PCB 3023 Exam 4 | UPDATED Questions with 100% Verified Answers
Question:
What is a Ligand?
Answer:
a molecule that binds to receptrors
Question:
What is an agonist?
Answer:
A ligand that binds to a receptor to initiate a response
Question:
What is an antagonist?
Answer:
A ligand that binds to a receptor to prevent a response
Question:
What are intracellular signaling molecules? Provide an
example
Answer:
Seconds messengers.
ie. cAMP
Question:
What are effector proteins? What can they do?
Answer:
The target proteins in a pathway. Can mediate cell responses
Question:
Signals can act over short range OR long range. T/F?
Answer:
True
,Question:
Where are extracellular signaling molecules secreted?
Answer:
Outside of the cell. Example: into the bloodstream
Question:
What is an endocrine cell? Provide an example
Answer:
A cell that produces long range hormones and secretes them into the blood stream to
affect a target cell.
Example: insulin
Question:
What is a paracrine cell? Provide two examples
Answer:
A cell that releases signal molecules that diffuse locally.
Example: Cytokines regulate local inflammation. Growth factors
Question:
What is an autocrine cell? Provide an example
Answer:
A cell that depends on its own signaling molecules
Example: cancer cells
Question:
What are synaptic cells? Provide an example
Answer:
Cells that secrete neurotransmitters from their axons terminal
Question:
What is a synapse?
Answer:
the junction of the nerve cell (neuron). Delivers chemical signal to adjacent neuron
,Question:
What is a contact-dependent cell? Provide an example
Answer:
A cell that does not depend on secreted signaling molecules. The cell must make direct
physical contact through ligand and receptor, both of which are located in plasma
membrane.
Example: Some signaling in embryonic development.
Question:
Some signal molecules (Ligands) can induce different
responses in different target cells by affecting different
receptors OR by resulting in different products T/F?
Answer:
True
Question:
After acetylcholine is secreted from cells, it is long-lived,
because it has to reach target cells all over body. T/F?
Answer:
False. Acetylcholine would be short-lived
Question:
Where are receptors usually located?
Answer:
They can be at the cell surface (plasma membrane) OR, if the ligand is small and
hydrophobic, within the cell.
Question:
Describe the steroid hormone cortisol as a ligand.
Answer:
Cortisol is able to diffuse through the plasma membrane and bind with a nuclear
receptor protein (which later acts a a transcription regulator). It can then move through a
nuclear pore channel and bind to the regulatory region of a targeted gene, leading to
, transcription and translation.
Question:
What response does exposure to extracellular signals in an
intracellular pathway produce? Does this pathway occur fast
or slow?
Answer:
Alteration of free-floating ribosome and protein function. Occurs fast
Question:
What response does exposure to extracellular signals in an
nuclear signaling pathway produce? Does this pathway occur
fast or slow?
Answer:
Alteration of DNA transcription and eventually mRNA and protein synthesis. Occurs
slowly.
Question:
Signaling molecules are amplified and integrated by multiple
factors. T/F?
Answer:
True. Primary transduction typically amplifies the signal.
Question:
What is the key mechanism for molecular on/off switches?
Why?
Answer:
Phosphorylation. Presence of a phosphate may turn a factor on or off. Common because
it is reversible
Question:
What is phosphorylation?
Answer:
Question:
What is a Ligand?
Answer:
a molecule that binds to receptrors
Question:
What is an agonist?
Answer:
A ligand that binds to a receptor to initiate a response
Question:
What is an antagonist?
Answer:
A ligand that binds to a receptor to prevent a response
Question:
What are intracellular signaling molecules? Provide an
example
Answer:
Seconds messengers.
ie. cAMP
Question:
What are effector proteins? What can they do?
Answer:
The target proteins in a pathway. Can mediate cell responses
Question:
Signals can act over short range OR long range. T/F?
Answer:
True
,Question:
Where are extracellular signaling molecules secreted?
Answer:
Outside of the cell. Example: into the bloodstream
Question:
What is an endocrine cell? Provide an example
Answer:
A cell that produces long range hormones and secretes them into the blood stream to
affect a target cell.
Example: insulin
Question:
What is a paracrine cell? Provide two examples
Answer:
A cell that releases signal molecules that diffuse locally.
Example: Cytokines regulate local inflammation. Growth factors
Question:
What is an autocrine cell? Provide an example
Answer:
A cell that depends on its own signaling molecules
Example: cancer cells
Question:
What are synaptic cells? Provide an example
Answer:
Cells that secrete neurotransmitters from their axons terminal
Question:
What is a synapse?
Answer:
the junction of the nerve cell (neuron). Delivers chemical signal to adjacent neuron
,Question:
What is a contact-dependent cell? Provide an example
Answer:
A cell that does not depend on secreted signaling molecules. The cell must make direct
physical contact through ligand and receptor, both of which are located in plasma
membrane.
Example: Some signaling in embryonic development.
Question:
Some signal molecules (Ligands) can induce different
responses in different target cells by affecting different
receptors OR by resulting in different products T/F?
Answer:
True
Question:
After acetylcholine is secreted from cells, it is long-lived,
because it has to reach target cells all over body. T/F?
Answer:
False. Acetylcholine would be short-lived
Question:
Where are receptors usually located?
Answer:
They can be at the cell surface (plasma membrane) OR, if the ligand is small and
hydrophobic, within the cell.
Question:
Describe the steroid hormone cortisol as a ligand.
Answer:
Cortisol is able to diffuse through the plasma membrane and bind with a nuclear
receptor protein (which later acts a a transcription regulator). It can then move through a
nuclear pore channel and bind to the regulatory region of a targeted gene, leading to
, transcription and translation.
Question:
What response does exposure to extracellular signals in an
intracellular pathway produce? Does this pathway occur fast
or slow?
Answer:
Alteration of free-floating ribosome and protein function. Occurs fast
Question:
What response does exposure to extracellular signals in an
nuclear signaling pathway produce? Does this pathway occur
fast or slow?
Answer:
Alteration of DNA transcription and eventually mRNA and protein synthesis. Occurs
slowly.
Question:
Signaling molecules are amplified and integrated by multiple
factors. T/F?
Answer:
True. Primary transduction typically amplifies the signal.
Question:
What is the key mechanism for molecular on/off switches?
Why?
Answer:
Phosphorylation. Presence of a phosphate may turn a factor on or off. Common because
it is reversible
Question:
What is phosphorylation?
Answer:
