Page |1
Pharm 203A Fall Midterm Questions and
Correct Answers/ Latest Update / Already
Graded
What is a drug?
Ans: - chemical substance with a known structure
- produces a biological effect
What is pharmacology?
Ans: the chemical control of physiology
What are the four types of regulatory proteins? (R, G I C, E, T)
Ans: - Receptors
- Gated ion channel
- Enzymes
- Transporters (pumps_
How do most drugs work?
Ans: - most drugs bind to regulatory proteins
- often bind to same site where the endogenous ligand bind
All rights reserved © 2025/ 2026 |
, Page |2
- when the drug binds to the protein, the function of behaviour
of the protein is altered = cell physiology altered
What is an allosteric effect?
Ans: - The binding of a ligand to one site on a protein molecule
in such a way that the properties of another site on the same
protein are affected
- Positive or Negative allosteric modulators
What is an agonist?
Ans: A ligand which binds to a receptor protein and
ACTIVATED the receptor
What is an antagonist?
Ans: A ligand which binds to a receptor and does NOT
ACTIVATE the receptor but prevent an agonist from binding or
activating the receptor
What is the reversibility and equilibrium of receptor ligand
interactions?
Ans: - most ligands bind reversibly to proteins
- equilibrium between bound & unbound proteins
All rights reserved © 2025/ 2026 |
, Page |3
- ligand associates and dissociates from the protein
What are irreversible ligands?
Ans: - most are enzyme inhibitors
- binding causes permanent inactivation of the protein
What is affinity?
Ans: - strength of binding between a ligand and its particular
protein
- can be expressed as a numerical value (Kd); allows for
comparisons between drugs
What factors affect binding affinity?
Ans: - shape fit
- electrostatic bonds + distance & angle of bonds
- hydrophobic interaction + distance and angle of the
interactions
How does affinity impact the dose of a drug required?
Ans: - some drugs can stay bound for longer allowing for
greater level of response
All rights reserved © 2025/ 2026 |
, Page |4
- only bound drugs have an effect on the proteins behaviour
- high affinity = lower dose required
- low affinity = higher dose required
What is the relationship between drug concentration and target
occupation?
Ans: hyperbolic relationship
- max = all protein sites are occupied
What are off target side effects?
Ans: Side-effects that happen due to binding of an alternative
site rather than the target site (side-effects may be the actual
effects of alternative sites binding)
How do drugs use competition?
Ans: - a drug can bind to a receptor and prevent the binding of
the natural agonist
- there is competition between the natural agonist and the drug
for binding to the receptor
- agonist: overall effect of natural agonist + drug = increase
receptor stimulation
All rights reserved © 2025/ 2026 |
Pharm 203A Fall Midterm Questions and
Correct Answers/ Latest Update / Already
Graded
What is a drug?
Ans: - chemical substance with a known structure
- produces a biological effect
What is pharmacology?
Ans: the chemical control of physiology
What are the four types of regulatory proteins? (R, G I C, E, T)
Ans: - Receptors
- Gated ion channel
- Enzymes
- Transporters (pumps_
How do most drugs work?
Ans: - most drugs bind to regulatory proteins
- often bind to same site where the endogenous ligand bind
All rights reserved © 2025/ 2026 |
, Page |2
- when the drug binds to the protein, the function of behaviour
of the protein is altered = cell physiology altered
What is an allosteric effect?
Ans: - The binding of a ligand to one site on a protein molecule
in such a way that the properties of another site on the same
protein are affected
- Positive or Negative allosteric modulators
What is an agonist?
Ans: A ligand which binds to a receptor protein and
ACTIVATED the receptor
What is an antagonist?
Ans: A ligand which binds to a receptor and does NOT
ACTIVATE the receptor but prevent an agonist from binding or
activating the receptor
What is the reversibility and equilibrium of receptor ligand
interactions?
Ans: - most ligands bind reversibly to proteins
- equilibrium between bound & unbound proteins
All rights reserved © 2025/ 2026 |
, Page |3
- ligand associates and dissociates from the protein
What are irreversible ligands?
Ans: - most are enzyme inhibitors
- binding causes permanent inactivation of the protein
What is affinity?
Ans: - strength of binding between a ligand and its particular
protein
- can be expressed as a numerical value (Kd); allows for
comparisons between drugs
What factors affect binding affinity?
Ans: - shape fit
- electrostatic bonds + distance & angle of bonds
- hydrophobic interaction + distance and angle of the
interactions
How does affinity impact the dose of a drug required?
Ans: - some drugs can stay bound for longer allowing for
greater level of response
All rights reserved © 2025/ 2026 |
, Page |4
- only bound drugs have an effect on the proteins behaviour
- high affinity = lower dose required
- low affinity = higher dose required
What is the relationship between drug concentration and target
occupation?
Ans: hyperbolic relationship
- max = all protein sites are occupied
What are off target side effects?
Ans: Side-effects that happen due to binding of an alternative
site rather than the target site (side-effects may be the actual
effects of alternative sites binding)
How do drugs use competition?
Ans: - a drug can bind to a receptor and prevent the binding of
the natural agonist
- there is competition between the natural agonist and the drug
for binding to the receptor
- agonist: overall effect of natural agonist + drug = increase
receptor stimulation
All rights reserved © 2025/ 2026 |
