Lecture 5 Flashcards
epidemic: the occurrence of more cases of disease than expected in a given … or among a … over a particular period of time
area; specific group of people
pandemic: an epidemic occurring over a … (several countries or continents) and usually affecting a … of the population
very wide area; large proportion
influenza type … is responsible for annual ..
A; epidemics
Influenza type A is responsible for devastating pandemics:
1918 …
1957 …
1968 …
spanish flu; asian flu; hong kong flu
… is caused by the influenza virus
the flu
viruses are …, … parasites
submicroscopic (cant be seen in normal microscope); obligate intracellular
virus particles are produced from the assembly of … and they themselves do not … or undergo …
preformed components; grow; divisoin
viruses lack the genetic information that encodes apparatus necessary for the generation of … or for …
metabolic energy; protein synthesis (ribosomes)
bacteriophage structure: DNA in a … with … and …
capsid; capsomere; glycoproteins
retrovirus structure: genetic info inside …, along with …., covered by a … that contains …
capsid; reverse transcriptase; viral envelope; glycoproteins
influenza is an … virus: assigned to one of the 12 families based on …, …, and nature of … genome
RNA; envelope; capsid; RNA
flu viruses are named by the type of
surface proteins
surface proteins for flu virus
hemagglutinin (H spike): trimer, helps virus ….
Neuraminidase (N spike): tetramer, helps virus …
enter cell; exit cell
flu virus named like such A/Sydney/5/97 (H3N2) the first letter is the influenza ... the second word is the ... the third number is the ... number the fourth number is the year of ... and the thing in parentheses show the hemagglutinin and neuraminidase ...
type; geographic source; isolate; isolation; subtypes
key to influenza are glycoprotein spikes (…)
hemagglutinin- .. subtypes; most important … factor; binds to …
surface proteins; 18; virulence; host cells
neuraminidase: … subtypes; hydrolyzes … and assists … and …
11; mucus; viral budding; release
an influenza virus infects a host cell when HA grips onto … on the cell surface
glycans
after influenza virus binds, the cell engulfs it by …, and the viral contents are released. Viral RNA enters the nucleus where it is … by the viral RNA polymerase. Viral mRNA is used to make viral proteins and the new viral particles are made and released into the extracellular fluid. the cell continues to make the new virus
endocytosis; replicated;
some viruses …. whereas other viruses do not
integrate their genome into the host genome
lytic cycle: the phage DNA is repicated and new phages are made. The cell then …, releasing the phages
lyses
lysogenic: the phage DNA becomes …, and the cell divides, passing …. to daughter cells. Under stressful conditions, the phage is excised and enters the lytic cycle
incorporated into host genome; prophage DNA
two categories of genetic change to surface proteins; … and …
antigenic drift; antigenic shift
antigenic drift: constant … gradually changes … composition
mutation; amino acid
antigenic shift: one of the genes or RNA strands is … with a gene or strand from another influenza virus from a ,,,
substituted; different animal host
