lecture 4 Flashcards
(44 cards)
what is a virus and what is it made up of
a virus is a obligate intracellular parasite and it is made up of protein (capsid) and nucleic acid (genome)
what are the two basic steps of the viral life cycles and define them
- Attachment or Adsorption: it specifically binds to cell surface marker and host has yet to be infected
- Injection or Penetration: virus propels its genome into host and host is now infected
what is the speed of the lytic life cycle of a virus? what are the steps
the speed is very quick and it kills host too quickly.
the steps: 1. transcribe and translates the viral genome
2. creates pool of DNA building blocks or dNTPs to be used to replicate the viral genome
3. replicate the viral genome
4. lysis of host and release of new viral particles
what is the speed of the lysogenic cycle of a virus? what are the steps
this process takes longer and it doesnt kill the host
1. integrate viral genome with host genome
2. host cell activity continues to allow more reproduction of viral DNA
3. if cell is under stress (it will die), the virus may excise itself (leave) and it is required for the repressed gene to turn off.
what is transduction in viral reproduction
transfer of host DNA to new host via lysogenic virus
what is the productive cycle
this is similar to the lytic cycle but without the lysis. there is budding (exocytosis) and can only occur with animal cells as they do not have cell walls. the virus becomes enveloped with host membrane to avoid immune system detection.
what are the advantages to the productive cycle? the disadvantages?
advantages: 1. more viral particles are produced bc no cell death 2. envelope allows to evade immune system 3. easier infection because virus taken up as a whole
disadvantages: no DNA building blocks
what is +RNA and what can it do?
it is mRNA and due to this, it can immediately be translated using hosts RIBOSOMES
what does +RNA NEED to code for
RNA dependent which reads RNA and RNA polymerase which makes RNA
what is -RNA and what can it do?
Negative-sense viral RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA polymerase before translation
what are prions and how can they occur
prions are infectious misfolded proteins that have NO dna or rna or any organelles or anything like that because theyre proteins. they can occur by inheritance, injection, or arise from a mutation in a gene
what are the two types of prions
normal prions: have neuroprotective effect and mutant prions: cause neuro holes
what are viroid’s and how do they replicate
viroids are circular RNA with no capsid proteins and MUST be coinfected with a virus, they do not code for any proteins and they act as a miRNA and siRNA to block translation. they replicate by circularizing host RNA
what is a round shaped bacteria called
coccus
what is a rod shaped bacteria called
bacillus
what is a spiral shaped bacteria called
spirochet or spirellum
what is the suffix for a flagella
trichous
what is the suffix for one flagella? multiple? one on each side of bacteria?
one flagella is monotrichous, multiple is peritrichous, one on each side is amphitrichous
what is bacterial cell wall made up of
glycoprotein
what is the periplasmic space and what is an important charcateristic
this space is all the membranes surrounding the cytosol and holds Antigen degenerative enzymes
gram +
stains dark purple , bacteria has thick cell wall and staining binds to petidoglycan
gram -
stains lighter pink, they are more antibiotic resistant than gram positive
what are bacteria living in medium temps, hot temps, and cold temps
medium temps: mesophiles
hot temps: thermophiles
cold temps: psychrophiles
what is a bacteria that uses oxygen called
obligate aerobe, without oxygen they die
