## TITLE('Melting Temperature (Tm) of DNA')
## DESCRIPTION
## Select the statement that is TRUE or FALSE about melting temperature (Tm) of DNA.
## ENDDESCRIPTION
## KEYWORDS('melting temperature (Tm) of DNA','true/false','multiple choice')
## DBsubject('Molecular 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 = (
[
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the cytosine (C) + guanine (G) base pairing content increases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the cytosine (C) + guanine (G) base pairing content decreases.',
],
[
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the adenine (A) + thymine (T) base pairing content decreases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the adenine (A) + thymine (T) base pairing content increases.',
],
[
'The melting temperature (Tm) of a DNA strand is the temperature
at which half of strands are single-stranded and the other half are double-stranded.',
],
);
@false_groups = (
[
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the cytosine (C) + guanine (G) base pairing content decreases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the cytosine (C) + guanine (G) base pairing content increases.',
],
[
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the adenine (A) + thymine (T) base pairing content increases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the adenine (A) + thymine (T) base pairing content decreases.',
],
[
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the amount of purine nucleobases, adenine (A) + guanine (G), decreases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the amount of purine nucleobases, adenine (A) + guanine (G), increases.',
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the amount of purine nucleobases, adenine (A) + guanine (G), increases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the amount of purine nucleobases, adenine (A) + guanine (G), decreases.',
],
[
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the amount of pyrimidine nucleobases, cytosine (C) + thymine (T), decreases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the amount of pyrimidine nucleobases, cytosine (C) + thymine (T), increases.',
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the amount of pyrimidine nucleobases, cytosine (C) + thymine (T), increases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the amount of pyrimidine nucleobases, cytosine (C) + thymine (T), decreases.',
],
[
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the amount of nucleobases with ketone groups, guanine (G) + thymine (T), decreases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the amount of nucleobases with ketone groups, guanine (G) + thymine (T), increases.',
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the amount of nucleobases with ketone groups, guanine (G) + thymine (T), increases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the amount of nucleobases with ketone groups, guanine (G) + thymine (T), decreases.',
],
[
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the amount of nucleobases with amino groups adenine (A) + cytosine (C), decreases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the amount of nucleobases with amino groups, adenine (A) + cytosine (C), increases.',
'The melting temperature (Tm) of a DNA strand goes up (increases)
when the amount of nucleobases with amino groups, adenine (A) + cytosine (C), increases.',
'The melting temperature (Tm) of a DNA strand goes down (decreases)
when the amount of nucleobases with amino groups, adenine (A) + cytosine (C), decreases.',
],
);
#==========================================================
# GLOBAL SETTINGS
#==========================================================
$topic = 'melting temperature (Tm) of DNA';
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 => '',
);
#==========================================================
# PGML
#==========================================================
BEGIN_PGML
[@ $mode eq "TRUE" ? "Which one of the following statements is TRUE about $topic?" : "Which one of the following statements is FALSE about $topic?" @]*
[_]{$rb}
END_PGML
ENDDOCUMENT();