FINAL EXAM P3

Question 1

viruses that infect eukaryotic hosts

Answer 1

infect yeasts, plants, and animals
can be enveloped or non enveloped
most viruses are lytic and few cause cancer

Question 2

tumor cells division

Answer 2

aka transformation

over time, cancer cells may differentiate and turn into tumors

Question 3

latent infection

Answer 3

may reproduce and release particles for a while, but it may go quiet, meaning it isn’t actively reproducing, but it’s still there
at a later date it can revert back to the lytic infection =, increasing viral particles and killing the cell (chicken pox and shingles)

Question 4

retroviruses

Answer 4

contain 2 copies of identical single stranded RNA carried in its virus particle. the RNA is enclosed within a capsid. is an envelope virus

Question 5

what is an envelope virus

Answer 5

one that is surrounded by a membrane containing proteins
a virus goes through persistent infections. rather than lyse, they bud out of the surface of the cell and take a little membrane with it. the viral membrane fuses with the host cell, dumping the nucleocapsid into the cell. after replication, you end up with many copies of the nucleotide. exits via the nucleocapsid budding out of the membrane
the envelope is derived from the host cell membrane
also releases reverse transcriptase

Question 6

reverse transcriptase enzyme

Answer 6

copies the RNA and makes the 2nd complementary strand, making a dsDNA copy. this goes into the cell nucleus and integrates itself into one of the host chromosomes
retrovirus inserts its DNA into the chromosome
HIV (causes AIDs)

Question 7

retrovirus

Answer 7

carries viral enzymes:
reverse transcriptase inside the viral particle
integrase
protease
these enzymes are not found in human cells

Question 8

protease

Answer 8

specifically cleaves the HIV proteins in their functional forms
is a unique drug target because these are proteins not normally found in human cells. people with HIV infections often don’t develop AIDs or pass the virus along

Question 9

viral spike proteins

Answer 9

involved in host cell regeneration

Question 10

unique replication process of retrovirus

Answer 10

starts as ssRNA, then to ssDNA, then to dsDNA, then integrates into the host genome, then produces ssRNA and other proteins

Question 11

HIV infection

Answer 11

follows a particular pattern
immediately after infection, it spikes up to 10^6. the number of CD4T cells has a normal range of 500-700. it stays normal for 24 months. HIV is infecting and reproducing, but not killing the cells. you are relatively symptom free. for the next 2-3 years, you may experience swollen lymph nodes. the number of HIV is rapidly increasing and decreasing. it will eventually slowly start killing the T cells. its the failure of your immune system that kills you. when you are immune deficient, you’re more susceptible to other infections. could even lead to cancer development

Question 12

T cells

Answer 12

are important for combatting infectious diseases, like HIV

Question 13

opportunistic infections

Answer 13

include fumbled pneumonia

Question 14

system immune deficieny

Answer 14

is when your immune system is not functional anymore

Question 15

anti HIV drug cocktails

Answer 15

detect the initial burst of HIV dropping it to near 0 so that it’s not destroying the immune system
people are relatively non-infectious

Question 16

influenza

Answer 16

-RNA virus, complement of mRNA
genome is in 8 separate segments of -RNA all packaged within one particle
immunity is via antibodies against surface proteins. our immune system targets the spike (surface) proteins neuraminidase and hemagglutinin

Question 17

issue with influenza vaccines

Answer 17

there are so many strains and movement between the virus and the host
allows different strains to exchange genes and modify their genetic makeup of N and H alleles
antigenic shift may cause no more recognition of antibodies from a previous infection vaccination

Question 18

antigenic shift

Answer 18

very rapid, instantaneous change
genomes eat separate RNA particles and while its replicating and packaging, can lead to random selection between the particles forming new strains
COVID cannot be shuffled between viruses

Question 19

coronaviruses

Answer 19

+RNA
has extremely large genomes
one single, very large RNA molecule
can be found in virtually all mammals and birds, but generally stays in one species
is a helical nucleocapsid and enveloped with its own spike proteins
first gene in the mRNA encodes RNA replicase. it doesn’t have to make the full length of the +RNA, it can make sub length that are smaller RNA that make viral proteins

Question 20

viroids

Answer 20

infectious RNA molecules
don’t package cells and are never found outside of the host cell
is circular, ssRNA. it would look linear under a microscope because the 2 sides of the circle are complementary and base pair with each other, causing it to collapse and appear as a linear double strand
this RNA doesn’t encode any proteins. it’s able to evolve and replicate via a host enzyme, traveling from one cell to another via pores or insect vector
hard to produce a drug since there are no proteins

Question 21

examples of viroids

Answer 21

coconut cadang cadang, citrus exocortis