## TITLE('Vision and Hearing Transduction')
## DESCRIPTION
## Select the statement that is TRUE or FALSE about vision and hearing transduction.
## ENDDESCRIPTION
## KEYWORDS('vision and hearing transduction','true/false','multiple choice')
## DBsubject('Cell Biology')
## DBchapter('')
## DBsection('')
## Date('2026-07-12')
## Author('Neil R. Voss')
## Institution('Roosevelt University')

DOCUMENT();

loadMacros(
  "PGstandard.pl",
  "PGML.pl",
  "PGchoicemacros.pl",
  "parserRadioButtons.pl",
  "PGcourse.pl",
);

TEXT(beginproblem());
$showPartialCorrectAnswers = 1;

#==========================================================
# AUTO-GENERATED GROUPS FROM YAML
#==========================================================

@true_groups = (
  [
    'Rhodopsin consists of an opsin protein plus a retinal chromophore.',
    'Rhodopsin is formed when opsin binds retinal.',
  ],
  [
    'Light causes retinal isomerization that triggers a conformational change in opsin.',
    'Photon absorption changes retinal shape and activates rhodopsin.',
  ],
  [
    'In rods, activated rhodopsin activates a G protein that leads to phosphodiesterase activation.',
    'Phototransduction uses a G protein cascade that activates phosphodiesterase (PDE).',
  ],
  [
    'In rods, phosphodiesterase (PDE) activity lowers cGMP concentration.',
    'Phototransduction reduces cGMP by increasing its breakdown.',
  ],
  [
    'Lower cGMP closes CNG channels in rod outer segments.',
    'Rod CNG channels close when cGMP levels fall.',
  ],
  [
    'Rod photoreceptors hyperpolarize in response to light.',
    'Light reduces inward current in rods, causing hyperpolarization.',
  ],
  [
    'In darkness, rods have relatively high cGMP and open CNG channels.',
    'Dark current in rods is supported by cGMP gated channel opening.',
  ],
  [
    'Cones support color vision and function best at higher light levels than rods.',
    'Rods are more sensitive to low light than cones.',
  ],
  [
    'Hearing depends on mechanotransduction in hair cells of the inner ear.',
    'Sound is converted into electrical signals by hair cell deflection.',
  ],
  [
    'Tip links connect stereocilia and contribute to opening mechanosensitive transduction channels.',
    'Mechanical tension through tip links can gate hair cell transduction channels.',
  ],
  [
    'Hair cell depolarization can occur when K<sup>+</sup> enters from K<sup>+</sup> rich endolymph.',
    'K<sup>+</sup> influx from endolymph can drive hair cell depolarization.',
  ],
  [
    'Hair cells release neurotransmitter to afferent neurons when depolarized.',
    'Hair cell signaling to the auditory nerve occurs through synaptic transmission.',
  ],
  [
    'Unlike many sensory receptors that depolarize to stimulus, rods hyperpolarize to light.',
    'Rods are unusual because the light response is hyperpolarization, NOT depolarization.',
  ],
);
@false_groups = (
  [
    'Rhodopsin is a receptor tyrosine kinase that phosphorylates retinal.',
    'Rhodopsin is an ion channel that directly conducts photons into the cell.',
  ],
  [
    'In rods, light increases cGMP to open more CNG channels.',
    'Phototransduction begins by synthesizing cGMP from GDP.',
  ],
  [
    'Activated rhodopsin directly converts ATP into cGMP without enzymes.',
    'Phototransduction activates adenylyl cyclase to raise cAMP in rods.',
  ],
  [
    'phosphodiesterase (PDE) increases cGMP concentration by synthesizing it from GTP.',
    'phosphodiesterase (PDE) terminates signals by producing cGMP in the outer segment.',
  ],
  [
    'Rod CNG channels open when cGMP levels fall.',
    'CNG channels close in darkness because cGMP is highest in light.',
  ],
  [
    'Rod photoreceptors depolarize strongly in response to light.',
    'Light opens sodium channels in rods and increases inward current.',
  ],
  [
    'In darkness, rods have low cGMP and all CNG channels are closed.',
    'Dark current is produced by closing CNG channels in rod outer segments.',
  ],
  [
    'Cones are more sensitive to dim light than rods.',
    'Rods are responsible for most color discrimination in bright light.',
  ],
  [
    'Hearing relies mainly on GPCR signaling cascades that take seconds to operate.',
    'Hair cells detect sound by photoreception in the cochlea.',
  ],
  [
    'Tip links prevent ion channels from opening and block mechanotransduction.',
    'Tip links stabilize stereocilia but do NOT help gate mechanotransduction channels.',
  ],
  [
    'Hair cells depolarize mainly because Na<sup>+</sup> enters from endolymph through ENaC channels.',
    'Hair cells depolarize mainly because K<sup>+</sup> leaves the cell into endolymph when stereocilia deflect.',
  ],
  [
    'Hair cells do NOT use synapses and communicate only by gap junctions to the auditory nerve.',
    'Hair cells send action potentials down the cochlea without neurotransmitter release.',
  ],
);

#==========================================================
# GLOBAL SETTINGS
#==========================================================

$topic = 'vision and hearing transduction';
my $local_random = PGrandom->new();
$local_random->srand($problemSeed);
my @mode_choices = ("TRUE", "FALSE");
$mode = $mode_choices[$local_random->random(0, $#mode_choices, 1)];
$num_distractors = 4;
#==========================================================
# SELECT GROUP
#==========================================================

my (@selected_group, @opposite_groups);

if ($mode eq "TRUE") {
  $group_index      = $local_random->random(0, scalar(@true_groups)-1, 1);
  @selected_group   = @{ $true_groups[$group_index] };
  @opposite_groups  = @false_groups;
} else {
  $group_index      = $local_random->random(0, scalar(@false_groups)-1, 1);
  @selected_group   = @{ $false_groups[$group_index] };
  @opposite_groups  = @true_groups;
}

#==========================================================
# PICK CORRECT + DISTRACTORS
#==========================================================

my $correct_index = $local_random->random(0, $#selected_group, 1);
$correct = $selected_group[$correct_index];

my @available_group_indices = (0 .. $#opposite_groups);
my @selected_distractor_indices = ();

while (@selected_distractor_indices < $num_distractors && @available_group_indices > 0) {
  my $random_index = $local_random->random(0, scalar(@available_group_indices)-1, 1);
  push @selected_distractor_indices, splice(@available_group_indices, $random_index, 1);
}

@distractors = ();
foreach my $group_idx (@selected_distractor_indices) {
  my @group = @{ $opposite_groups[$group_idx] };
  my $distractor_index = $local_random->random(0, $#group, 1);
  my $distractor = $group[$distractor_index];
  push @distractors, $distractor;
}

@choices = ($correct, @distractors);

#==========================================================
# SHUFFLE CHOICES (SEED-STABLE)
#==========================================================

my @choice_indices = (0 .. $#choices);
my @choice_shuffled = ();
while (@choice_indices) {
  my $pick = $local_random->random(0, $#choice_indices, 1);
  push @choice_shuffled, splice(@choice_indices, $pick, 1);
}
@choices = @choices[@choice_shuffled];

#==========================================================
# RADIO BUTTONS WITH A/B/C/D/E LABELS
#==========================================================

$rb = RadioButtons(
  [@choices],
  $correct,
  labels        => ['A','B','C','D','E'],
  displayLabels => 1,
  randomize     => 0,
  separator     => '<div style="margin-bottom: 0.7em;"></div>',
);

#==========================================================
# PGML
#==========================================================

BEGIN_PGML

[@ $mode eq "TRUE" ? "Which one of the following statements is <span style='color: #127663;'><strong>TRUE</strong></span> about $topic?" : "Which one of the following statements is <span style='color: #ba372a;'><strong>FALSE</strong></span> about $topic?" @]*

[_]{$rb}

END_PGML

ENDDOCUMENT();