Ch. 24 Biology Viruses

Front 1

Virus

Back 1

nonliving particle made of nucleic acid and a protein coat or lipid-protein (lipoprotein) coat

Front 2

List some characteristics of viruses

Back 2

1. do not have cytoplasm, or organelles
2. cannot perform cellular functions of metabolism, or homeostasis
3. do contain genetic material, a genome, either DNA or RNA
4. can not reproduce outside a host cell
5. some of the smallest particles able to cause disease

Front 3

capsid

Back 3

protein coat, only layer surrounding some viruses

Front 4

envelope

Back 4

bilipid membrane surrounding the capsid of some viruses (influenza, varicola-chicken pox virus, HIV, poxviruses)

Front 5

name the shape of some viruses

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1. helical (TMV- tobacco mosaic virus, rabies, measles)
2. icosahedron (adenovirus- common cold, herpes simplex, chicken pox, and small pox)
3. spherical (influenza, retroviruses- HIV)

Front 6

Name the info. used to classify viruses

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1. whether they have RNA or DNA, and whether their genome is single stranded or double stranded and linear or circular
2. shape of their capsid, and on the +/- envelope

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obligate intracellular parasite

Back 7

ex: viruses, they can not replicate unless they are inside a host cell so their genome can take over the metabolic machinery of the cell and make new viruses

Front 8

spread of viruses

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air, water, food, body fluids; can infect prokaryotic or eukaryotic cells

Front 9

provirus

Back 9

viral DNA inserted into a host cell's chromosome

Front 10

retrovirus

Back 10

RNA virus that contains the enzyme, reverse transcriptase, ex: HIV

Front 11

bacteriophages

Back 11

viruses that infect bacteria(ex: T phages that infect E. Coli)

Front 12

Processes by which viruses replicate

Back 12

lytic cycle, lysogenic cycle

Front 13

lytic cycle

Back 13

virus invades a host cell, produces new viruses, and ruptures (lyses) the host cell to release new viruses

Front 14

virulent viruses

Back 14

viruses that reproduce only by the lytic cycle

Front 15

lysogenic cycle

Back 15

virus inserts its genome into the host cell's DNA for days, months, or years. This does not harm the host cell.

Front 16

temperate virus

Back 16

virus whose replication includes the lysogenic cycle

Front 17

rapid mutation of viruses

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(influenza virus, and HIV) genetic mutations that can change the proteins on their surface, making it difficult for the immune system to recognize and destroy the virus, and making it difficult to make vaccines

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vector

Back 18

an intermediate host that transfers a pathogen or a parasite to another organism (for viruses includes humans, animals, mosquitoes, ticks and fleas; ex: West Nile virus, yellow fever virus)

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oncogenes

Back 19

genes that cause cancer by blocking the normal controls on cell reproduction

Front 20

emerging diseases

Back 20

illnesses caused by new or reappearing infectious agents that typically exist in animal populations, often in isolated habitats, and can infect humans who interact with these animals (ex: Ebola virus- hemmorrhagic fever)

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Prevention and treatment of viral illness

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1. vaccination
2. vector control
3. drug therapy
(best methods 1 and 2)

Front 22

inactivated viral vaccine

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virus not able to replicate in the host

Front 23

attenuated viral vaccine

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weakened form of the virus that cannot cause disease, provides greater protection against disease

Front 24

Virods

Back 24

smallest known particles that are able to replicate; made up of a short, circular single strand of RNA that does not have a capsid; infect plants

Front 25

Pirons

Back 25

infectious protein particles that do not have a genome; abnormal forms of a natural brain protein that appear to convert normal brain proteins into prion particles (mad cow disease, scrapie in sheep, Creutzfeldt-Jackob disease, kuru)