Title: Medicinal Chemistry Week 5 Quiz

Feedback shared by this category's questions, if partly right: 1

Q: What does a medicinal chemist usually mean by the term "drug"?
- A substance which has a marked effect on the body in order to prevent or treat disease.
- A substance taken by mouth in order to treat or prevent disease.
- An substance which is used illegally for recreation purposes.
- A substance which results in addiction and withdrawal.
A: A substance which has a marked effect on the body in order to prevent or treat disease.

Q: Which of the following binding interactions is likely to be the most important inital interaction when a drug enters a binding site?
- van der Waals interactions
- Covalent bonding
- Hydrogen bonding
- Ionic bonding
A: Ionic bonding

Q: Which of the following descriptions best describes the secondary structure of proteins?
- The arrangement of different protein subunits in a multiprotein complex.
- The order in which amino acids are linked together in a protein.
- The overall three dimensional shape of a protein.
- Regions of ordered structure within a protein.
A: Regions of ordered structure within a protein.
Feedback: Primary structure refers to the order of the amino acids in a protein. Secondary structure indicates regions of ordered structure, and tertiary structure is the overall structure of the protein. Quaternary structure refers to the structure of a multi-protein complex. Page reference: 18-19

Q: What are the relative strengths of different types of bonds?
- Covalent > H-bond > Ionic > Van der Waals.
- Van der Waals > Ionic > H-bond > Covalent.
- Covalent > Ionic > H-bond > Van der Waals.
- Ionic > Covalent > Van der Waals > H-bond.
A: Covalent > Ionic > H-bond > Van der Waals.
Feedback: Covalent bonds are strongest since they involve the sharing of electrons between two atoms. Ionic interactions are electrostatic in nature and involve interactions between opposite charges. Hydrogen bonding can be seen as a weak form of ionic interaction. Van der Waals interactions are weakest since they involve attractions between transient regions of charge. Page reference: 5-9

Q: Which of the following functional groups is most likely to participate in a dipole-dipole interaction?

[Image]
- Ketone.
- Alkene.
- Aromatic ring.
- Alcohol.
A: Ketone.
Feedback: The ketone will have the strongest dipole moment due to the electronegative oxygen polarising the carbonyl bond. The alcohol will also have a significant dipole moment, but less than that of the ketone. The alkene and aromatic rings may have small or negligible dipole moments depending on their substituents. Page reference: 9

Q: Consider the molecule in blue bound to a binding site and identify the binding interactions (i-iv) that are formed by the various parts of the molecule to the binding site.

[Image]
- i | Van der Waals interactions
- ii | Ionic bond
- iii | Hydrogen bond acceptor
- iv | Hydrogen bond donor
Feedback: Van der Waals interactions take place between regions of molecules consisting solely of carbon and hydrogen atoms. Ionic bonds occur between charges of opposite sign. Hydrogen bonds occur between a molecule acting as a hydrogen bond donor (RXH; where X is normally oxygen or nitrogen), and a molecule acting as hydrogen bond acceptor where a heteroatom is present (normally oxygen or nitrogen). Page reference: 5-9

Q: Identify the binding interactions that might be possible at the specified positions of the following drug:

[Image]
- i | Hydrogen bond donor
- ii | Van der Waals interactions
- iii | Hydrogen bond acceptor
- iv | Ionic interactions
Feedback: Van der Waals interactions take place between molecular regions consisting solely of carbon and hydrogen atoms; for example alkyl groups or aromatic rings. Ionic bonds occur between charges of opposite sign. Hydrogen bonds occur between a molecule acting as hydrogen bond donor (RXH; where X is normally oxygen or nitrogen), and a molecule acting as hydrogen bond acceptor where a heteroatom is present (normally oxygen or nitrogen). Page reference: 5-9

Q: Antiulcer drugs are an example of a group of compounds defined by which of the following classifications?
- By chemical structure
- By pharmacological effect
- By target system
- By site of action
A: By pharmacological effect

Q: What type of drug name is Ventolin (used to treat asthma)?
- Systematic (IUPAC)
- Research code
- Generic
- Proprietary
A: Proprietary

Q: Which of the following statements is true about a peptide bond (RCONHR')?
- It is planar.
- It is not capable of forming a hydrogen bond.
- The cis configuration is favoured over the trans configuration.
- Single bond rotation is permitted between nitrogen and the carbonyl group.
A: It is planar.
Feedback: 'It is planar' is correct. The peptide bond has double bond character due to the interaction of the nitrogen lone pair with the carbonyl group. This prevents bond rotation and makes the bond planar. The other options are false. The NH of the amide can act as a hydrogen bond donor and the carbonyl group can act as a hydrogen bond acceptor. The trans isomer is favoured over the cis isomer. Single bond rotation is not allowed due to the double bond character of the group. Page reference: 17-18

Q: Which of the following statements is false?
- Drug targets are normally macromolecules.
- Drugs are generally smaller than drug targets.
- Drugs are generally organic molecules.
- Drugs usually act by forming covalent bonds with drug targets.
A: Drugs usually act by forming covalent bonds with drug targets.
Feedback: Some drugs do form covalent bonds to their targets, but most drugs interact by intermolecular binding interactions. The other statements are true. Most drug targets are large molecules (macromolecules) that are far bigger than the drugs that interact with them. There are some inorganic compounds used in medicine, but the vast majority of drugs are organic molecules. Page reference: 4-5

Q: Antiulcer drugs are an example of a group of compounds defined by which of the following classifications?
- By pharmacological effect
- By chemical structure
- By target system
- By site of action
A: By pharmacological effect

Q: Which of the following statements is incorrect regarding carrier proteins?
- They are present in cell membranes.
- They serve to carry non polar molecules across the cell membrane.
- They are required to transport amino acids across cell membranes.
- They are not required to transport steroids across cell membranes.
A: They serve to carry non polar molecules across the cell membrane.
Feedback: Transport proteins carry polar molecules across the cell membrane. Non-polar molecules can dissolve through the hydrophobic cell membrane. Page reference: 27-28

Q: Which of the following descriptions best describes the quaternary structure of proteins?
- The arrangement of different protein subunits in a multiprotein complex.
- The order in which amino acids are linked together in a protein.
- The overall three dimensional shape of a protein.
- Regions of ordered structure within a protein.
A: The arrangement of different protein subunits in a multiprotein complex.
Feedback: Primary structure refers to the order of the amino acids in a protein. Secondary structure indicates regions of ordered structure, and tertiary structure is the overall structure of the protein. Quaternary structure refers to the structure of a multi-protein complex. Page reference: 23-24

Q: Which of the following statements about protein tertiary structure is false?
- Proteins fold up into a tertiary structure such that most amino acids with hydrophobic residues are exposed to the aqueous surroundings.
- Proteins fold up into a tertiary structure such that most amino acids with hydrophilic residues are exposed to the aqueous surroundings.
- Proteins fold up into a tertiary structure such that most amino acids with hydrophobic residues are in the centre and hidden from the aqueous surroundings.
- Interactions between amino acid residues are important in protein tertiary structure.
A: Proteins fold up into a tertiary structure such that most amino acids with hydrophobic residues are exposed to the aqueous surroundings.
Feedback: In general, proteins fold up such that as many hydrophobic residues as possible are positioned in the centre of the protein such that they interact with each other rather than with water. Hydrophilic amino acids can interact favourably with water and are more likely to be on the outside. Several amino acid side chains interact with each other by means of ionic and hydrogen bonding. Page reference: 19-21

Q: Identify the strongest form of intermolecular bonding that could be formed involving the residue of the amino acid phenylalanine.
[Image: phenylalanine]
- Ionic bond.
- Hydrogen bond.
- Van der Waals interactions.
- Dipole-dipole interactions.
A: Ionic bond.

Q: Identify the binding interactions that might be possible at the specified positions of the following drug:

[Image]
- ii | Van der Waals interactions
- i | Hydrogen bond donor
- iii | Hydrogen bond acceptor
- iv | Ionic interactions
Feedback: Van der Waals interactions take place between molecular regions consisting solely of carbon and hydrogen atoms; for example alkyl groups or aromatic rings. Ionic bonds occur between charges of opposite sign. Hydrogen bonds occur between a molecule acting as hydrogen bond donor (RXH; where X is normally oxygen or nitrogen), and a molecule acting as hydrogen bond acceptor where a heteroatom is present (normally oxygen or nitrogen). Page reference: 5-9

Q: Match the following terms to the descriptions.
- A hollow or cleft present on the surface of a macromolecule to which a drug can bind. | Binding site
- Functional groups on a drug which are used to bind it to the drug target. | Binding groups
- A region of the drug target which can bind to a specific functional group present on a drug. | Binding region
Feedback: The binding site is normally a hollow or cleft on the macromolecular target into which a drug can bind. Specific binding regions within that site 'recognise' specific binding groups on drugs (or ligands) to allow binding interactions to take place. Page reference: 4-5

Q: Identify the strongest form of intermolecular bonding that could be formed involving the residue of the amino acid phenylalanine.
[Image: phenylalanine]
- Ionic bond.
- Hydrogen bond.
- Van der Waals interactions.
- Dipole-dipole interactions.
A: Van der Waals interactions.

Q: Which of the following terms refers to the process by which a substrate binds to an active site and alters the shape of that active site?
- Moulded fit
- Intermolecular bonding
- Induced fit
- Lock and key theory
A: Induced fit

Q: Which of the following is false with respect to a binding site?
- It is part of a macromolecule that acts as a drug target.
- It contains binding regions.
- It is normally a hydrophiliic hollow or cleft on the surface of the drug target.
- It is usually hydrophillic in nature.
A: It is usually hydrophillic in nature.

Q: Which of the following statements is false?
- Desolvation is an energy expensive process which involves the removal of water from polar functional groups prior to a drug binding to its binding site.
- Water molecules surrounding a hydrophobic region of a drug form an ordered layer of molecules with high entropy.
- Interaction between the non-polar regions of a drug and the non-polar regions of a target require the removal of an ordered water coat and represents a gain in binding energy due to increased entropy.
- An increase in entropy results in a greater negative value of ΔG and a greater chance of binding.
A: Water molecules surrounding a hydrophobic region of a drug form an ordered layer of molecules with high entropy.

Q: What general term is used to describe large biologically important molecules?
- Polymers
- Macromolecules
- Proteins
- Oligomers
A: Macromolecules

Q: Which of the following statements is not true about receptors?
- Most receptors are proteins situated inside the cell.
- Receptors contain a hollow or cleft on their surface which is known as a binding site.
- Receptors bind chemical messengers such as neurotransmitters or hormones.
- Receptors do not catalyse reactions on chemical messengers.
A: Most receptors are proteins situated inside the cell.

Q: Which of the following statements is not true regarding the binding site of a receptor?
- The binding site is normally a hollow or cleft in the surface of a receptor.
- The binding site is normally hydrophillic in nature.
- Chemical messengers fit into binding sites and bind to functional groups within the binding site.
- The binding site contains amino acids which are important to the binding process.
A: The binding site is normally hydrophillic in nature.
  Hint: Ch4

Q: Which of the following statements best describes induced fit?
- The process by which a binding site alters shape such that it is ready to accept a chemical messenger.
- The process by which a chemical messenger adopts the correct binding conformation before entering a binding site.
- The process by which binding of a chemical messenger to a binding site alters the shape of the binding site.
- The process by which a binding site alters the shape of the chemical messenger into the binding conformation before binding.
A: The process by which binding of a chemical messenger to a binding site alters the shape of the binding site.

Q: When a membrance-bound receptors binds its chemical messenger, an induced fit takes place which leads to secondary effects, allowing a chemical message to be received within the cell. Which of the following mechanisms is not involved in this process?
- The transport of a chemical messenger into the cell.
- The opening or closing of an ion channel.
- The activation of a signalling protein.
- The activation of a membrane-bound enzyme.
A: The transport of a chemical messenger into the cell.

Q: Which of the following statements is not true?
- Neurotransmitters are released by nerves.
- Neurotransmitters are required to carry a "message" from a nerve to a target cell.
- Neurotransmitters only have a small distances to cover to reach their target cells.
- Neurotransmitters bind to receptors within target cells.
A: Neurotransmitters bind to receptors within target cells.

Q: Which of the following descriptions best fits an agonist?
- A compound that has the same effect on a receptor as the endogenous chemical messenger.
- A compound that binds to a receptor and activates it, but to a lesser extent than the endogenous chemical messenger.
- A compound that binds to a receptor, fails to activate it and prevents the endogenous chemical messenger from binding.
- A compound that binds to a receptor, fails to activate it and leads to a drop in inherent biological activity.
A: A compound that has the same effect on a receptor as the endogenous chemical messenger.

Q: Which of the following descriptions best fits an inverse agonist?
- A compound that has the same effect on a receptor as the endogenous chemical messenger.
- A compound that binds to a receptor and activates it, but to a lesser extent than the endogenous chemical messenger.
- A compound that binds to a receptor, fails to activate it and prevents the endogenous chemical messenger from binding.
- A compound that binds to a receptor, fails to activate it and leads to a drop in inherent biological activity.
A: A compound that binds to a receptor, fails to activate it and leads to a drop in inherent biological activity.

Q: Which of the following descriptions best fits an antagonist?
- A compound that has the same effect on a receptor as the endogenous chemical messenger.
- A compound that binds to a receptor and activates it, but to a lesser extent than the endogenous chemical messenger.
- A compound that binds to a receptor, fails to activate it and prevents the endogenous chemical messenger from binding.
- A compound that binds to a receptor, fails to activate it and leads to a drop in inherent biological activity.
A: A compound that binds to a receptor, fails to activate it and prevents the endogenous chemical messenger from binding.

Q: Which of the following terms best describes the study of which functional groups are important in binding a drug to its binding target binding site and which functional groups are not important?
- Pharmacokinetics
- Structure-based drug design
- Pharmacodynamics
- Structure-activity relationships
A: Structure-activity relationships

Q: Which of the following descriptions most accurately describes binding sites and binding regions?
- A binding site is part of a binding region.
- A binding region is part of a binding site.
- A binding region is the same as a binding site.
- A binding region is on a drug whereas a binding site is on a macromolecular target.
A: A binding region is part of a binding site.

Q: Which of the following is not a necessary requirement when designing an agonist?
- The presence of the correct binding groups.
- The correct size and shape of the molecule.
- The correct relative orientation of the binding groups.
- The identical functional groups present in the endogenous chemical messenger.
A: The identical functional groups present in the endogenous chemical messenger.

Q: What sort of agent binds to a receptor using a different binding site from that used by the endogenous chemical messenger, and distorts the binding site such that the endogenous chemical messenger cannot bind?
- An agonist.
- An allosteric antagonist.
- An antagonist acting by the "umbrella" effect.
- An inverse agonist.
A: An allosteric antagonist.

Q: What sort of agent binds to a binding site that is next to the binding site for an endogenous chemical messenger, and sterically blocks the messenger from binding?
- An agonist.
- An allosteric antagonist.
- An antagonist acting by the "umbrella" effect.
- An inverse agonist.
A: An antagonist acting by the "umbrella" effect.

Q: Which of the following best applies to the following: a situation where increasing doses of a drug are required to have the same biological effect?
- Sensitisation
- Tolerance
- Dependence
- Acceptance
A: Tolerance

Q: Which of the following best applies to the following: a situation where cessation of a drug results in withdrawal symptoms?
- Sensitisation
- Tolerance
- Dependence
- Acceptance
A: Dependence

Q: Which of the following situations is feasible as an explanation for tolerance and dependence?
- An increased production of receptors to counteract the presence of an antagonist.
- An increased production of receptors to counteract the presence of an agonist.
- A decreased production of receptors to counteract the presence of an agonist.
- An decreased production of receptors to counteract the presence of an antagonist.
A: An increased production of receptors to counteract the presence of an antagonist.

Q: Which of the following statements is false?
- Drug targets are normally macromolecules.
- Drugs are generally smaller than drug targets.
- Drugs are generally organic molecules.
- Drugs usually act by forming covalent bonds with drug targets.
A: Drugs usually act by forming covalent bonds with drug targets.
Feedback: Some drugs do form covalent bonds to their targets, but most drugs interact by intermolecular binding interactions. The other statements are true. Most drug targets are large molecules (macromolecules) that are far bigger than the drugs that interact with them. There are some inorganic compounds used in medicine, but the vast majority of drugs are organic molecules.

Q: Consider the molecule in blue bound to a binding site and identify the binding interactions (i-iv) that are formed by the various parts of the molecule to the binding site.

[Image]
- iv | Hydrogen bond donor
- iii | Hydrogen bond acceptor
- ii | Ionic bond
- i | Van der Waals interactions
Feedback: Van der Waals interactions take place between regions of molecules consisting solely of carbon and hydrogen atoms. Ionic bonds occur between charges of opposite sign. Hydrogen bonds occur between a molecule acting as a hydrogen bond donor (RXH; where X is normally oxygen or nitrogen), and a molecule acting as hydrogen bond acceptor where a heteroatom is present (normally oxygen or nitrogen). Page reference: 5-9

Q: Identify the binding interactions that might be possible at the specified positions of the following drug:

[Image]
- iv | Ionic interactions
- iii | Hydrogen bond acceptor
- ii | Van der Waals interactions
- i | Hydrogen bond donor
Feedback: Van der Waals interactions take place between molecular regions consisting solely of carbon and hydrogen atoms; for example alkyl groups or aromatic rings. Ionic bonds occur between charges of opposite sign. Hydrogen bonds occur between a molecule acting as hydrogen bond donor (RXH; where X is normally oxygen or nitrogen), and a molecule acting as hydrogen bond acceptor where a heteroatom is present (normally oxygen or nitrogen).

Q: Match the following terms to the descriptions.
- A region of the drug target which can bind to a specific functional group present on a drug. | Binding region
- Functional groups on a drug which are used to bind it to the drug target. | Binding groups
- A hollow or cleft present on the surface of a macromolecule to which a drug can bind. | Binding site
Feedback: The binding site is normally a hollow or cleft on the macromolecular target into which a drug can bind. Specific binding regions within that site 'recognise' specific binding groups on drugs (or ligands) to allow binding interactions to take place. Page reference: 4-5

Q: What are the relative strengths of different types of bonds?
- Covalent > H-bond > Ionic > Van der Waals.
- Van der Waals > Ionic > H-bond > Covalent.
- Covalent > Ionic > H-bond > Van der Waals.
- Ionic > Covalent > Van der Waals > H-bond.
A: Covalent > Ionic > H-bond > Van der Waals.
Feedback: Covalent bonds are strongest since they involve the sharing of electrons between two atoms. Ionic interactions are electrostatic in nature and involve interactions between opposite charges. Hydrogen bonding can be seen as a weak form of ionic interaction. Van der Waals interactions are weakest since they involve attractions between transient regions of charge.

Q: Which of the following statements about protein tertiary structure is false?
- Proteins fold up into a tertiary structure such that most amino acids with hydrophobic residues are exposed to the aqueous surroundings.
- Proteins fold up into a tertiary structure such that most amino acids with hydrophilic residues are exposed to the aqueous surroundings.
- Proteins fold up into a tertiary structure such that most amino acids with hydrophobic residues are in the centre and hidden from the aqueous surroundings.
- Interactions between amino acid residues are important in protein tertiary structure.
A: Proteins fold up into a tertiary structure such that most amino acids with hydrophobic residues are exposed to the aqueous surroundings.
Feedback: In general, proteins fold up such that as many hydrophobic residues as possible are positioned in the centre of the protein such that they interact with each other rather than with water. Hydrophilic amino acids can interact favourably with water and are more likely to be on the outside. Several amino acid side chains interact with each other by means of ionic and hydrogen bonding.

Q: Which of the following descriptions best describes the secondary structure of proteins?
- The arrangement of different protein subunits in a multiprotein complex.
- The order in which amino acids are linked together in a protein.
- The overall three dimensional shape of a protein.
- Regions of ordered structure within a protein.
A: Regions of ordered structure within a protein.
Feedback: Primary structure refers to the order of the amino acids in a protein. Secondary structure indicates regions of ordered structure, and tertiary structure is the overall structure of the protein. Quaternary structure refers to the structure of a multi-protein complex.

Q: Which of the following functional groups is most likely to participate in a dipole-dipole interaction?

[Image]
- Carbonyl or ketone.
- Alkene.
- Aromatic ring.
- Hydroxy or alcohol.
A: Carbonyl or ketone.
Feedback: The ketone will have the strongest dipole moment due to the electronegative oxygen polarising the carbonyl bond. The alcohol will also have a significant dipole moment, but less than that of the ketone. The alkene and aromatic rings may have small or negligible dipole moments depending on their substituents. Page reference: 9

Q: Identify the strongest form of intermolecular bonding that could be formed involving the residue of the amino acid phenylalanine.

[Image]
- Ionic bond.
- Hydrogen bond.
- Van der Waals interactions.
- Dipole-dipole interactions.
A: Van der Waals interactions.

Q: What type of drug name is (3S,4R)-3-Ethyl-4-((1-methyl-1H-imidazol-5-yl)methyl)dihydrofuran-2(3H)-one (used to treat glaucoma)?
- Systematic (IUPAC)
- Research code
- Generic
- Proprietary
A: Systematic (IUPAC) / Proprietary

Q: What term is used to describe the process by which an activate membrane-bound receptor passes a message into the cell to produce a change in cell chemistry?
- Signal transduction
- Signal translocation
- Signal translation
- Signal transcription
A: Signal transduction

Q: What type of drug name is Ventolin (used for asthma)?
- Systematic (IUPAC)
- Research code
- Generic
- Proprietary
A: Proprietary

Q: Penicillins are an example of a group of compounds defined by which of the following classifications?
- By chemical structure
- By pharmacological effect
- By target system
- By site of action
A: By chemical structure

Q: Which of the following can sometimes be used as a drug?
- Hormone
- Carrier protein
- Structural protein
- Tubulin
A: Hormone

Q: Which of the intermolecular bonding interactions below are possible for an alcohol?
- Hydrogen bonding only.
- van der Waals interactions only.
- Ionic bonding only.
- Both hydrogen and ionic bonding.
A: Hydrogen bonding only.

Q: Select a functional group which could be used to study the structure-activty relationships (SAR) of each of the following:
- Drug containing an amine | Amide
- Drug containing an amide | Alkene
- Drug containing an alkene | Alkane
- Drug containing a caboxylic acid | Ester
Also offered: Aromatic ring; Heterocylic ring

Q: Identify the key binding interaction that might be possible at the specified positions (i-iv) of the following drug:

[Image]
- iv | Ionic interactions
- iii | Hydrogen bond acceptor
- ii | Van der Waals interactions
- i | Hydrogen bond donor
Also offered: Dipole interactions; Covalent interactions
Feedback: Van der Waals interactions take place between molecular regions consisting solely of carbon and hydrogen atoms; for example alkyl groups or aromatic rings. Ionic bonds occur between charges of opposite sign. Hydrogen bonds occur between a molecule acting as hydrogen bond donor (RXH; where X is normally oxygen or nitrogen), and a molecule acting as hydrogen bond acceptor where a heteroatom is present (normally oxygen or nitrogen).

Q: How could each of the following reagents be useful in the study of structure-activity relationships (SAR)?
- LiAlH_4 | Reducing a ketone
- CH_3I | Converting an alcohol to an ether
- CH_3OH and H^+ | Converting an acid to an ester
- H_2 and Pd catalyst | Converting an alkene to an alkane
Also offered: Converting an aromatic ring to a cyclohexyl ring; Converting an alcohol to an ester

Q: Which of the following statements is incorrect regarding carrier (also known as transport) proteins?
- They are present in cell membranes.
- They serve to carry non polar molecules across the cell membrane.
- They are required to transport amino acids across cell membranes.
- They are not required to transport steroids across cell membranes.
A: They serve to carry non polar molecules across the cell membrane.
Feedback: Transport proteins carry polar molecules across the cell membrane. Non-polar molecules can dissolve through the hydrophobic cell membrane. Page reference: 27-28

Q: What type of name is LY294002 (a protein kinase inhibitor)?
- Research code
- Proprietary
- Generic
- Systematic (IUPAC)
A: Research code

Q: Which of the following terms best describes the study of which functional groups are important in binding a drug to its target and which functional groups are not important?
- Lock and key theory
- Structure-based drug design
- Koshland's theory of Induced fit
- Structure-activity relationships
A: Structure-activity relationships

Q: Which of the following statements is false?
- A binding site is a part of a macromolecule that acts as a drug target.
- A binding site contains binding regions.
- A binding site is a hydrophilic hollow or cleft on the receptor surface.
- A binding site accepts and binds a chemical messenger.
A: A binding site is a hydrophilic hollow or cleft on the receptor surface.

Q: Which of the following statements is false?
- Drug targets are generally macromolecules.
- Drugs are generally smaller than drug targets.
- Drugs are generally organic molecules.
- Drugs generally act by forming covalent bonds with drug targets.
A: Drugs generally act by forming covalent bonds with drug targets.
Feedback: Some drugs do form covalent bonds to their targets, but most drugs interact by intermolecular binding interactions. The other statements are true. Most drug targets are large molecules (macromolecules) that are far bigger than the drugs that interact with them. There are some inorganic compounds used in medicine, but the vast majority of drugs are organic molecules.

Q: What type of drug name is (3S,4R)-3-ethyl-4-((1-methyl-1H-imidazol-5-yl)methyl)dihydrofuran-2(3H)-one (used for the treatment of glaucoma)?
- Systematic (IUPAC)
- Research code
- Generic
- Proprietary
A: Systematic (IUPAC) / Proprietary

Q: Identify the most likely type of intermolecular bonding that could be formed between a drug and the residue (side chain not the terminal amino or carboxylic acid groups) of the amino acid phenylalanine.

[Image]
- Ionic bond
- Hydrogen bond
- Van der Waals interactions
- Dipole-dipole interactions
A: Van der Waals interactions

Q: Which of the following binding interactions is likely to be the most important initial interaction when a drug first enters a binding site?
- van der Waals interactions
- Covalent bonding
- Hydrogen bonding
- Ionic bonding
A: Ionic bonding

Q: Which of the following is not a necessary requirement when designing an agonist?
- The presence of the correct binding groups.
- The correct size and shape of the molecule.
- The correct relative orientation of the binding groups.
- The identical functional groups to the endogenous chemical messenger.
A: The identical functional groups to the endogenous chemical messenger.

Q: Which of the following statements about protein tertiary structure is false?
- Proteins fold up into a tertiary structure such that most amino acids with hydrophobic residues (side chains) are exposed to the aqueous surroundings.
- Proteins fold up into a tertiary structure such that most amino acids with hydrophilic residues (side chains) are exposed to the aqueous surroundings.
- Proteins fold up into a tertiary structure such that most amino acids with hydrophobic residues (side chains) are in the centre and hidden from the aqueous surroundings.
- Interactions between amino acid residues (side chains) are important in protein tertiary structure.
A: Proteins fold up into a tertiary structure such that most amino acids with hydrophobic residues (side chains) are exposed to the aqueous surroundings.
Feedback: In general, proteins fold up such that as many hydrophobic residues as possible are positioned in the centre of the protein such that they interact with each other rather than with water. Hydrophilic amino acids can interact favourably with water and are more likely to be on the outside. Several amino acid side chains interact with each other by means of ionic and hydrogen bonding.

Q: Which of the following best applies to the following: a situation where increasing doses of a drug are required to have the same biological effect?
- Sensitisation
- Tolerance
- Dependence
- Desensitisation
A: Tolerance

Q: What are the relative strengths of different types of bonds?
- Ionic > Covalent > Hydrogen bond > van der Waals
- Ionic > Covalent > van der Waals > Hydrogen bond
- Covalent > Ionic > Hydrogen bond > van der Waals
- Covalent > Ionic > van der Waals > Hydrogen bond
- Hydrogen bond > van der Waals > Ionic > Covalent
- van der Waals > Hydrogen bond > Covalent > Ionic
A: Covalent > Ionic > Hydrogen bond > van der Waals
Feedback: Covalent bonds are strongest since they involve the sharing of electrons between two atoms. Ionic interactions are electrostatic in nature and involve interactions between opposite charges. Hydrogen bonding can be seen as a weak form of ionic interaction. Van der Waals interactions are weakest since they involve attractions between transient regions of charge.

Q: Consider the molecule in blue bound to a binding site and identify the key binding interaction (i-iv) that may be formed by the various parts of the molecule to the binding site.

[Image]
- iv | Hydrogen bond donor
- iii | Hydrogen bond acceptor
- ii | Ionic bond
- i | Van der Waals interactions
Also offered: Covalent interactions; Dipole interactions
Feedback: Van der Waals interactions take place between regions of molecules consisting solely of carbon and hydrogen atoms. Ionic bonds occur between charges of opposite sign. Hydrogen bonds occur between a molecule acting as a hydrogen bond donor (RXH; where X is normally oxygen or nitrogen), and a molecule acting as hydrogen bond acceptor where a heteroatom is present (normally oxygen or nitrogen). Page reference: 5-9

Q: What term is used to describe the process by which an activated membrane-bound receptor passes a message into the cell?
- Signal transduction
- Signal translocation
- Signal translation
- Signal transcription
A: Signal transduction

Q: Which of the following processes is least likely to occur when a membrane-bound receptor binds its chemical messenger?
- The transport of a chemical messenger into the cell.
- The opening or closing of an ion channel.
- The activation of a signalling protein.
- The activation of a membrane-bound enzyme.
A: The transport of a chemical messenger into the cell.

Q: Which of the following statements best describes induced fit?
- The process by which a binding site alters shape such that it is ready to accept a chemical messenger.
- The process by which a chemical messenger adopts the correct binding conformation before entering a binding site.
- The process by which binding of a chemical messenger to a binding site alters the shape of the binding site.
- The process by which a chemical messenger fits exactly into a binding site like a lock and key.
A: The process by which binding of a chemical messenger to a binding site alters the shape of the binding site.

Q: What type of plots can be used to determine whether an enzyme inhibitor is competitive or non-competitive?
- Michaelis-Menten plots
- Inhibition plots
- Displacement plots.
- Lineweaver-Burk plots
A: Lineweaver-Burk plots

Q: What term is used for enzymes which vary in structure and location but which catalyse the same reaction?
- Isosteres
- Isozymes
- Isotopes
- Isomers
A: Isozymes

Q: Which of the following amino acids acts as an acid-base catalyst in enzyme-catalysed reaction mechanisms?
- Serine
- Phenylalanine
- Histidine
- Tryptophan
A: Histidine

Q: Which of the following amino acids commonly acts as a nucleophilic group in enzyme-catalysed reaction mechanisms?
- Serine
- Phenylalanine
- Histidine
- Valine
A: Serine

Q: Consider the following enzyme-catalysed reaction. What sort of enzyme is involved?

[Image: Queston6EnzymeReaction]
- Esterase
- Phosphorylase
- Decarboxylase
- Protease
A: Phosphorylase

Q: Which of the following descriptions best describes a cofactor?
- A non-protein substance that is required by an enzyme if it is to catalyse a reaction.
- A non-protein organic molecule that is required by some enzymes in order to catalyse a reaction on a substrate.
- A non-protein organic molecule that is bound covalently to the active site of an enzyme, and which is required if the enzyme is to catalyse a reaction on a substrate.
- A compound which is bound to the active site and undergoes a reaction.
A: A non-protein substance that is required by an enzyme if it is to catalyse a reaction.

Q: Which of the following descriptions best describes a substrate?
- A non-protein substance that is required by an enzyme if it is to catalyse a reaction.
- A non-protein organic molecule that is required by some enzymes in order to catalyse a reaction on a substrate.
- A non-protein organic molecule that is bound covalently to the active site of an enzyme, and which is required if the enzyme is to catalyse a reaction on a substrate.
- A compound which is bound to the active site and undergoes a reaction.
A: A compound which is bound to the active site and undergoes a reaction.

Q: Some enzymes have a binding site which is not recognised by the normal substrate, and affects the activity of the enzyme if it is occupied by a ligand. What term is used for such a binding site?
- Active site
- Allosteric binding site
- Secondary binding site
- Inhibitory binding site
A: Allosteric binding site

Q: Which of the following statements is true with respect to the Michaelis constant?
- . It is equal to the concentration of substrate at which the reaction rate is half of its maximum value.
- It is equal to the concentration of inhibitor at which the reaction rate is half of its maximum value.
- It is equal to the concentration of substrate at which the reaction rate is at its maximum value.
- It is equal to the concentration of inhibitor at which the reaction rate is zero.
A: . It is equal to the concentration of substrate at which the reaction rate is half of its maximum value.

Q: Which of the following is NOT true of suicide substrates?
- They are activated by the enzyme-catalysed reaction mechanism.
- They react reversibly with the enzyme
- They form a covalent bond with the active site once activated.
- They are so called because they cause the target enzyme to commit suicide by reacting with them.
A: They react reversibly with the enzyme

Q: Which statement best describes the relevance of an allosteric binding site to medicinal chemistry?
- It is more hydrophobic than normal binding sites and accepts hydrophobic drugs in preference to hydrophilic drugs.
- A larger variety of drug structures will bind to the allosteric site than to the active site.
- Drugs can be designed based on the structure of the endogenous chemicals which bind to allosteric sites and control enzyme activity.
- Drugs can be designed based on the transition state of the enzyme-catalysed reaction.
A: Drugs can be designed based on the structure of the endogenous chemicals which bind to allosteric sites and control enzyme activity.

Q: Which of the following descriptions best describes an allosteric inhibitor?
- A drug that binds to an active site and undergoes a reaction.
- A drug that binds to an active site and inhibits the enzyme, but which is displaced by increasing the concentration of substrate.
- A drug that binds to an active site and inhibits the enzyme, but which is not displaced by increasing the concentration of substrate.
- A drug that binds to a different binding site from the active site and affects the activity of the enzyme.
A: A drug that binds to a different binding site from the active site and affects the activity of the enzyme.

Q: Which of the following descriptions best describes a competitive (reversible) enzyme inhibitor?
- A drug that binds to an active site and undergoes a reaction.
- A drug that binds to an active site and inhibits the enzyme, but which is displaced by increasing the concentration of substrate.
- A drug that binds to an active site and inhibits the enzyme, but which is not displaced by increasing the concentration of substrate.
- A drug that binds to a different binding site from the active site and affects the activity of the enzyme.
A: A drug that binds to an active site and inhibits the enzyme, but which is displaced by increasing the concentration of substrate.

Q: What term is used to describe the binding site of an enzyme where a reaction is catalysed?
- Active site
- Allosteric binding site
- Secondary binding site
- Inhibitory binding site
A: Active site

Q: How many peptides can be formed from the following amino acids:  glycine, leucine, alanine and valine?
- 4
- 48
- 36
- 24
A: 24

Q: What does a medicinal chemistry usually mean by the term "drug"?
- A substance which has a marked effect on the body in order to prevent or treat disease.
- A substance taken by mouth in order to treat or prevent disease.
- An substance which is used illegally for recreation purposes.
- A substance which results in addiction and withdrawal.
A: A substance which has a marked effect on the body in order to prevent or treat disease.

Q: Which of the following descriptions best fits an inverse agonist?
- A compound that has the same effect on a receptor as the endogenous chemical messenger.
- A compound that binds to a receptor and activates it, but to a lesser extent than the endogenous chemical messenger.
- A compound that binds to a receptor, fails to activate it and prevents the endogenous chemical messenger from binding.
- A compound that binds to a receptor, fails to activate it and leads to a drop in inherent biological activity.
A: A compound that binds to a receptor, fails to activate it and leads to a drop in inherent biological activity.
Feedback: An inverse agonist binds to a receptor and stabilises the inactive form of the protein such that the endogenous messenger cannot bind. Any inherent activity associated with the receptor is also lost.

Q: Which of the following best applies to the following: a situation where cessation of a drug results in unpleasant symptoms?
- Sensitisation
- Tolerance
- Dependence
- Desensitisation
A: Dependence
Feedback: If the drug is suddenly stopped, then all the receptors become available. There is too many receptors that makes the cells supersensitive to chemical messengers. This can cause unpleasant biological effects until the normal level of receptors return. During this period, the patient may be tempted to take the drug again and will have then acquired a dependence on the drug.

Q: Which of the following situations is feasible as an explanation for sensitisation?
- An increased production of receptors to counteract the presence of an antagonist.
- An increased production of receptors to counteract the presence of an agonist.
- A decreased production of receptors to counteract the presence of an agonist.
- A decreased production of receptors to counteract the presence of an antagonist.
A: An increased production of receptors to counteract the presence of an antagonist.
Feedback: Cell may compensate for prolonged exposure of antagonist by increasing number of receptors.

Q: Which of the following statements about receptors is false?
- Most receptors are proteins situated inside the cell.
- Receptors contain a hollow or cleft on their surface which is known as a binding site.
- Receptors bind chemical messengers such as neurotransmitters or hormones.
- Receptors do not catalyse reactions on chemical messengers.
A: Most receptors are proteins situated inside the cell.
Feedback: Receptors are usually embedded in cell membrane with some part outside the cell.

Q: Which of the following functional groups is most likely to participate in a dipole-dipole interaction?

[Image]
- Carbonyl or ketone
- Alkene
- Aromatic ring
- Hydroxy or alcohol
A: Carbonyl or ketone
Feedback: The ketone will have the strongest dipole moment due to the electronegative oxygen polarising the carbonyl bond. The alcohol will also have a significant dipole moment, but less than that of the ketone. The alkene and aromatic rings may have small or negligible dipole moments depending on their substituents.

Q: Which of the following statements regarding the binding site of a receptor is false?
- The binding site is normally a hollow or cleft in the surface of a receptor.
- The binding site is normally hydrophillic in nature.
- Chemical messengers fit into binding sites and bind to functional groups within the binding site.
- The binding site contains amino acids which are important to the binding process.
A: The binding site is normally hydrophillic in nature.
Feedback: The binding site on the receptor is usually hydrophobic hollow or cleft on the surface.
  Hint: Ch4

Q: Which of the following statements is false?
- Desolvation is an energy expensive process which involves the removal of water from polar functional groups prior to a drug binding to its binding site.
- Water molecules surrounding a hydrophobic region of a drug form an ordered layer of molecules with high entropy.
- Interaction between the nonpolar regions of a drug and the nonpolar regions of a target require the removal of an ordered water coat and represents a gain in binding energy due to increased entropy.
- Polar functional groups of drugs and targets are solvated by water in an aqueous environment.
A: Water molecules surrounding a hydrophobic region of a drug form an ordered layer of molecules with high entropy.
Feedback: Water molecules surrounding a hydrophobic region of a drug form an ordered layer of molecules with low entropy. Hydrophobic binding releases water and increases entropy, slightly improving binding.

Q: What type of drug name is Ventolin^TM (used for the treatment of asthma)?
- Systematic (IUPAC)
- Research code
- Generic
- Proprietary
A: Proprietary

Q: Why could a structural change to a drug result in a change in the way it binds to the target?
- This is due to the drug being a different shape, which is a steric effect.
- This is due to the drug having a different electron density for binding with the target, which is an electronic effect.
- This is due to the drug having both a different electron density and shape to induce both an electronic and steric effect.
- This is due to either the drug having a different electron density (an electronic effect) or a different shape (a steric effect) or both effects (electronic and steric) at the same time.
A: This is due to the drug being a different shape, which is a steric effect. / This is due to either the drug having a different electron density (an electronic effect) or a different shape (a steric effect) or both effects (electronic and steric) at the same time.

Q: Which of the following statements about neurotransmitters is false?
- Neurotransmitters are released by nerves.
- Neurotransmitters are required to carry a "message" from a nerve to a target cell.
- Neurotransmitters only have a small distances to cover to reach their target cells.
- Neurotransmitters only bind to receptors inside target cells.
A: Neurotransmitters only bind to receptors inside target cells.

Q: Match the following drug names with the drug name types:
- N-(4-hydroxyphenyl)ethanamide | Systematic (IUPAC)
- Paracetamol | Generic
- Panadol^TM | Proprietary
Also offered: Research code

Q: Match the following terms to the descriptions.
- An area of the drug target which can bind to a specific functional group present on a drug. | Binding region
- Functional group on a drug which allows it to bind to the drug target. | Binding group
- A hollow or cleft present on the surface of a macromolecule to which a drug can bind. | Binding site
Also offered: Binding area
Feedback: The binding site is normally a hollow or cleft on the macromolecular target into which a drug can bind. Specific binding regions within that site 'recognise' specific binding groups on drugs (or ligands) to allow binding interactions to take place.

Q: Which of the intermolecular bonding interactions below are possible for an alkene?
- Hydrogen bonding only.
- Van der Waals interactions only.
- Ionic bonding only.
- Both hydrogen and ionic bonding.
A: Van der Waals interactions only.
Feedback: The alkene group has no heteroatoms and can form neither hydrogen bonds nor ionic bonds. Van der Waals interactions are possible.