BIOL 373 Exam Questions And
Answers With Verified Solutions
What is physiology? CORRECT ANSWERS The science of the function of living system
What is the difference between process and function? CORRECT ANSWERS - process
= "how"
- function = "why"
What is homeostasis with respect to a fluid? CORRECT ANSWERS Maintenance of a
relatively stable internal cellular fluid
Who coined the term "homeostasis?" CORRECT ANSWERS Walter Cannon
What is pathophysiology? CORRECT ANSWERS The study of when systems fail to
compensate
What is local control? Reflex control? What modulates reflex control? CORRECT
ANSWERS - local control = changes near the site of damage
- reflex control = over long distances; managed by the CNS
List some examples of variables monitored by the CNS CORRECT ANSWERS -
osmolarity
-T
- BP
What are the three types of feedback mechanisms? Which is most common? least
common? CORRECT ANSWERS Negative, positive and feedforward. Negative
feedback →negative very common
→positive very rare
What is responsible for most communication - electrical or chemical signals?
CORRECT ANSWERS Chemical
Define target cells WRT sent signals. CORRECT ANSWERS Target cells are those
cells which are able to respond to chemical signals, and contain a receptor for it.
What are forms of long-range cell-cell communication? CORRECT ANSWERS
endocrine (chemical hormone), neural and neuro endocrine (chemicals at axon terminal
secrete into the bloodstream).
Where are ligand receptors located? What do these specific locations yield in terms of
function? CORRECT ANSWERS A *protein* which projects outside of the membrane or
are within the membrane; hydrophobic ligands will diffuse into the cytoplasm;
,hydrophilic via an intracellular receptor (consider the lipo and hydrophobicity WRT
location)
name the three main types of membrane receptors covered in 373. CORRECT
ANSWERS - ion channel
- enzyme-coupled receptor
- GPCR
What are the main types of second messengers? Name a representative member of
each. CORRECT ANSWERS - nucleotides; cAMP
- lipid-derived molecules; IP_3
- ions; Ca²⁺
How can one signal have different effects on different cell types? CORRECT
ANSWERS One ligand may have several different types of receptors
What aspects of kinetics and thermodynamics affect ligand-receptor interactions?
CORRECT ANSWERS K_eq (rel. affinity), saturation
How can cells change their response to signals? CORRECT ANSWERS - ↑ n_receptors
by changing receptor number or sensitivity
- ↓ n_receptors by internalizing the surface protein
*- Δsensitivity by ℗*
What are the effects of Epi on α receptors? β₂ receptors? CORRECT ANSWERS α
constrict, reducing blood flow; β₂ dilate, increasing blood flow
Explain the difference between an agonist and an antagonist. CORRECT ANSWERS
Agonists exhibit the same response as the ligand, whereas antagonists occupy but do
not activate the receptor
Explain the pathogenesis of cholera. What effect does it have on the molecules?
CORRECT ANSWERS - comes from contaminates *water*
- produce a toxin which affects the small intestine, yielding water loss
- disables intrinsic GTPase activity of α subunit
Explain the activity of GPCRs. What NXP does it have when "off?" When on? How does
it inactivate? What subunits are considered active? CORRECT ANSWERS - consists of
a receptor portion, and then an α and βɣ subunits; the βɣ seperate from the α.
- GDP when off
- GTP when on
- inactivates by hydrolysis of the terminal ℗
- βɣ yield activation
, Which subinit does the GTP attach to? Which has GTPase activity? Does the GPCR
attach another ℗, or does it swap GDP to GTP for activation? CORRECT ANSWERS -
GTP on α
- α has GTPase activity
- GDP is exchanged for GTP for activation
What is the time span for Gα GTP hydrolysis? What disease is implicated in failure of
hydrolysis? CORRECT ANSWERS Usually seconds; collera
Explain tonic control. Is it under parasympathetic control? CORRECT ANSWERS
Δn_signals yielding a ∇ of signals
NOT under parasympathetic control; all modulation by Δn
Explain antagonistic control. Is it under parasympathetic control? What is a good
analogy for it? CORRECT ANSWERS - two effectors acting antagonistically
- yes, it's under parasympathetic control
- T_home being modulated by AC and furnace is a good analogy
Outline a sample reflex pathway CORRECT ANSWERS - stimulus
- sensor/receptor
- afferent
- ∫ centre
- efferent
- target/effector
- response
What are the two definitions of receptor? CORRECT ANSWERS - cell
membrane/intracellular receptors
- cells/structures that convert stimuli into electrical signals (e.g. sensory)
Can there be more than one integrating centre per reflex? CORRECT ANSWERS Yes!
Compare the specificity, nature of, speed, duration and intensity-coding for neural vs.
endocrine reflexes CORRECT ANSWERS Specificity:
N - terminal cells
E - most cells in body
Nature of:
N - elec
E - chem
Speed:
N - fast
E - slower
Duration:
N - very short
E - longer
Coding:
Answers With Verified Solutions
What is physiology? CORRECT ANSWERS The science of the function of living system
What is the difference between process and function? CORRECT ANSWERS - process
= "how"
- function = "why"
What is homeostasis with respect to a fluid? CORRECT ANSWERS Maintenance of a
relatively stable internal cellular fluid
Who coined the term "homeostasis?" CORRECT ANSWERS Walter Cannon
What is pathophysiology? CORRECT ANSWERS The study of when systems fail to
compensate
What is local control? Reflex control? What modulates reflex control? CORRECT
ANSWERS - local control = changes near the site of damage
- reflex control = over long distances; managed by the CNS
List some examples of variables monitored by the CNS CORRECT ANSWERS -
osmolarity
-T
- BP
What are the three types of feedback mechanisms? Which is most common? least
common? CORRECT ANSWERS Negative, positive and feedforward. Negative
feedback →negative very common
→positive very rare
What is responsible for most communication - electrical or chemical signals?
CORRECT ANSWERS Chemical
Define target cells WRT sent signals. CORRECT ANSWERS Target cells are those
cells which are able to respond to chemical signals, and contain a receptor for it.
What are forms of long-range cell-cell communication? CORRECT ANSWERS
endocrine (chemical hormone), neural and neuro endocrine (chemicals at axon terminal
secrete into the bloodstream).
Where are ligand receptors located? What do these specific locations yield in terms of
function? CORRECT ANSWERS A *protein* which projects outside of the membrane or
are within the membrane; hydrophobic ligands will diffuse into the cytoplasm;
,hydrophilic via an intracellular receptor (consider the lipo and hydrophobicity WRT
location)
name the three main types of membrane receptors covered in 373. CORRECT
ANSWERS - ion channel
- enzyme-coupled receptor
- GPCR
What are the main types of second messengers? Name a representative member of
each. CORRECT ANSWERS - nucleotides; cAMP
- lipid-derived molecules; IP_3
- ions; Ca²⁺
How can one signal have different effects on different cell types? CORRECT
ANSWERS One ligand may have several different types of receptors
What aspects of kinetics and thermodynamics affect ligand-receptor interactions?
CORRECT ANSWERS K_eq (rel. affinity), saturation
How can cells change their response to signals? CORRECT ANSWERS - ↑ n_receptors
by changing receptor number or sensitivity
- ↓ n_receptors by internalizing the surface protein
*- Δsensitivity by ℗*
What are the effects of Epi on α receptors? β₂ receptors? CORRECT ANSWERS α
constrict, reducing blood flow; β₂ dilate, increasing blood flow
Explain the difference between an agonist and an antagonist. CORRECT ANSWERS
Agonists exhibit the same response as the ligand, whereas antagonists occupy but do
not activate the receptor
Explain the pathogenesis of cholera. What effect does it have on the molecules?
CORRECT ANSWERS - comes from contaminates *water*
- produce a toxin which affects the small intestine, yielding water loss
- disables intrinsic GTPase activity of α subunit
Explain the activity of GPCRs. What NXP does it have when "off?" When on? How does
it inactivate? What subunits are considered active? CORRECT ANSWERS - consists of
a receptor portion, and then an α and βɣ subunits; the βɣ seperate from the α.
- GDP when off
- GTP when on
- inactivates by hydrolysis of the terminal ℗
- βɣ yield activation
, Which subinit does the GTP attach to? Which has GTPase activity? Does the GPCR
attach another ℗, or does it swap GDP to GTP for activation? CORRECT ANSWERS -
GTP on α
- α has GTPase activity
- GDP is exchanged for GTP for activation
What is the time span for Gα GTP hydrolysis? What disease is implicated in failure of
hydrolysis? CORRECT ANSWERS Usually seconds; collera
Explain tonic control. Is it under parasympathetic control? CORRECT ANSWERS
Δn_signals yielding a ∇ of signals
NOT under parasympathetic control; all modulation by Δn
Explain antagonistic control. Is it under parasympathetic control? What is a good
analogy for it? CORRECT ANSWERS - two effectors acting antagonistically
- yes, it's under parasympathetic control
- T_home being modulated by AC and furnace is a good analogy
Outline a sample reflex pathway CORRECT ANSWERS - stimulus
- sensor/receptor
- afferent
- ∫ centre
- efferent
- target/effector
- response
What are the two definitions of receptor? CORRECT ANSWERS - cell
membrane/intracellular receptors
- cells/structures that convert stimuli into electrical signals (e.g. sensory)
Can there be more than one integrating centre per reflex? CORRECT ANSWERS Yes!
Compare the specificity, nature of, speed, duration and intensity-coding for neural vs.
endocrine reflexes CORRECT ANSWERS Specificity:
N - terminal cells
E - most cells in body
Nature of:
N - elec
E - chem
Speed:
N - fast
E - slower
Duration:
N - very short
E - longer
Coding:
