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Questions and Answers
What is the primary reason for seeking compounds that are converted to triphosphates in greater amounts in infected cells compared to normal cells?
What is the primary reason for seeking compounds that are converted to triphosphates in greater amounts in infected cells compared to normal cells?
- Normal cells synthesize DNA and RNA at a lower rate. (correct)
- Normal cells are more efficient in utilizing energy.
- Infected cells utilize oxygen more effectively.
- Infected cells have a higher demand for nutrients.
Which statement is true regarding the synthesis of DNA and RNA in normal versus infected cells?
Which statement is true regarding the synthesis of DNA and RNA in normal versus infected cells?
- Infected cells generally do not require DNA and RNA synthesis.
- Normal cells synthesize DNA and RNA actively to fight infections.
- Compounds that become triphosphates are needed to enhance synthesis in infected cells. (correct)
- Both cell types require the same level of triphosphate for DNA and RNA synthesis.
What characteristic of infected cells justifies the search for specific compounds that lead to increased triphosphate production?
What characteristic of infected cells justifies the search for specific compounds that lead to increased triphosphate production?
- Infected cells convert compounds to triphosphates more efficiently. (correct)
- Infected cells have a disrupted metabolic process affecting triphosphate synthesis.
- Normal cells primarily focus on lipid synthesis rather than nucleic acids.
- Normal cells require fewer triphosphates for metabolic activities.
Which of the following compounds is likely to be prioritized for development based on the synthesis rates in infected cells?
Which of the following compounds is likely to be prioritized for development based on the synthesis rates in infected cells?
Why is it advantageous for compounds to be more effectively converted to triphosphates in infected cells?
Why is it advantageous for compounds to be more effectively converted to triphosphates in infected cells?
What characteristic of nucleosides makes them desirable for treating viral infections?
What characteristic of nucleosides makes them desirable for treating viral infections?
What is the primary benefit of nucleoside selectivity for viral kinases?
What is the primary benefit of nucleoside selectivity for viral kinases?
Which of the following statements best reflects the concept of selective toxicity in nucleosides?
Which of the following statements best reflects the concept of selective toxicity in nucleosides?
Why is higher selectivity for viral kinases desired in nucleoside treatments?
Why is higher selectivity for viral kinases desired in nucleoside treatments?
Which factor is crucial for determining the effectiveness of nucleosides in antiviral therapies?
Which factor is crucial for determining the effectiveness of nucleosides in antiviral therapies?
Flashcards
DNA and RNA Synthesis
DNA and RNA Synthesis
The process of creating DNA and RNA molecules.
Triphosphates
Triphosphates
The active form of compounds used in DNA and RNA synthesis.
Infected Cells
Infected Cells
Cells that are infected with a virus or other pathogen.
Normal Cells
Normal Cells
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Seeking Compounds for Selective Toxicity
Seeking Compounds for Selective Toxicity
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Nucleosides
Nucleosides
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Kinase
Kinase
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Selective Toxicity
Selective Toxicity
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Higher Affinity
Higher Affinity
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Idoxuridine
Idoxuridine
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Study Notes
Phosphorylation
- Phosphorylation is the addition of a phosphoryl (PO3) group to a molecule.
- This is vital for cellular storage and energy transfer in biological systems.
- Energy carrier molecules are used in this process.
- Phosphorylation produces high-energy phosphodiester bonds, such as those in ATP and GTP.
- The body uses these molecules to phosphorylate other molecules, which activates them.
Phosphorylation and DNA/RNA Synthesis
- Phosphorylation introduces a leaving group, which can be displaced by an incoming nucleophile.
- This is seen in DNA and RNA synthesis, where nucleotides are added to the 3' end of a growing DNA or RNA chain.
Antiviral Agents
- Phosphorylation is often required for the activation of antiviral agents.
- These agents are often nucleosides that must be converted to nucleotides to be active.
- Antiviral agents commonly disrupt DNA or RNA synthesis, typically by converting them to triphosphates.
- Some antiviral agents are designed to target viral kinases more effectively than mammalian kinases for increased selectivity and reduced toxicity to healthy cells.
Idoxuridine
- Idoxuridine is a prodrug that shows clinical effectiveness against viruses.
- Idoxuridine has higher affinity for viral kinases than mammalian kinases, making it more selective against viruses.
- Idoxuridine enters virally infected cells and is phosphorylated preferentially by viral thymidine kinase, making it a superior substrate.
- Following phosphorylation, it can inhibit viral DNA synthesis.
- This can happen through several mechanisms including inhibiting viral DNA polymerase.
- It can disrupts the ability of viral DNA/RNA as a template molecule by incorportating into viral DNA, resulting in incorrect base pairing.
- Idoxuridine is generally lipid soluble.
Methenamine
- Methenamine is a prodrug used for urinary tract antiseptics, functioning as a source of formaldehyde.
- The low pH of the urine promotes the hydrolysis to formaldehyde, the active antibacterial agent.
- Methenamine serves as a substrate for the enzymes involved in phosphorylating processes in viruses.
- The phosphorylated forms of the antiviral agents are the active form.
Site-Specific Drug Delivery
- Site-specific drug delivery is often used with drugs having narrow therapeutic windows (e.g., anticancer drugs).
- High metabolic activity in organs like the liver and kidneys offers an advantage for drug delivery.
- The rate of conversion from prodrug to active drug at target sites should be greater compared to other areas to limit toxicity.
- There should be a slow migration of the active drug from target sites to minimize any side effects that may occur after the drug is no longer needed.
- Various carrier systems have been considered to aid drug delivery, including proteins, polysaccharides, liposomes, and implemented mechanical pumps.
Basic Goal of Chemical Drug Delivery Systems
- The goal is to protect a drug from the non-specific biological environment where it may be rendered inactive before it reaches its target, and to protect a non-specific environment from the drug to prevent unintended harm to healthy cells.
- This concept is vital for drugs with a narrow therapeutic window, particularly anti-cancer agents.
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