Exam 2 Study Guide
Exam 2 Study Guide MCB2000
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This 9 page Study Guide was uploaded by Isabella Morles on Sunday October 9, 2016. The Study Guide belongs to MCB2000 at University of Florida taught by Dr. Asghari in Spring 2016. Since its upload, it has received 46 views. For similar materials see Microbiology in Microbiology at University of Florida.
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Date Created: 10/09/16
MCB 2000 Study guide for EXAM TWO 1.State the difference between and give examples of vertical and horizontal gene transfer? Vertical gene transfer – genes go from parent to daughter cells (disease from parent to offspring via ovum, sperm, placenta, or milk) Horizontal gene transfer one bacteria to another (disease – spread through population from one infected individual to another) 2.Name different RNA molecules. What is the role of each molecule? Which ones contains Codon, anticodon mRNA (codon) codon for protein, makes protein and is used as a template, makes protein, tRNA (anticodon) (transfer RNA) has anticodon that matches mRNA. Bind to amino acids and bring them to ribosomes, rRNA (codon) (RNA and Protein – make up ribosome) reads mRNA used to make proteins, carries codon for amino acid 3.Briefly describe replication, transcription, and translation. What is used as template for each process? Replication doubling DNA – template is old parent cell (chromosome) Transcription DNA into RNA (initiation, elongation, termination) Template is DNA Translation Protein Synthesis, happens in ribosomes, 4.What are the products of: Replication, Transcription, Translation and Reverse Transcription? What are the differences between DNA polymerase an RNA polymerase? What is the significance of reverse transcriptase? What is the source of reverse transcriptase? What does it do? Products: Replication: new DNA strand Transcription: RNA Translation protein molecule Reverse Transcription RNA to DNA DNA polymerase the process of synthesizing a new daughter strand of DNA using parental strand as template is carried about by this enzyme (DNA polymerase III). It cannot begin to synthesize a chain of nucleotides but can only continue to add nucleotides to an already existing chain. Can only add in one direction (5’3”). Enzyme that elongates the molecule can detect incorrect bases and excise them and replace them. DNA Polymerase I removes RNA primers used to initiate DNA synthesis and replaces them with DNA. Can proofread molecule and repair damaged DNA. Reverse transcriptase is an enzyme possessed by retroviruses that carry out the reversion of RNA to DNA (form of reverse transcription) It replicates the Aids virus and other retroviruses. RNA Polymerase opens DNA, zips and finds gene to make RNA. Reads the start of the gene sequence and synthesizes RNA 5.Define/Explain/describe: Complementary strands, Antiparallel, Semiconservative replication, Double helix Double helix DNA shape Antiparallel the strands for the DNA are parallel to each other but the orientation of deoxyribose and phosphate run in opposite directions. One helix runs from 5’ to 3’ and the other 3’ to 5’ Semiconservative replication the preservation of the parent molecule that is used as a template (daughter strand paired with parent) Complementary DNA DNA created by using reverse transcriptase to synthesize DNA from RNA templates 6.List the enzymes and their functions involved in DNA replication Helicase unzipping DNA Primase synthesizing RNA primer DNA Polymerase removing primer, adding basses to new DNA chain (CHECK NOTES), enzyme responsible for the replication of DNA Ligase final binding of nicks in DNA during synthesis and repair Topoisomerases supercoiling and untangling 7.What is the genetic material for viruses, DNA or RNA, single stranded or double stranded? Either double or single stranded DNA / double or single stranded RNA (4 options) 8.Where in eukaryotes and prokaryotes one can find DNA? Eukaryotes chromosomes are found in the nucleus Prokaryotes (Bacteria) nucleoid 9.What are ribosomes made of? Prokaryotes and eukaryotes have different ribosomes? What is the significance of this difference? rNA make up ribosomes. 10.What is meant by recombinant DNA? Restriction enzymes cut DNA at different points and tie with ligase. It has multiple sources. 11.What is the significance of RFLP? Technique used by law enforcement and forensics to get DNA from a small sample (nail, cup) 12.Name several medical, Industrial, and agricultural applications of recombinant DNA. Genome mapping: locating genes and nucleotide sequencing Pharmaceutical and Therapeutic: protein synthesis, vaccines, genetic screening, DNA fingerprinting (RFLP), gene therapy, xenotransplants Other: herbicide resistance, salt tolerance, freeze resistance, pest resistance 13.Name the tools used to make a recombinant DNA. Example; how you cut DNA, how you introduce the DNA to the host cell, how to track the DNA. What is meant by gene library? Protoplast fusion? PCR (Polymerase Chain Reaction) takes DNA and opens it, synthesis, copies and DNA is double. Amplifies DNA Tools: Reverse transcriptase: manipulate DNA and RNA into DNA Synthetic nucleic acids Restriction enzymes cut DNA at specific point Vectors plasmid carry into host Creation of gene libraries collection of bacteria that each carry parts of DNA from host Protoplast fusion – fuse together and become one cell 14.Define spontaneous mutation. What causes spontaneous mutation? Changes that happen naturally (DNA Polymerase). Can be fixed. 15.Define base analogs and explain how they may induce mutation Base analogs resembles bases (nucleotides) act like C but do not pair with G, fits but no interaction (no function), no DNA synthesis Induced mutations cannot be fixed so if the analogs resemble the bases there is no interaction. 16.Define frame shift mutation, induced mutation Frameshift add or take out a base half way through. (shift pairs) Induced mutations cannot be fixed. Causes by chemicals 17.What do alkylating agents and acridine derivatives have in common? Alkylating agents damage the base pair, add groups to incorrect pair Acridine – inserts into DNA ladder Both are part of point mutations – single base changes 18.Describe general features of Eubacteria, Protozoa, Fungi, Viruses, and Archaea 19.List the differences between bacteria and viruses 20.What is meant by obligate intracellular pathogens? Which groups of infectious agents are included? Acellular, need electron microscopy, with host specificity. 21.Name different components of a virus. Name the two that every virus must have Every virus must have nucleic acids and a capsid. It can also have spikes for attachment and envelopes. 22.Distinguish between transforming, persistent, latent, lysogenic, and lytic viral infection Transforming virus affects cell division of host (mutation, cancer) mutate host DNA (don’t kill host) (malignant cells) Persistent keep producing viruses at low level – host survives but keeps producing viruses (chronic) Latent no virus produced, no host dies. Virus coexists with host for long time (not good, can cause problems) Lysogenic Lytic viral 23.What is tissue culture/cell culture/monolayer? What is their use? Why you always need host to grow virus 24.What is the order of virus life cycle? Describe ONESTEP growth cycle? How one grow viruses in lab? 25.What is antigenic shift, and how viruses achieve that 26.Name different shapes of viruses. Which one is unique to viruses? 27.List animal defenses against viral infection. Fever, Interferon, antibodies, and some drugs: ribovirin (HBV and HCV), Tamiflu (influenza A and B), Amantadine (Influenza A), Acyclovir (HSV) 28.What is the role of viruses in cancer? Name the cancers caused by viruses. 20% of human cancer is caused by viruses, either the virus carries the gene or it produces proteins that induce a loss of growth regulation. Oncoviruses mammalian viruses capable of imitating tumors Examples: papillomavirus (genital warts associated with cervical cancer), herpesviruses (lymphoma), hepatitis B (liver cancer) 29.What is plaque assay and what is used for? What is CPE? Give an example Plaque assay dilutions of virus used to infect cultured cell. Area on plate that virus kills host. Results in cell killing. CPE is Cytopathic effects they are virus induced damage to the cell that alters its microscopic appearance, o Example: fusion of multiple host cells – syncytia – respiratory syncytial virus o Human epithelial cells infected by herpes simplex virus demonstrate giant cells with multiple nuclei 30.Define lysogeny and explain its importance in causing diseases by bacteria. Lysogeny is a condition in which the host chromosome carries bacteriophage DNA. Many bacteria that infect humans are lysogenized by phages. Sometimes the phage can produce toxins or enzymes thag cause pathology. 31.Define exotoxins, endotoxins, neurotoxin, and enterotoxin. What each is made of? Who makes them? Exotoxin a toxin (usually protein) that is secreted and acts upon a specific cellular target. Endotoxin (LPS) 32.List the consequences of release of endotoxin 33.List the five stages of disease. Define sign, symptom, and syndrome Sign any objective evidence of disease as noted by an observer. More precise than symptoms. Symptom subjective evidence of disease as sensed by the patient Syndrome the collection of signs and symptoms that, taken together, paint a portrait of the disease. 34.Name reservoirs of infection, what are the reservoirs for influenza and rabies Rabies mammals Influenza Chickens, birds, swine Reservoirs Living: animals, humans, anthropoids Nonliving: air, water, soil, the built environment 35.Define direct/indirect contact, droplet transmission, vehicle transmission, vector transmission, Direct involves physical contact between infected person and that of the infective Droplet in which fine droplets are sprayed directly upon a person during sneezing and coughing Indirect infected individuals contaminate objects, food, or air through activities Fomite inanimate object that harbors and transmits pathogens (doorknobs, telephone) Vehicle a natural, nonliving material that can transmit infectious agents Vector Mechanical insect carries microbes to host on its body parts Biological insect injects microbes into host: part of microbe life cycle completed in insect 36. Define Virulence. Name several virulence factors and indicate how they may harm their host tissues In infection, the relative capacity of a pathogen to invade and harm host cells. 37. Identify different port of entry for infectious agents. Give examples 38.Koch's postulates cannot be proven for some organisms. Name two exceptions to Koch’s postulates. Some infectious agents cannot be readily isolated or grown in a lab. Viral diseases are hard because viruses usually have a very narrow host range Usually not possible to determine causation in polymicrobial diseases (like soft tissue abscesses and periodontitis) 39.Define nosocomial infection, its causative agents? An infection not present upon admission to a hospital but incurred while being treated there. Causative agents surgical procedures, fomites, medical equipment, other patients, medical personal, visitors, air and water Most common: urinary tract, respiratory tract and surgical incisions 40.Name factors in the triangle of infection. What is the significance of each factor? Host age, health, genetics, immune system Environment public health Microbes growth rate, number of microbes in infection, route of entry 41.Define symbiosis, name and describe different forms of symbiosis Symbiosis close associating between 2 or more organisms • Parasitism one benefits and the other is harmed • Mutualism both benefit (bacteria in human colon) • Antagonism • Commensalism one benefits and the other is neither hurt nor benefits 42.Define different forms of disease outbreaks, epidemic, pandemic, etc. Endemic: a native disease that prevails continuously in a geographic region. Cases are concentrated in one area at a relatively stable rate. Pandemic: a disease afflicting an increased proportion of the population over a wide geographic area (often worldwide) Epidemic: a sudden and simultaneous outbreak or increase in the number of cases of disease in a community. Often appear in geographical clusters. Sporadic description of a disease that exhibits new cases at irregular intervals in unpredictable geographic locations. 43.What is the significance of an opportunistic pathogen? Name an opportunistic microbe In infection, ordinarily nonpathogenic or weakly pathogenic microbes that cause disease primarily in an immunologically compromised host. It causes diseases when the host’s defenses are down. Example: Pseudomonas species and Candida Albicans 44.What are the characteristics of skin that make it resist infection? Low ph., low temperature, salt and epidermis 45.Define fomite/carrier/chronic carrier/reservoir of infection Reservoir of Infection in disease communication, the natural host or habitat of a pathogen Carriers a person who harbors infections and inconspicuously spreads them to others. Chronic carrier individuals who shelter the infectious agent for a long period after recovery because of the latency of the infectious agent Fomite inanimate object that harbors and transmits pathogens (doorknobs, telephone) 46.Define three approaches in epidemiological study The epidemiologist collects information on the causative agent, pathology, sources, and modes of transmission and tracks the numbers and distribution of cases of disease in the community. Descriptive situation, collect data Analytical tabulate results Experimental Koch’s postulates 47.Give three examples of immunecompromised individuals Underlying disease: cancer, liver malfunction, diabetes Old age and extreme youth Genetic defects in immunity Surgery and organ transplants Chemotherapy, immunosuppressive drugs Physical and mental stress Pregnancy and other infections 48.List the factors involved in the decrease of mortality rate over the last 100 years. Vaccines, water treatment (cholera, typhoid fever, diarrheal disease), antibiotics (staph, pneumonia, G) 49.Which of the three domains of microbes are prokaryotes and which ones are eukaryotes? 50.What is meant by notifiable diseases? Give three examples. Reportable – those diseases that must be reported to health authorities by law Examples: anthrax, cancer, cholera, dengue fever, gonorrhea, Hep A,B,C, HIV, Influenza, Lead poisoning, malaria, measles, mumps, meningococcal, yellow fever, varicella, typhoid fever, tetanus, syphilis, small pox, rubella, rabies, plague 51.Important terms relevant to exam TWO: Define/Describe/Explain the following terms: Chromosome discrete cellular structure composed of DNA Gene a site on a chromosome that provides info for a certain cell function. A specific segment of DNA that contains the necessary code to make a protein or RNA molecule Genome: is the sum total of genetic material of an organism (cellsDNA, virusesDNA or RNA) Plasmid they are excellent vectors because they are small, well characterized, easy to manipulate and can be transferred into appropriate cells hosts through transformation. (MORRE) Ribosome Codon every 3 base pairs are a codon (UAC GCA) Anticodon Genetic code Ligase final binding of nicks in DNA during synthesis and repair Helicase unzipping DNA, Reverse transcription retroviruses turn RNA genomes into DNA Exonuclease exonuclease activity (adding nucleotides/removing nucleotides) Mutagens Carcinogens Ames Test looks for damage to bacteria DNA by looking for metabolic activity. Recombinant DNA, gel electrophoresis a lab technique for separating DNA fragments according to length by employing electricity to force the DNA through a gellike matrix. Smaller fragments move quicker than longer fragments., PCR a technique that amplifies segments of DNA for testing. Using denaturation, primers, and heatresistant DNA polymerase, the number can be increased several million fold. Increases DNA in sample without need to make cultures. Restriction enzymes (endonucleases) an enzyme present naturally in cells that cleaves specific locations on DNA. Also used to splice genes in genetic engineering Vectors an animal that transmits infectious agents from one host to another, usually a biting or piercing arthropod like a tick, fly or mosquito. Also a genetic element such as a plasmid or bacteriophage used to introduce genetic material into a cloning host during recombinant DNA experiments. Gene library (genomic) collections of DNA fragments representing the entire genome of an organism inserted into plasmids and stored in vectors such as bacteria or yeasts. Etiology (etiologic) the microbial cause of disease the pathogen Koch’s postulates a procedure to establish the specific cause of disease. In all cases of infection: the agent must be found, inoculations of a pure culture must reproduce the same disease in animals, the agent must again be present in the experimental animal and a pure culture must again be obtained. Zoonosis an infectious disease indigenous to animals that humans can acquire through direct or indirect contact with infected animals Viruses (Obligate intracellular parasites that cannot multiple without a specific host cell, they are not cells, they are very small, impact life, do not fulfil characteristics of life, not alive or dead but inactive and active) Capsid helps with attachment (protein) Spike helps with attachment to specific host Envelope outer, flexible layer that some viruses have Icosahedra Plaques assay Uncoating Prion Virion Viroid Endotoxins Exotoxins a toxin (usually protein) that is secreted and acts upon a specific cellular target Enterotoxins Neurotoxins Contamination Infection Disease any deviation from health, as when the effects of microbial infection damage or disrupt tissues and organs Infectious diseases the state of damage or toxicity in the body caused by an infectious agent. Communicable diseases capable of being transmitted from one individual to another contagious diseases communicable, transmissible by direct contact with infected people and their fresh secretions or excretions Reservoir of Infection in disease communication, the natural host or habitat of a pathogen Animate Inanimate Carriers a person who harbors infections and inconspicuously spreads them to others. Chronic Carrier individuals who shelter the infectious agent for a long period after recovery because of the latency of the infectious agent Modes of Transmission Direct vs indirect transmission vector transmission vehicle transmission Arthropodborne diseases diseases transmitted by bite of insect (like malaria) Triangle of Infection; host, microbe, environment: Host age, health, genetics, immune system Environment public health Microbes growth rate, number of microbes in infection, route of entry Endemic: a native disease that prevails continuously in a geographic region. Cases are concentrated in one area at a relatively stable rate. Pandemic: a disease afflicting an increased proportion of the population over a wide geographic area (often worldwide) Epidemic: a sudden and simultaneous outbreak or increase in the number of cases of disease in a community. Often appear in geographical clusters. Nosocomial infections also called healthcare associated, an infection not present upon admission to hospital but incurred while being treated there. Symbiosis close associating between 2 or more organisms Parasitism one benefits and the other is harmed Mutualism both benefit (bacteria in human colon) Antagonism Commensalism one benefits and the other is neither hurt nor benefits LD 50/ID50 Routes of Entryroute of entry for an infectious agent; typically, a cutaneous or membranous route. Exit for microbes route through which a pathogen departs from the host organism; skin, mucosal route (GI tract, UG tract, Respiratory tract, Parenteral route Normal Microbiota (normal flora) Virulence Factors a microbe’s structures or capabilities that allow it to establish itself in a host and cause damage. Virulence in infection, the relative capacity of a pathogen to invade and harm host cells. Capsule, Adhesion, pili, fimbriae WHO / CDC Notifiable diseases– those diseases that must be reported to health authorities by law MMWR, Mortality rate the number of persons who have died as a result of a particular cause or due to all causes, expressed as a numerator, with the denominator being some unit of population (as in x/100,000). Morbidity rate the number of persons afflicted with an illness under question or with illness in general, expressed as a numerator, with the denominator being some unit of population (as in x/100,000) DNA strand heat breaks it apart and cold brings it together There are four distinct phases of infection and disease: the incubation period (initial contact with infectious agent and appearance of symptoms), the prodrome (short period of mild symptoms occurring at the end of period of incubation, onset of disease), the period of invasion (infection multiplies at high levels, exhibits its greatest toxicity, and becomes well establish in the target tissues), and the convalescent period (recovery). Multiplication Cycles in Animal viruses: adsorption, penetration and uncoating, synthesis, assembly and release Adsorption virus must have an exact fit with a specific host module (so a canine infection cannot hurt humans) Penetration and uncoating whole virus or nucleic acids enters host, if whole virus comes in it is enclosed by enzymes and nucleic acid comes out Synthesis (replication) Most DNA viruses enter host cell’s nucleus and replicate there. RNA viruses usually replicate in the cytoplasm. Assembly puts together new viruses Release viral release from host. The number of viruses released depend on virus size, and health of host cell. Cancer:
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