Biology Chapter 24 – Viruses – Flashcards
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What is a virus?
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Non-living particle made up of nucleic acid and capsid
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Is a virus a cell?
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No
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Are viruses considered living?
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No
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What are the 4 main reasons viruses don't qualify as living?
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1. No cells, 2. Doesn't occur through mitosis, 3. Must be inside the host, 4. Doesn't maintain homeostasis through metabolic reactions
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How does a virus use its host cell to reproduce?
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Use host's enzymes and organelles
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Name 5 diseases caused by viruses:
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Adeno- Respiratory infections, Herpes- Cold and genital sores, Pox- Small pox, Picorna- Polio, hepatitis, colds, Retro- AIDS, leukemia
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Why don't viruses work with antibiotics?
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They aren't living and only work on bacteria
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What is a retrovirus?
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Contains RNA and reverse transcriptase
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What is a prion?
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Infectious protein particle with no genome
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What is an example of a disease caused by a prion?
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Mad Cow Disease
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How are the majority of viruses spread to others?
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Air, water, and vector
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Why do viruses have to be intracellular parasites?
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Viruses are lifeless without them
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What types of nucleic acid are in viruses?
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DNA and RNA
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What does reverse transcriptase do?
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It uses RNA as a template to make DNA
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What is a capsid composed of?
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Proteins or lipids
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What are the two lifecycles exhibited by a virus?
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Lytic and lysogenic
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During which lifecycle does the host become sick?
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Lytic
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During which lifecycle does the host become infected with the virus, but doesn't get sick?
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Lysogenic
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A person comes to the doctor with a cold sore. The patient complains that they come and go. Sometimes, there are periods of outbreaks of cold sores between months. What does he have?
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Temperate virus- Viral replication becomes lytic
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Viruses that infect bacteria are called:
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Bacteriophages
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Viruses can be seen with a --- microscope.
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Transmission-electron
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Viruses can cause damage to ---.
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Living organisms
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Each kind of virus infects --- hosts.
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Specific
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Viruses are --- than the cells they infect.
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Smaller
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Viruses reproduce --- of living cells.
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Inside
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Viruses --- the cells in which they live.
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Harm
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The study of viruses is a part of biology because:
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Cause diseases in living organisms and continue genetic research
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The capsid of the virus is the:
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Only layer surrounding some viruses
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Viruses are classified according to:
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DNA or RNA, single or double stranded, linear or circular, nature of the capsid, and presence of the envelope
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Tobacco mosaic virus has what kind of shape?
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Helical
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Scientists first began to study viruses because:
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Smaller factor than bacteria causes disease
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Animals viruses often infect only specific host cells because:
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They have specific receptors for glycoprotein on the virus
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Viroids contain only:
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RNA (no capsid)
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What is an example of a retrovirus?
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HIV
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What are vectors?
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Intermediate hosts that transfer pathogens or parasites to an organism
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What has been the most successful at fighting viral disease?
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Vector control and vaccination
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Most scientists believe viruses originated from:
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Early cells
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HIV causes AIDS by:
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Spreading with sexual contact
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Viruses linked to cancer:
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HPV, Hepatitis B, HTLV, and EBV
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Common viral diseases in humans:
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Flu, chickenpox, measles, polio, and hepatitis
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When viral replication includes the lysogenic cycle, the virus is called:
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Temperate
