Module 5 Flashcards
What are the two main structures of viruses
naked virus
enveloped virus
what are the 2 main types of viruses
RNA and DNA
What are the 3 ways RNA viruses replicate
Direct translation
Virus has its own viral RNA polymerase
Reverse transcription
Describe direct translation
ss RNA or one strand of dsRNA acts as mRNA and is translated in the cytoplasm by host machinery
ie. Rubella
Describe virus replication when virus has its own RNA polymerase
Genetic material comes in as ssRNA and uses its own RNA polymerase to make a copy that acts like mRNA and can be translated
ie. influenza
describe reverse transcription
virus RNA enters cell cytoplasm, reverse transcriptase from the virus makes a copy of the RNA into DNA
then integrated into host DNA and the virus DNA is transcribed/transcripted just like normal host proteins
ie. HIV (retrovirus)
Describe DNA virus
can be ssDNA or dsDNA that enters cell and goes to nucleus, transcribed by host cell machinery or virus enzyme to form mRNA, host cell machinery translate protein
ie. HSV 2
What is the virus life cycle
infecting virus
attachment
penetration
uncoating
replication
assembly
release
what are the 4 possible outcomes of viral infections
lytic
persistant
latent
cancer
describe lytic viral infection
when virus assembles, cell breaks open and cell dies
describe persistant viral infection
virus keeps using the cell to assemble and buds off
doesnt destroy cell
describe latent viral infection
HSV 1/2
remain dormant in neurons until reactivated
describe cancer caused by viral infections
15% of all human cancers are attributed to viruses
doth DNA and RNA viruses
DNA: EBV, HPV, Hep B and human herpes virus-8
RNA: Hep C, Human T lymphotrophic virus type 1
describe a prokaryote
No organelles except for ribosomes
cell membrane is covered by peptidoglycan cell wall and in some an outer cell wall membrane
has DNA in plasmids not nucleus
some have flagella
smaller than eukaryote
divide through binary fission
describe a eukaryote
has organelles
has single plasma membrane, yeast have chitin wall
DNA in chromosomes in nucleus
can have flagella
larger than prokaryote
divide throgh mitosis
Describe the structure of gram positive bacteria
no outer membrane
thick peptidoglycan
has plasma membrane
describe structure of gram negative bacteria
outermembrane of LPS and lipoprotein
thin peptidoglycan
has plasma membrane
how is the plasma membrane of bacteria same/different from that of eukaryotes
SAME: pores for transport, enzymes, receptors
DIFFERENT: no mitochondria –> PM acts in ETC and oxidative phosphorylation, excretes hydrolytic exoenzymes
describe peptidoglycan
a polymer of sugars and amino acids that form mesh layers outside the membrane (cell wall)
describe pili
transfer DNA between bacteria, motility and attachment sites
describe teichoic acid
add rigidity to cell wall, recepetors for some bacteriophages, function in pathogenesis
describe the capsule
polysaccharide layer on the outermost edge of bacteria, function in adherence and protection
describe plasmids
circular genetic elements that reproduce autonomously and exist outside the normal DNA
what is a bacteriophage
a virus that infects prokaryotic cells (infects bacteria)
