Walters-BSC2010-Chapter19-10

Walters-BSC2010-Chapter19-10 - Chapter 19: Viruses (Test:...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 19: Viruses (Test: Topics discussed in lecture, including diseases)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Bacteria and Viruses Bacteria prokaryotes, no nucleus Viruses biologically inert can not reproduce independently obligate intracellular parasites don’t fit our definition of living organism
Background image of page 2
Viruses Called particles, not cells Aggregate of nucleic acids (genome) and protein coat (capsid) Called DNA or RNA virus Single molecule of genetic material: linear or circular Contains 4 to few 100 genes Bacteriophage
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Viral genome possibilities : (you do not need to memorize examples) Double-strand DNA (e.g. warts, herpes, mononucleosis, chicken pox) Single-strand DNA (e.g. roseola) Double-strand RNA (e.g. diarrhea, respiratory) Single-strand RNA (e.g. HIV, rabies, measles, common cold, encephalitis) Measles Herpes Measles
Background image of page 4
Viruses Protein shell = capsid Protein subunits called capsomeres Structure: rod-shaped, polyhedral, complex Membrane covers SOME capsids = viral envelope , derived from host cell membrane. Also contain proteins & glycoproteins of viral origin.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Fig. 19.3
Background image of page 6
Viral reproduction: Only reproduce within living cells Each virus has specific host range host range: host cells that a virus can infect lock & key fit between external viral proteins and host cell receptor sites broad host range: rabies narrow host range: phages on E. coli , AIDs on certain white blood cells
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
General Life Cycle of DNA Virus Infect host with viral genome Once inside takes over host’s resources replicate viral genome (DNA replication) make capsid proteins (transcription, translation) Assemble new viruses Release new viruses, host usually destroyed
Background image of page 8
Fig. 19.4
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Bacteriophages: Reproduction Details Most understood type of virus Hershey/Chase used bacteriophages to determine DNA was the genetic material 2 alternative mechanisms: Lytic cycle and Lysogenic cycle
Background image of page 10
Lytic cycle Ends with death of host cell If reproduce only this way = virulent virus In bacteria, cycle takes 20 - 30 min at 37 degrees C, increase population 100X each time
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lytic cycle (7 steps): (1) Phage attaches to cell surface (complimentary fit) (2) Phages injects DNA
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/19/2011 for the course BSC 2010c taught by Professor Janewaterman,pamelathomas during the Spring '07 term at University of Central Florida.

Page1 / 35

Walters-BSC2010-Chapter19-10 - Chapter 19: Viruses (Test:...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online