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Microbiology
Unit 2 Exam
| Term | Definition |
|---|---|
| Each DNA nucleotide has what? | Deoxyribose, Phosphorus, Nucleoside base (A,G,C,T) |
| What are the reactions of DNA? | Replication, and Gene expression |
| 1 dsDNA yields how many dsDNA? | 2 |
| What holds the DNA strands together? | Hydrogen bonds |
| What is semi-conservative replication? | A new strand of dsDNA is made of one strand of old DNA plus one strand of new DNA |
| What is the replication fork? | The area where the strands of DNA are unzipped |
| Origin in DNA | Where the replication starts |
| Terminus IN DNA | Where the replication ends |
| T/F Is Prokaryotes DNA a circular structure? | T |
| What happens at the replication apparatus? | It separates the dsDNA, synthesizes new ssDNA, and it moves the replication fork along the strand |
| DNA helicase | separates and moves the strands apart |
| DNA polymerase III | synthesizes 2 new ssDNA |
| Single-strand binding protein (ssBP) | keeps the strands separated during the process |
| Primase | makes an RNA primer |
| DNA polymerase I | adds DNA to the RNA primer moving away from the fork |
| DNA ligase | binds the pieces together to make a single strand |
| What are the bases for DNA? | A, T, G, and C |
| What are the bases for RNA? | A, G, U, and C |
| What is transcription? | DNA on a gene is transcribed into RNA |
| What the 3 types of RNA? | mRNA, tRNA, and rRNA |
| What are the 4 differences between RNA replication and DNA replication? | 1. Only 1 strand of RNA is transcribed at a time (no leading or lagging strand), 2. results in a ssRNA as the final product (ss = ss), 3. the strands are shorter, and 4. only one enzyme - RNA polymerase - is used for the process. |
| Promoter in RNA | Process starts |
| Terminator in RNA | Process ends |
| What is translation? | The process of using the transcribed info (DNA --> ssRNA) to make a protein. |
| What does mRNA do? | Carries the info of the order of the amino acids for the protein. |
| What does tRNA do? | Translates info between the mRNA and the protein. |
| What does rRNA do? | Is a part of the ribosome where the actual ordering process occurs (builds the protein) |
| What is a codon? | Information is read in a 3 base pattern. |
| What is an anti-codon? | Information that is translated by tRNA. |
| How do mutations occur? | When there is a chemical change in DNA. |
| What is a genome? | DNA of a cell. |
| What is a plasmid? | Non-essential genes. |
| What is PCR? | Polymerase Chain Reaction |
| How is PCR used? | PCR is used to dx diseases. It checks out a single gene, then makes millions of copies of it - enough to test. |
| What are the characteristics of a virus? | Accelular, not pro or eukaryotes, they have genetic material in the form of DNA and RNA that is inside a protein coating. They replicate by taking over a host cell, and they can't replicate on their own. |
| How are viruses classified? | Host range, size, structure, and life cycle. |
| How are viruses named? | The have 3 levels: family, genus, and species. |
| Taxonomy of viruses | Family names ALL end in viridae, Genus names end in virus, and Species names are common English words. |
| What is the lytic cycle? | Its a pathway by which the host cell lyses, virions (viruses) are released, and virulent form. |
| What is the lysogenic cycle? | Its a pathway by which the host cells do not lyse, virus is held in the cell. (virus is waiting for the right conditions be activated and lyse the cell) |
| What is a prion? | Proteinaceous infectious particles that contain no nucleic acid (acellular). |
| What does the distribution of a drug depend on? | The cell membrane, and the proteins that bind to the drug. |
| What prevents free passage of drugs in and out of the cell? | Cell membranes |
| Protein binding drugs | Proteins in the blood that bind to the drug so it cannot cross the membrane. |
| What is natural resistance to a drug? | The microbe may lack a receptor for the drug or be naturally resistant based on its cell wall structure. |
| What is acquired resistance to a drug? | The microbe may have mutations or gene exchange may have occurred. |
| How does acquired resistance occur with mutations? | The receptor on the microbe changes, there is a change in the cell membrane that excludes the drug, or the microbe begins to produce an enzyme that inactivates or destroys the drug (most common way). |
| How does acquired resistance occur with genetics? | The microbe gets a plasmid from another resistant microbe |
| What is narrow spectrum? | Drugs that are only effective on single to small numbers of microbe groups. |
| What is a broad spectrum? | Drugs that are effective against more than 1 group of microbes. |
| What are the 5 drug targets? | Cell wall, cell membrane, protein synthesis, folic acid synthesis, and nucleic acid synthesis. |
| What are 3 methods drugs work on bacteria? | Lyse, mess with metabolism/synthesis, or mess with replication. |
| What is bactericidal? | Microbial death. |
| What is bacteriostatic? | Slowing the growth of microbes. |
| How do antimycobacterial drugs work? | Mycobacterium live intracellularly, so the drug must enter the human cell to treat infection. |
| What is a reservoir? | A place for a disease to occur. Must be one of the following: human, animal, or environment. |
| What are the 7 steps required for transmission of a microbe? | 1. Have a reservoir, 2. Leave the reservoir and enter a host, 3. Adhere to a surface of the host, 4. Invade the body of the host, 5. Evade host defense mechanisms, 6. Multiply in the host, 7. Leave the host and return to the reservoir or invade another ho |
| What are the different types of toxins? | Endotoxin and Exotoxin |
| What are endotoxins? | Act on G- bacteria, means part of or into the cell. ALL produce as part of lipids A of the LPS part of their outer membrane . Lipid A activates C and stimulates macrophages to release cytokines which signal the body to activate immune defenses. |
| What are exotoxins? | Act on G+ and G- bacteria, released outside the cell and are secreted proteins that kill the host cell at low concentrations due to their membrane disrupting capabilities. |
| Phenols | Kill by denaturing vital proteins. |
| Alcohols | Kill by disrupting the lipids in the cell membranes and denaturing the proteins. |
| Halogens and Hydrogen Peroxide (H2O2) | Halogens = iodine, chlorine. Both are oxidizing agents - they inactivate the proteins present. |
| Heavy metals | Salts of metals kill microbes. |
| Surfactants | Work to break apart oils into small bits = emulsion. Work like soaps and detergents; oils have microbes in and on them, so if you get rid of the oil you get rid of the microbe. |
| Alkylating Agents | Ethylene oxide (EO), formaldehyde, glutaraldehyde. Have an alkyl group attached to a protein which inactivates the enzymes and kills the cells. |
Created by:
RTadesse
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