kingdoms, viruses, pathogens Flashcards
do bacteria have chloroplasts
no
Transcription/translation occurs in same compartment of ___ everyone else does it in diffferent compartmetns
bacteria. note that even protists do transcription and translation in diff compartments
what component is in cell walls
peptidoglycan
flagella in eukaryotes vs bacteria
9+2 for cilia /flagella in eukaryotes, protists, plantae. Bacteria have their own special flagella- rotary motor
three domains of living things
bacteria, archae, eukarya
Pathogen
something that causes a disease
Archaea
primitive type cells. Different enough that they are NOT closely related to other bacteria- but they ARE prokaryotes. No nucleus. Also called ‘extremophiles’ because they like to live in hot springs, glaciers, etc. no effect on health/disease. Own kingdom.
explain how ancestral eukaryotes evolved
an archae type picked up a mitochondria . Gives rise to fungi, animalia, etc. the archae that picked up photosynthetic bacteria became chloroplasts-> plants, protists
how many kingdoms are there
6
why are viruses not living?
They MUST be inside of a host cell to replicate- cannot do it on their own.
- Have no metabolism
- No oxygen consumed, no ATP used, etc
lifecycle of a phage- lytic vs lysogenic?
- Once DNA has been injected, could go a couple of ways
- Lytic cycle: take over cell right then and immediately start transcribing/translating viral genes. breaks open host cells
- Lysogenic cycle: turn off repressor proteins, repressor protein says ‘don’t break open!’- has potential to be converted back into viral factory stage. Has potential to break open and produce new virus.
replication cycle DNA virus
1) Attachment (Adsorption)
2) Penetration
3) Uncoating
4) Targeting
5) Gene expression.
- synthesis of viral mRNA (transcription)
- synthesis of viral proteins (translation)
6) Genome replication
7) Virion assembly/maturation
8) Release of new infectious virus
- lysis : breakdown of cell membrane and release of virus
- budding: viruses “bud” through cell membrane and are released without necessarily killing the cell. Viruses acquire envelopes (membranes) during this process.
Replication cycle for RNA virus
- Carries its own reverse transcriptase- so it can copy its own RNA and animal cells do not have any reverse transcriptase in them
- Note: reverse transcriptase critically important in cloning as it creates cDNA. It’s the only enzyme that will use RNA as a template. Howard Temin + David Baltimore Nobel prize for this.
- Binds 2 cell. HIV viruses only attack T-cells. Have marker on surface called CD4. It’s the surface marker that hiv viruses recognize in order to bind to target cells.
- Copy RNA into double stranded dna. Why? Much more stable
- Double stranded dna inserts itself DIRECTLY INTO GENOME OF HOST CELL.
Once in host genome; transcription of DNA produces RNA’s that are the genome for an RNA virus. Same RNA gets translated by ribosomes and makes viral proteins, assemble new viruses, and then bud out.
difference between DNA virus vs RNA virus replication: genome
DNA virus not incorporating itself into genome
why do RNA viruses carry their own reverse transcriptase with them?
so it can copy its own RNA- animal cells do not have any reverse transcriptase in them
what marker would you use to test for HIV?
CD4
mutation in CCR5 protein- what is it and what does it lead to?
no functioning CD4 receptor for the virus to hook onto- totally HIV resistant (if homozygous)
common tests for HIV
- t-cell count
- virus titer (count # viruses)
- western blot (southern blot with proteins) use anti HIV antibiotics to detect gp120 (envelope protein) sits on surface. Direct test for nucleic acid.
- Can also detect patient antibody against gp120: if they’re making antibody, it means they have been exposed
treatment for HIV
- AZT- azidothymadine- form of nucleotide that is dideoxy- has an amino group instead of 3’ OH group. Synthesis of DNA will STOP at dideoxy. Just like it did in some sort of sequencing reaction we were discussing.
- The reason it is so efficient at interrupting the RNA virus is that Reverse transcriptase has a higher affinity for AZT (as opposed to normal thymine) azt is just a mutated form of thymine.
what is combination therapy for HIV?
AZT + protease inhibitors (prevent resistance to AZT) . inhibits manufacture of new HIV viruses
three types of bacteriophages
Lamba phage , T2, T4
list out some common manifestations of the herpes virus (DNA) group
herpes, cold sores, chicken pox, epstein barr,
cancer causing (DNA) viruses?
HHV, karposi’s sarcoma. Also cervical cancer comes from papilloma virus.
give some examples of RNA retroviruses
HIV, polio, yellow fever
rabies/mumps/measles/flu/ebola/hep C- all what type of virus?
RNA virus
herpes: RNA or DNA virus?
DNA
influenza: DNA or RNA virus?
RNA
prion diseases
brain issues- proteins fold into the wrong shape- due to infection via prion, which is NOT a virus but behaves like one
