BIO 3P3 EXAM WITH VERIFIED AND
CORRECT ANSWERS.
When will diffusion be the fastest between compartments? - CorreCt
Answers -when there is a large difference in # of molecules between them
(flux is proportional to change in conc)
Demyelinating neuropathy - Guillain Barre (disease of peripheral nerves) -
CorreCt Answers -molecular mimicry between microbial & nerve antigens
lead to immune stimulation that induces aberrant autoimmune response
targeting peripheral nerves & their spinal roots
antibody injures myelin or axonal membrane (remyelination is possible but
axonal regeneration is not)
result: APs conducted at different velocities so loss of synchrony of
conduction in response to stimulus
Measuring conduction velocity - CorreCt Answers -apply shock through
proximal (S2) or distal (S1) stimulating electrode & measure AP
conduction vel. = distance from S1 to S2/(ts2 - ts1)
Duchenne Muscular Dystrophy (DMD) - CorreCt Answers -point mutation
or deletion of gene for dystrophin protein (x-linked recessive)
dystrophin acts as shock absorbed during contraction
,Why is Ca2+ a good 2nd messenger? - CorreCt Answers -small influxes of
Ca2+ lead to rapid & dramatic changes in intracellular [Ca2+]
Plasma membrane Ca2+ transports - CorreCt Answers -PMCA, NCX
exchanger, voltage-gated Ca2+ channels
Mitochondria Ca2+ transports - CorreCt Answers -calcium uniporter
(MCU) - brings Ca2+ into matrix 2Na:1Ca exchanger - releases Ca2+ from
matrix
Ca:2H exchanger
SR Ca2+ transports - CorreCt Answers -Ca2+ channels (for release)
SERCA (for reuptake)
SERCA vs. PMCA - CorreCt Answers -- PMCA on plasma membrane,
SERCA on SR membrane
- PMCA maintains low [Ca2+], SERCA restores low [Ca2+]
- PMCA has 4 genes, SERCA has 3
- both are high affinity but low capacity
Inhibitor of SERCA - CorreCt Answers -phospholambin (PLN) - when
phosphorylated, SERCA is active
"ON" reactions - CorreCt Answers -stimuli induce Ca2+ entry
, "OFF" reactions - CorreCt Answers -Ca2+ is removed from cell or stored in
SR & mitochondria
NCX - CorreCt Answers -- 3Na in, 1 Ca2+ out (small inward current)
- activity depends on Na gradient to drive Ca movement & voltage gradient
- channel can reverse direction when Em > Er
- low affinity, high capacity
MCU - CorreCt Answers -- low affinity, located at hot spots where [Ca] is
high enough
- made up of 4 parts: uniporter + 3 regulators
MICU 1 & 2: mitochondrial Ca uptake proteins
EMRE: essential MCU regulator
at rest, EMRE recruits MICUs to keep MCU closed. Increase in [Ca] causes
Ca2+ to bind to MICU & open MCU
Low affinity mechanisms for transporting bulk amounts of Ca2+ (fast &
urgent) - CorreCt Answers -exchangers, channels & uniporters
high affinity, fine-tuning transport of Ca - CorreCt Answers -ATPases
mitochondrial dysregulation of Ca2+ homeostasis - CorreCt Answers -
forms ROS, stimulates Kreb's cycle which increases e- flow through ETC
and stimulates NOS (NO inhibits ETC complex 1 & 4 causing more ROS)
CORRECT ANSWERS.
When will diffusion be the fastest between compartments? - CorreCt
Answers -when there is a large difference in # of molecules between them
(flux is proportional to change in conc)
Demyelinating neuropathy - Guillain Barre (disease of peripheral nerves) -
CorreCt Answers -molecular mimicry between microbial & nerve antigens
lead to immune stimulation that induces aberrant autoimmune response
targeting peripheral nerves & their spinal roots
antibody injures myelin or axonal membrane (remyelination is possible but
axonal regeneration is not)
result: APs conducted at different velocities so loss of synchrony of
conduction in response to stimulus
Measuring conduction velocity - CorreCt Answers -apply shock through
proximal (S2) or distal (S1) stimulating electrode & measure AP
conduction vel. = distance from S1 to S2/(ts2 - ts1)
Duchenne Muscular Dystrophy (DMD) - CorreCt Answers -point mutation
or deletion of gene for dystrophin protein (x-linked recessive)
dystrophin acts as shock absorbed during contraction
,Why is Ca2+ a good 2nd messenger? - CorreCt Answers -small influxes of
Ca2+ lead to rapid & dramatic changes in intracellular [Ca2+]
Plasma membrane Ca2+ transports - CorreCt Answers -PMCA, NCX
exchanger, voltage-gated Ca2+ channels
Mitochondria Ca2+ transports - CorreCt Answers -calcium uniporter
(MCU) - brings Ca2+ into matrix 2Na:1Ca exchanger - releases Ca2+ from
matrix
Ca:2H exchanger
SR Ca2+ transports - CorreCt Answers -Ca2+ channels (for release)
SERCA (for reuptake)
SERCA vs. PMCA - CorreCt Answers -- PMCA on plasma membrane,
SERCA on SR membrane
- PMCA maintains low [Ca2+], SERCA restores low [Ca2+]
- PMCA has 4 genes, SERCA has 3
- both are high affinity but low capacity
Inhibitor of SERCA - CorreCt Answers -phospholambin (PLN) - when
phosphorylated, SERCA is active
"ON" reactions - CorreCt Answers -stimuli induce Ca2+ entry
, "OFF" reactions - CorreCt Answers -Ca2+ is removed from cell or stored in
SR & mitochondria
NCX - CorreCt Answers -- 3Na in, 1 Ca2+ out (small inward current)
- activity depends on Na gradient to drive Ca movement & voltage gradient
- channel can reverse direction when Em > Er
- low affinity, high capacity
MCU - CorreCt Answers -- low affinity, located at hot spots where [Ca] is
high enough
- made up of 4 parts: uniporter + 3 regulators
MICU 1 & 2: mitochondrial Ca uptake proteins
EMRE: essential MCU regulator
at rest, EMRE recruits MICUs to keep MCU closed. Increase in [Ca] causes
Ca2+ to bind to MICU & open MCU
Low affinity mechanisms for transporting bulk amounts of Ca2+ (fast &
urgent) - CorreCt Answers -exchangers, channels & uniporters
high affinity, fine-tuning transport of Ca - CorreCt Answers -ATPases
mitochondrial dysregulation of Ca2+ homeostasis - CorreCt Answers -
forms ROS, stimulates Kreb's cycle which increases e- flow through ETC
and stimulates NOS (NO inhibits ETC complex 1 & 4 causing more ROS)
