Microbiology
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Microbiology - Leaderboard
Microbiology - Details
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172 questions
| 🇬🇧 | 🇬🇧 |
| Exchange of nucleotide sequences often occurs between | Homologous sequences |
| Difference between horizontal and vertical gene tranfer | Vertical gene transfer is passing of genes from parent to next generation whereas horizontal is between two different mature bacteria |
| 3 types of horizontal gene transfer | Transformation, transduction, conjugation |
| Define transformation | Bacteria takes up naked DNA from environment |
| Define transduction | Transfer of DNA via replicating virus |
| The virus in transduction must be able to infect what | Donor and reciepient cells |
| Types of transduction | Generalized and specialized |
| What do phages enzymes do upon entering host cell | Degrades host cell DNA |
| What happens after host DNA degradation | New phages are produced to engulf phage DNA |
| What else happens due to this | Host DNA is taken by accident |
| Define conjugation | Transfer of F+ plasmid |
| How does F+ attach to F- cell | Using its sex pilus |
| What is an HFR cell | F+ incorporated in host DNA |
| End result of HFR transfer | Reciepient is still F- |
| Transposons all contain | Palindromic sequences at end |
| Frameshift insertions that occur due to transposons | Transposition |
| Two types of transposons | Jumping and replication transposons |
| Which type of transposon cannot transfer onto a plasmid | Jumping transposon |
| Type of transposon that contains genes not related to transposition | Complex transposon |
| Simplest transposon contains what (2) | One gene, 2inverted repeats |
| Difference between cide and statis/static | Cide is killing whereas statis is just inhibiting growth |
| 2 examples of antisepsis | Iodine and alcohol |
| Due to antisepsis being used on living tissues, what precaution is taken | Its strength is reduced |
| Examples of cides | Fungicides, germicides and virucides |
| Examples of germicides (3) | Ethylene and propylene oxides, aldehydes |
| Removal of microbes by mechanical means | Degermining |
| 2 ways of degerming | Handwashing and alcohol swabbing before injections |
| Four examples of disinfectants | Soaps, alcohols, aldehydes, phenolics |
| What does pasteurization do? | Just prevents more microbes from growing but they are stil present |
| Examples of sanitation | Washing dishes and tableware with scalding water |
| Two examples of sterilization | Preparation of culture and canned food |
| Typically achieved by steam under pressure | Sterilization |
| How do antimicrobial agents destroy microbes(2) | Altering cell wall/membrane and damge to protein/nucleic acid |
| What happens if cell wall is damaged | Cell loses osmoregulation |
| What happens if cell membrane is altered | Controls movement of solutes in and out so cellular contents may leak out |
| What are the four ideals for a microbial antiagent | Inexpensive, fast-acting, stable during storage, harmless top the object it is protecting |
| What is the most susceptible microbe | Enveloped viruses |
| Which is more susceptible; gram positive or negative | Gram positive |
| What is the second and third most resistant microbe | Bacterial endospores and mycobacteria |
| Why is mycobacteria very resistant | Does not have cell wall to be targeted |
| Classification of germicide where all pathogens including endospores are killed | High-level germicide |
| What do intermediate-level germicides do | Kill fungal spores, viruses, cysts and pathogenic bacteria |
| What mechanism is used to prevent microbes from leaving a room | Negative pressure |
| What is the lowest temperature needed to kill all cells in broth | Thermal death point |
| Time needed to sterilize volume of liquid at a set tremp | Thermal death time |
| 4 moist heat methods for controlling microbes | Boiling, autoclaving, pasteurization, ultrahigh-temp sterilization |
| Aurtoclaving uses what (2) | Pressure and steam |
| In sterile indicators, what does a yellow medium mean | Autoclaved objects are not sterile |
| Ultra sterilized liquids can be store where | Room temperature |
| How is ultra-temp sterilization done | Heated at 140C for 3 secs then rapid cooling |
| Egs of a dry heat method | Incinerator |
| What does dry heat do(2) | Denatures protein and oxidizes metabolic and structural chemicals |
| How is dry heat requirements different from moist heat(2) | Higher temp and longer time period |
| What does refidgeration do to microbes | Halts its growth not kill it |
| What type of freezing is more effective | Slow freezing |
| Another name for drying | Desiccation |
| Another name for freeze-drying | Lyophilization |
| Lyophilization prevents formation | Damaging ice crystals |
| Lyophilization is typically used for | Long-term preservation of microbial cultures |
| Which method uses size | Filtration |
| How does osmotic pressure prevent microbes | High salt/ sugar concentration inhibits growth |
| Two types of radiation | Electromagnetic and particulate radiation |
| Describe particulate radiation | High-speed subatomic particles freed from their atoms |
| Describe electromagnetic radiation | Energy without mass travelling in waves at the speed of light |
| Ionizing radiation involves what three things | X-rays, gamma rays, electron beams |
| What is the problem with using electron beams radiation to kill microbes | Effective but does not penetrate well |
| What is the problem with using gamma rays radiation to kill microbes | Penetrate well but take hours to kill |
| What is the problem with using x-rays radiation to kill microbes | Requires long time to kill |
| What does ionizing radiation do(3) | Disrupts h-bonds, oxidize double bonds, create hydroxyl radicles |
| Nonionizing is used for (3) | Disinfecting air, transparent fluid, surfaces of objects |
| What does the uv light cause | Pyrimidine dimers |
| What limits phenol use | Very reactive so can be used on a few things |
| Phenolics is most effective in the presence of? | Organic matter |
| 2 examples of phenolics | Orthocresol and triclosan |
| Why might one not want to be near phenol | Very bad odor |
| What does phenolics affect in bacteria | Denature their proteins and cell membranes |