Week 5 Flashcards
What are drugs?
Drugs are substances that cause physiologic effects in the body.
What are the steps that a drug goes through a body system? AKA Pharmacokinetics?
1) Absorption (e.g small intestine)
2) Distribution (Drug Allocation)
3) Metabolism (e.g. liver)
4) Excretion (e.g. feces)
List the routes of administration of drugs:
Oral, intravenous (IV), intramuscular (IM), intrathecal, rectal, and transdermal routes.
What is a drug’s bioavailability?
Bioavailability describes how much of a drug reaches the bloodstream, which can be influenced by the route of administration.
True/False: the anti-cancer drug Tamoxifen is one of those drugs that needs to be metabolized in order to be physiologically active.
True
If _______ is what the body does to the drug, then _______ is what the drug does to the body.
Pharmacokinetics, Pharmacodynamics
What is the difference between drug potency and efficacy?
Potency is a measure of the amount of drug required to reach a desired effect, whereas efficacy is the maximal response achieved by a drug at any dose.
The _______ measures differences between minimal effective plasma drug concentrations and minimal toxic plasma drug concentrations.
Therapeutic window
The ______ is a ratio of the median dose that produces a toxic effect to the median dose that produces a desired effect.
Therapeutic index TI
The resting membrane potential describes the potential difference across a membrane in between ________.
Action potentials
Dose required to maintain steady state in continuous infusion of medication: _______
Maintenance dose.
Maintenance and loading dose depend on factors: 1) ______ 2) _____ 3)_____
1) Bioavailability
2) Clearance rate
3) Vd (Volume of distribution)
All viruses have some sort of genetic code, either DNA or RNA, and a protein coat called a _____.
Capsid
How are viruses separated into 3 classes?
1) DNA viruses
2) RNA viruses
3) Retroviruses
Name some examples of DNA viruses you may encounter.
dsDNA viruses: Adenovirus, viral conjunctivitis, poxviruses
ssDNA viruses: Parovirus B19
True/False: Antisense ssRNA is equivalent to mRNA.
False it is Sense ssRNA that is.
Name some example of RNA viruses you may encounter.
Rabies, measles, and Ebola
dsRNA virus: Rotavirus
Retroviruses are ___ ssRNA viruses. Most famous of these is ___.
(+) ssRNA (exclusively ssRNA! does not include dsDNA-RT)
HIV
Retroviruses have the enzyme ______, which transcribes their RNA into DNA.
Reverse Transcriptase
What are the 6 steps of a viral infection of a cell?
1) Attachment
2) Penetration
3) Uncoating
4) Replication: DNA viruses replicate in nucleus, and RNA viruses EXCEPT influenza replicate in cytoplasm.
5) Assembly: New viral nucleic acids, enzymes, and proteins assemble to form new visions.
6) Release
A virus will ceaselessly find its way into a cell, how it does that is through targeting _____.
Receptors!
HIV will target ______ co-receptors presented on CD4 cells.
CCR5 and CXCR4
Cytomegalovirus targets host _______ and ______ located on many host cells.
Glycoproteins and integrins
2 mechanisms for virus to get into the cell: 1) ______ and 2) ______
1) Receptor-mediated endocytosis
2) Fusion of the viral envelope with the cell membrane, releasing the capsid into the cell.
How would (-) ssRNA viruses replicate?
Most must introduce an enzyme called RNA replicase which forms (+) ssRNA which can function like the RNA of (+) ssRNA.
Exceptions of the rule! Poxvirus (dsDNA virus) replicates in the _____, while influenza, a ssRNA virus, replicates in the ____.
Cytoplasm
Nucleus
Where do DNA viruses and RNA viruses generally replicate?
DNA viruses replicate in host nucleus
RNA viruses replicate in cytoplasm.
Generally….
Retroviruses not only use the Reverse Transcriptase enzyme to form DNA intermediates, but they also use an enzyme called ______ to integrate DNA intermediates into the host genome.
Integrase
Which viruses use host membranes as their envelopes through viral budding?
Influenza and respiratory syncytial virus (RSV)
What is the difference between a persistent and a latent infection?
A persistent infection is symptomatic for a prolonged period, such as Hep B. A latent infection is asymptomatic unless reactivated by a trigger.
How could a virus benefit from causing inflammation?
If a virus is tropic for white blood cells, inflammation would bring more potential host cells nearby.
Which class of DNA virus is NOT double stranded (give an example)?
ssDNA –> Parvoviridae the only clinically relevant ssDNA virus. It’s so small, that its clothes don’t fit, so it is a “naked” virus.
Can viruses have their own RNA Polymerase?
Yes!
Most DNA viruses have ____ DNA, though there are some viruses that have _____ DNA.
Linear
Circular
Alternatively, naked DNA viruses will ____ the host cell to cause release.
lyse
Cytomegalovirus (CMV) presents in patients with such symptoms as pneumonia, ______, and _____.
Esophagitis, and retinitis.
What are the three classes of RNA viruses, based on the structure of their genetic material?
dsRNA, (+) ssRNA, and (-) ssRNA
Positive sense single stranded RNA viruses contain RNA that can be ______ translated by a host cell.
Directly
Analogous to mRNA
How does the RNA of (-) ssRNA viruses differ from that of (+) ssRNA viruses?
Negative-sense single stranded RNA (-) ssRNA have RNA that is complimentary to the translatable mRNA. The (-) ssRNA is a complimentary sequence that needs to be transcribed before it can be used for protein synthesis.
So how do (-) ssRNA viruses synthesize proteins if human cells do not contain RNA polymerases that transcribe RNA?
They have their own RNA-dependent RNA polymerase! Once that occurs, host ribosomes are able to translate it into protein used for viral replication.
At what step is the viral capsid degraded by viral or host enzymes and the viral genetic material released?
Uncoating
Viral RNA polymerases do not have ______ abilities like DNA polymerases, resulting in very high mutation rates.
Proofreding
Replicated viral genome and newly synthesized proteins are packaged to create active virus particles called ____. ________ also occurs during assembly.
Virion
Protein modification
Where in the host cell do most RNA viruses replicate?
Most RNA viruses replicate in the cytoplasm of the host cell. The exceptions are Orthomyxoviridae and Retroviridae, which replicated in the nucleus.
Some (-) ssRNA viruses have segmented RNA, in which their genome is spilt into multiple, smaller pieces. Usually each segment codes for a single protein and can be exchanged between viruses through a process called: ______
Reassortment
What two structural characteristics are shared by all (-) ssRNA viruses?
All (-) ssRNA viruses are enveloped and have a helical capsid.
All (+) ssRNA viruses have a(n) ______ capsid and ____RNA.
icosahedral and linear RNA
Which step of viral replication does maraviroc act on?
Acts on entry/fusion step of replication, and it is one of the drugs considered for antiretroviral therapy.
For HIV to enter a host cell, it must bind to a receptor on the surface and then fuse. One of these receptors is CCR5. ____ blocks CCR5, which prevents binding of the virus, causing it to be unable to enter the cell.
Maraviroc (drug)
How does HIV bind to the CD4 molecule?
Use of gp-120 to CD4 + co-receptor (CXCR4 and CCR5)
________: inhibit reverse transcriptase, chain terminators.
Nucleotide/nucleoside reverse transcriptase inhibitors (NRTIs)
________: inhibit reverse transcriptase rendering the elongating DNA strand incomplete and useless. They bind directly to reverse transcriptase, inactivating it. Stop DNA Polymerase from polymerizing.
Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
What is the mechanism of action of protease inhibitors?
Viral protease cuts polyprotein chains into functional units, and protease inhibitors stop this final step of viral replication.
Why is Type A influenza the most common and severe type?
Able to mutate its H and N glycoproteins during replication.
Name the two glycoproteins present on Type A and Type B Flu viruses?
1) Hemagglutinin and 2) Neuraminidase
What is the glycoprotein found on Type C flu virus?
Hemagglutinin esterase-Fusion
Compare Antigenic Drift vs. Antigenic Shift.
AD: Slight changes in genes leads to slight changes in surface proteins.
AS: Major changes, where there is mixture of genes in host leading to Reassortment, which will lead to NEW Hemagglutinin and NEW Neuraminidase.
In Influenza viruses, do we need to have RNA Polymerase?
Yes. To change to +ssRNA
True/False: Both vaccines TIV and LAIV are trivalent.
True
Two types of treatment for Influenza include 1)_____ and 2)_____.
1) Neuraminidase inhibitors; H1N1 commonly resistant
2) M2 proton channel inhibitor; active against Type A only
CTLA-4 will ______ bind to B7 to prevent _____ binding. It actually has more affinity for B7!`
Competitively bind
prevent CD28
In B cell activation, B cells CANNOT activate without input from _____.
T cells
Cell surface ligand CD45 is helpful in determining various types of T cells. In CD45RA vs. CD45RO, how can you tell which is naive and which is the effector?
CD45RA will have all subunits, not spliced
CD45RO has only their exons! They know what they’re looking for, and are ready to attack.
During competitive inhibition, we can expect the Km to ____.
be high/increase
What happens if there is a mutation in the co-receptor of a CD4 T cell when binding to HIV?
1) If Homozygous, you will have resistance/immunity, since the virus cannot bind to the cell. Get no HIV
2) If Heterozygous, you will just have a slower disease progression, but still get the disease.
