bridge that can transport DNA - Transformation- the transfer of naked DNA - Transduction- transfer of DNA from one bacterium to another through a bacterial virus

Differentiate among frameshift, nonsense, silent, and missense mutations.

- Frameshift Mutation: the reading frame of mRNA has been changed→ most of the time result in a nonfunctional protein - Nonsense Mutation: changes a codon into an anticodon→ stops production of a protein - Silent Mutation: no effect→ alters a nitrogenous base but not the amino acid - Missense Mutation: any change in the code that leads to placement of a different amino acid

Differentiate between the two types of radiation control methods.

- Ionizing: good for sterilizing materials sensitive to heat and chemicals; gamma rays and X rays - Non-Ionizing: used to sterilize liquids; UV Rays

Identify the microorganisms that are most resistant and least resistant to control measures. Figure 9.2 may help you.

- Most Resistant: prions, bacterial endospores -Medium Resistance: protozoan trophozoites, most gram-negative bacteria - Least Resistant: most gram-positive bacteria, enveloped bacteria

Clearly define the terms. Table 9.1 and Figure 9.1 may help you. a)sterilization b)disinfection c)decontamination d)sanitization e)antisepsis f)degermination

- Sterilization: destroys ALL microorganisms; autoclaves, chemicals - Disinfection: physical process or chemical agent to destroy VEGITATIVE pathogens but not bacterial endospores - Decontamination/ Sanitize: cleansing technique that mechanically removes microorganisms as well as other debris to reduce contamination to safer levels; soaps, pasteurization - Antisepsis/ Degermation: reduces the number of microbes on human skin; forms of decontamination but for living tissues; alcohol, surgical hand soap

Discuss chlorine and iodine and their uses. Table 9.9

- When combined with water, releases hypochlorous acid→ kills bacteria, endospores, fungi, and viruses - Penetrates cells of microorganisms and interferes with their metabolic functions, Various iodine mixtures are used as antiseptics and disinfectants

Define the term mutation. Discuss one positive and one negative example of mutations related to microorganisms.

- a change in the hereditary life of DNA. - Positive Example: organisms can adapt to their biological changes - Negative Example: nonfunctional protein, functions in a different manner; some mutations become resistant to antibiotics

Draw or describe a segment of DNA, labeling all important chemical groups. Use Figure 8.3 for help.

- composed of combinations of nucleotides. most viruses have double stranded DNA with few exceptions. the nucleotides covalently bond to each other in a sugar-phosphate linkage that becomes the backbone of each strand. cytosine-guanine : adenine-thymine

dentify some heavy metal control agents.

- contain either an organic or an inorganic metallic salt; can be used to help treat wounds ex: Mercury and Silver

Distinguish between enveloped and naked viruses.

- is an external covering of a nucleocapsid, usually modified pieces of the host cell membranes. -consist only of nucleocapsid.

Define a bacteriophage. List the steps of the lytic cycle of bacteriophage infections. Explain the lysogenic state. Review Figure 5.9

- it was discovered by Twort and D'Herelle in 1915. most contain double-stranded DNA but some have RNA. viruses that infect bacteria we now turn to the life cycle of another type of virus. 1.absorbtion: a process of adhering one molecule onto the surface of another molecule. 2. penetration: the step in viral multiplication in which virus enters the host cell. 3. uncoating: the process of removal of the viral coat and release of the viral genome by its newly invaded host cell. 4. synthesis: the step in viral multiplication in which viral genetic material and proteins are made through replication and transcription/ translation. 5. assembly: the step in viral multiplication in which capsids and genetic material are packaged into virions. 6. release: the final step in the multiplication cycle of viruses in which the assembled virus particle exits the host cell and moves on to infect another cell. -Alternatively, phages can be less obviously damaging, in a cycle.

Compare the action of microbiocidal and microbiostatic agents, providing an example of each.

- kills microorganisms; antiseptics - inhibits the growth of microorganisms; drugs

What is DNA recombination? Define recombinant.

- one bacterium donates DNA to another bacterium. a type of genetic transfer. - organism that contains genes that originated in another organism.

Define the terms codon and anticodon.

- sequence of three nucleotides that represent a specific amino acid. -on one end of the tRNA is the amino acid and on the other is a set of three nucleotides that are complementary to codon.

Define thermal death time and thermal death point.

- shortest length of time to kill all microbes at a specific temperature - the lowest temperature necessary to kill all microbes in a sample in ten minutes

Identify three methods besides a growth curve to analyze and count bacteria.

1. genetic probing 2. turbidity 3. counting

Differentiate between genotype and phenotype.

- sum of structural genes that code for proteins, genes that code for RNA in protein production and regulatory genes that control gene expression. together they make an organisms genetic makeup. - the expression of genotype traits. certain structures or functions.

Define the terms genome and gene.

- sum total of genetic material of an organism. - fundamental unit of heredity for a trait in an organism.

Identify the effects of isotonic, hypotonic, and hypertonic conditions on a cell. Review Figure 6.3

- the environment is equal in solute concentration to the cell's internal environment. - solute concentration of the external environment is lower than that of cell's internal environment. - the environment has a higher solute concentration than the cytoplasm.

Compare and contrast the process of diffusion and osmosis.

- the phenomenon of molecular movement, which atoms or molecules move in a gradient from an area of higher density or concentration to an area of lower density or concentration. - the diffusion of water through a selectively or differently preamble membrane.

Discuss the disadvantages of aldehyde agents.

- unstable, toxic to people and irritates skin easily.

Explain how filtration and osmotic pressure function as control methods.

- used to prepare liquids that can't withstand heat, blood products, vaccines and IV fluids. -creates hypertonic environment, not a sterilizing techniques.

Name four categories of cellular targets for physical and chemical agents. Review Table 9.3

-Cell wall: damage by digesting it; detergents, alcohol -Cell Membrane: agents bind to the membrane which opens it up allowing chemicals to enter the cell and important ions to exit; detergents - Cellular Synthetic Processes: interrupt protein synthesis; formaldehyde, radiation, ethylene oxide -Proteins: break down; moist heat alcohol, phenolics

Discuss both persistent and transforming infections and give examples of each.

-accumulated damage from a virus infection that kills most cells. it can last few weeks or longer. ex. chicken pox -effects on the cell caused by oncogenic viruses. can cause cancer ex. provirus and HPV.

discuss the difference between moist and dry heat methods.

-lower temperature 60-135℃, shorter times, coagulation/ denatures proteins, microbiostatic, examples -higher temperatures, 160→ 1000s℃, longer times, dehydrates cell→ no water for function, oxidizes (burns to ashes), microbiocidal, examples

Define saprobe and parasite, and provide microbial examples of each.

-metabolizing the organic matter of dead organisms, ex. fungi and bacteria. -utilizing the tissues, fluids of live host, ex. protozoa and animals.

Differentiate between macronutrients and micronutrients.

-required in relatively large quantities and play a principal roles in cell structure and metabolism. -present in much smaller amounts and are involved in enzyme functions and maintenance of the protein structure.

Compare and contrast the synthesis of leading and lagging strands during DNA replications.

-synthesized in the 5' to 3' orientation (phosphate group); "leading" because replication can only progress in this direction -synthesized in the 3' to 5' orientation (sugar group)

List the three types of RNA directly involved in translation. Table 8.4 may help you.

1- mRNA: carries copies of the instructions for assembling amino acids; used in transcription 2- rRNA: in ribosomes; assembles nucleotides to be turned into amino acids to form polypeptide chains; used in translation 3. tRNA: translates from the language of nucleotides to the language of amino acids; used in translation

List and describe the five types of associations microbes can have with their hosts. The concept map on page 154 may help.

1. mutualism: Organisms living in an obligatory but mutually beneficial relationship. 2. commensalism: An unequal relationship in which one species derives benefit without harming the other. 3. parasitism: A relationship between two organisms in which the host is harmed in some way while the colonizer benefits. 4. syngerism: The coordinated or correlated action by two or more drugs or microbes that results in a heightened response or greater activity. 5. antagonism:Relationship in which microorganisms compete for survival in a common environment by taking actions that inhibit or destroy another organism.

Identify three important environmental factors (other than temperature and oxygen) with which organisms must cope

1. pH 2. osmotic pressure 3. radiation

List and define five terms used to express a microbe's optimal growth temperature. Give some examples of locations for each temperature. Review Figure 6.4

1. psychrophile: below 15*C ex. lake, snow, freezer. 2. psychrotroph: above 20*C refrigerator. 3. mesophile: room temp. 20-40*C 4. thermophile: above 45*C volcanic activity or hot tubs. 5. extreme thermophile: 80-120*C.

Summarize three ways in which microorganisms function in the presence of differing oxygen conditions. List and define the five categories that group how different organisms deal with oxygen. Table 6.5

1. those that use oxygen and detoxify it. 2. those that can neither use oxygen nor detoxify it. 3. those that don't use oxygen but can detoxify it. a. aerobes: a microorganism that grows in the presence of air or requires oxygen for growth. b. microaerophiles: a microorganism that requires oxygen to survive, but requires environments containing lower levels of oxygen than are present in the atmosphere. c. facultative anaerobes: an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent. d. anaerobes: an organism that grows without air, or requires oxygen-free conditions to live. e. aerotolerant anaerobes:fermentation to produce ATP. They do not utilize oxygen, but they can protect themselves from reactive oxygen molecules. In contrast, obligate anaerobes can be harmed by reactive oxygen molecules.

Describe three ways in which viruses are cultivated.

1. using live animal inoculation 2. using bird embryos 3. using cell (tissue) culture techniques

Summarize the steps of cell division used by most bacteria. Review Figure 6.8.

1. young cell 2. chromosomes are replicated and new and old chromosomes move to different sides of the cell. 3. protein band forms in center of cell 4. septum formation begins 5. when septum is complete, cells are considered divided. Some species will separate completely, while others remain attached, forming chains and doublets.

List and define four different terms that describe an organism's sources of carbon and energy. Review Table 6.2

1.Photoautotroph: An organism that utilizes light for its energy and carbon dioxide chiefly for its carbon needs. 2.Chemoautotroph: An organism that relies upon inorganic chemicals for its energy and carbon dioxide for its carbon. Also called a chemolithotroph. 3.Photoheterotroph: hey are organisms that use light for energy, but cannot use carbon dioxide as their sole carbon source. 4.Chemoheterotroph:Microorganisms that derive their nutritional needs from organic compounds.

Summarize the steps of bacterial DNA replication. Be sure to identify the enzymes used in the process. Review Table 8.2

1.Strands unwind in the 5' to 3' orientation. Unwinding is regulated by the enzyme Topoisomerase, but the actual unwinding is done by the enzyme helicase. 2. A piece of RNA primer binds to 3' end of the strand. The primer always binds to the point of DNA where replication will begin. The enzyme Primase, generates primers. 3. Polymerase 3 (an enzyme) binds to the strand where the primer is and adds new base pairs to the ones already present. 4. After the strands have been formed, the enzyme exonuclease removes all the primers. The primers are replaced with the appropriate nucleic bases. The enzyme DNA Ligase joins Okazaki fragments to make a unified strand. 5. The end of the parental strand has repeating nucleotides called telomeres; they prevent the strand from bonding with other strands. They are synthesized by the enzyme telomerase. Once finished the DNA resumes its helical shape. 6. In the end, DNA replication produces two DNA molecules, one old strand and one new.

Name the desirable characteristics of chemical control agents.

Rapid action even in low concentration, Solubility in water or alcohol and long-term stability, Broad spectrum microbicidal action, Penetration of inanimate surfaces, Resistance to becoming inactivated by organic matter, Noncorrosive or non-staining properties, Sanitizing and deodorizing properties, Affordability and readily availability

Explain what it means when viruses are described as "filterable."

They found out that fluids from host organisms are passed through porcelain filters are designed to trap bacteria, the filtrate remained infectious. results proved that a cell free fluid could contain agents that could cause infections.

Explain the applications of hydrogen peroxide agents.

Used for cleaning skin and wounds, Can be used to treat infections caused by anaerobic bacteria, Used in low temperature sterilizing cabinets for delicate instruments

Define prion. Describe two diseases caused by prions.

a common feature of spongiform encephalopathies is distinct protein fibrils in the brain tissue. *creutzfeldt-jacob disease *BSE bovine spongiform encephalopathies or mad cow disease.