Viruses
Terms : Hide Images
| 6320779255 | Virus | An infectious particle incapable of replicating outside of a cell, consisting of an RNA or DNA genome surrounded by a protein coat (capsid) and, for some viruses, a membranous envelope. |  | 0 |
| 6320779256 | Capsid | The protein shell that encloses a viral genome. It may be rod-shaped (helical), polyhedral(icosahedral), or more complex in shape. | 1 | |
| 6321065189 | capsomeres | protein subunits that make up capsids | 2 | |
| 6320779257 | Viral Envelopes | A membrane, derived from membranes of the host cell, that cloaks the capsid, which in turn encloses a viral genome; contain host cell phospholipids and membrane proteins; contain viral proteins and glycoproteins | 3 | |
| 6320779258 | Bacteriophage (Phage) | -viruses that infect bacteria -capsids w/ elongated icosahedral heads w/ DNA -protein tail piece w/ fibers by which phages attach to bacterium attached to head |  | 4 |
| 6320779259 | Host Range | limited number of species whose cells can be infected by a particular virus | 5 | |
| 6320779260 | Viral Reproduction Cycle | 1. virus binds to host cell and enters uncoated, releasing viral DNA and capsid proteins 2. viral genome encodes proteins to have host reprogram cell to copy viral nucleic acid and replicate viral genome 3. meanwhile, host enzymes transcribe viral genome into viral mRNA, which host ribosomes use to make more capsid proteins 4. viral genomes and capsid proteins self-assemble into new virus particles, which exit cell to infect other cells and spread viral infection |  | 6 |
| 6322242656 | Lytic cycle | A type of phage replicative cycle resulting in the release of new phages by lysis (and death) of the host cell. | 7 | |
| 6320779261 | Lytic Cycle process | -phage reproductive cycle that culminates in death of host cell 1. Attachment: page uses tail fibers to bind to specific receptor sites on surface bacteria 2. Entry of phage DNA and degradation of host DNA: sheath of tail contracts, injecting the phage DNA into cell and leaving empty capsid outside -> cells DNA hydrolyzed 3. Synthesis of viral genomes and proteins: phage DNA directs production of phage proteins and copies of phage genome w/ host enzymes 4. Assembly: 3 separate sets of proteins self-assemble to form phage heads, tails, and tail fibers; genome packaged in capsid as head forms 5. Release: phage directs production of enzyme that damages bacterial cell wall -> fluid enters -> cell swells and bursts, releasing 100-200 phage particles |  | 8 |
| 6320779262 | Virulent Phage | a phage that replicates only by a lytic cycle | 9 | |
| 6320784336 | Restriction Enzymes | An endonuclease (type of enzyme) that recognizes and cuts DNA molecules foreign to a bacterium (such as phage genomes). The enzyme cuts at specific nucleotide sequences (restriction sites). | 10 | |
| 6322770527 | Lysogenic cycle | Allows replication of the phage genome without destroying the host | 11 | |
| 6320779263 | Lysogenic Cycle process | phage reproductive cycle w/ replication of phage genome w/o destroying host 1. phage DNA incorporated on site of bacterial chromosome -> prophage 2. bacterium reproduces normally, copying prophage and transmitting it to daughter cells 3. many cell divisions -> large population of infected bacteria |  | 12 |
| 6320779264 | Temperate Phage | phage capable of using both modes of reproduction in bacteria through replication via the lytic or lysogenic cycle. | 13 | |
| 6320779265 | Prophage | phage genome that has been inserted into a specific site on a bacterial chromosome. |  | 14 |
| 6320779266 | Reproductive Cycle of Lipid Enveloped RNA Virus | 1. glycoproteins on viral envelope bind to specific receptor molecules on host cell, promoting viral entry into cell 2. capsid and viral genome enter cell-digestion of capsid by cellular enzymes releases viral genome 3. viral genome functions as template for synthesis of complementary RNA strands by viral envelope 4. new copies of viral genome RNA made using complementary RNA strands as templates 5. complementary RNA strands also function as mRNA, translated into capsid proteins (in cytosol) and glycoproteins for viral envelope (ER, Golgi) 6. vesicles transport envelope glycoproteins to plasma membrane 7. capsid assembles around each viral genome molecule 8. each new virus buds from cell, envelope studded w/ viral glycoproteins embedded in membrane derived from host cell |  | 15 |
| 6320779267 | Retrovirus (Class VI) | An RNA virus that replicates by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome; an important class of cancer-causing viruses. | 16 | |
| 6320779268 | Reverse Transcriptase | An enzyme encoded by certain viruses (retroviruses) that uses RNA as a template for DNA synthesis. | 17 | |
| 6320779269 | HIV | The infectious agent that causes AIDS. HIV is a retrovirus. | 18 | |
| 6320779270 | AIDS | The symptoms and signs present during the late stages of HIV infection, defined by a specified reduction in the number of T cells and the appearance of characteristic secondary infections. | 19 | |
| 6320779271 | HIV Reproductive Cycle | 1. envelope glycoproteins enable virus to bind to specific receptors on certain white blood cells 2. virus fuses w/ cell's plasma membrane-capsid proteins removed, releasing viral proteins and RNA 3. reverse transcriptase catalyzes synthesis of DNA strand complementary to viral RNA 4. reverse transcriptase catalyzes synthesis of second DNA strand complementary to first 5. double stranded DNA incorporated as provirus -> permanent resident of cell 6. proviral genes transcribed into RNA molecules-serves as genomes for next viral generation and as mRNAs for translation into viral protein 7. viral proteins include capsid proteins, reverse transcriptase, and envelope glycoproteins 8. vesicles transport glycoproteins to cell's plasma membrane 9. capsids assemble around viral genomes and reverse transcriptase molecules 10. new viruses bud off host cells |  | 20 |
| 6336305874 | Provirus | A viral genome that is permanently inserted into a host genome | 21 | |
| 6320779272 | Vaccine | harmless variant or derivative of a pathogen that stimulates a host's immune system to mount defenses against harmful purposes | 22 | |
| 6320779273 | Emerging Viruses | viruses that are new to medical scientists/suddenly appear b/c: 1. mutation of existing viruses -> new strains of disease -> epidemics 2. dissemination of viral disease from small, isolated human population-can be due to technological and social factors (radiation, travel, blood transfusion, sexual promiscuity, drugs, etc...) 3. spread of existing virus from other animals | 23 | |
| 6320779274 | Epidemic | huge outbreak of disease | 24 | |
| 6320779275 | Pandemic | global epidemic | 25 | |
| 6356927823 | Horizontal transmission | viral disease in plants spread from an external source through the plant's epidermis (= damgage via wind, herbivores, or injury) | 26 | |
| 6356939442 | Vertical transmission | viral disease in plants spread by inheritance from a parent, can occur asexually and sexually | 27 | |
| 6320779276 | Viroid | a plant pathogen consisting of a molecule of naked, circular RNA a few hundred nucleotides long; replicates in host plant cells using host enzymes instead of encoding proteins cause errors in regulatory system that control plant growth -> stunted growth, abnormal development | 28 | |
| 6320779277 | Prion | an infectious agent that is a misfolded version of a normal cellular protein appears to increase in number by converting correctly folded versions of the protein to more prions, causes many degenerative brain diseases of many animals, mostly transmitted w/ food-incubation 10+ years, virtually indestructible | 29 |
