The software will detect the sensor and load data table and graph

BIL
151
Laboratory
Enzymes:

Practicing
the
Protocol

Be
sure
to
bring
a
laptop,
electronic
pad,
or
other
USB-‐equipped
device
for
recording and
storing
data
and
for
taking
notes.

The
catabolysis
of
hydrogen
peroxide
by
catalase
proceeds
as
follows:
catalase
2H202

-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐-‐>

2H20
+
02
One
simple
way
to
determine
how
well
an
enzyme
is
working
is
to
measure
the
rate
of
its reaction.
To
determine
catalase’s
reaction
rate,
one
could
measure
the
amount
of
H202 decomposed
or,
equally
well,
the
amount
of
H20
or
02
produced,
per
unit
time
(i.e.,
the
rate
of
this decomposition).

Since
02
is
a
gas,
we
can
conveniently
calculate
the
rate
of
its
production
with
an oxygen
gas
sensor.

We
haz
them.

Today
your
team
will
practice
the
methods
you
will
use
for
your
own
original
research
project. By
the
end
of
this
session,
you
should
be
able
to
(1)
operate
the
equipment
confidently,
(2)
know how
to
mix
reagents
suitable
for
your
study,
and
(3)
understand
how
to
collect
raw
data.

2.
Hydrogen
peroxide
Hydrogen
peroxide
(H2O2)
is
a
powerful
oxidizing
agent
produced
as
a
toxic
byproduct
of aerobic
metabolism.
Without
rapid
enzymatic
catalysis,
H202
would
quickly
destroy
essential biomolecules
in
a
living
cell,
resulting
in
cell
damage
and
death.

B.

Experimental
Workstation
and
Equipment
Before
you
begin,
check
your
laboratory
workstation
for
cleanliness,
and
to
be
sure
all
the materials
listed
below
are
present
and
in
good
working
order.

If
something
is
not
right,
check with
your
laboratory
instructor
for
replacements.

1.

Your
Lab
Workstation
Check
your
lab
workstation
to
be
sure
all
the
following
equipment
is
present.

To
connect
the
probe
to
your
laptop
computer,
you
will
need
the
Vernier
adaptor
cable.

This
is either
in
the
box
with
your
probe,
or
available
at
the
TA
desk
at
the
front
of
the
lab.

Before
you
leave
lab
today,
be
sure
all
the
items
listed
above
are
neatly
replaced
on
your
tray
and that
all
spills
are
wiped
up.

TEAMS
WHO
LEAVE
LAB
WORKSTATIONS
DIRTY
WILL
BE
DOCKED
FIVE
POINTS.

3.
Setting
up
the
O2
sensor
and
data
logger
software
One
team
member
with
a
laptop
computer
will
kindly
volunteer
it
for
data
collection.

1.

Go
to
http://www.vernier.com/products/software/logger-‐lite/#download
to
download the
software
you
will
need
on
your
laptop
to
complete
this
experiment.

(If
this
lab
chapter
is
in .pdf

format,
you
may
need
to
cut
and
paste
this
URL
into
your
browser.)

1.

Carefully
and
gently,
place
the
O2
gas
sensor
into
the
plastic
reaction
chamber
a
shown
in Figure
1.

Gently
push
the
sensor
down
until
it
stops.
The
sensor
is
designed
to
seal
the chamber
without
unnecessary
force.

2.

Click
“Collect”
on
the
toolbar
at
the
top
of
the
Logger
Lite
window.
The
sensor
will
start measuring,
1x
per
second,
the
O2
concentration
(as
%O2)
of
the
air
in
the
chamber.

Note
that the
current
%O2
is
displayed
in
the
lower
left
corner
of
the
window,
while
the
readings
over time
are
displayed
on
the
data
table
and
graph.

7.

Breathe
several
times
into
the
reaction
chamber.

Try
to
replace
the
air
in
the
chamber
with your
exhaled
breath.

8.

Quickly,
but
still
carefully
and
gently,
place
the
O2
sensor
into
the
chamber
as
in
step
#1
above.

Now
you
are
ready.

Make
us
proud.

5.
To
ensure
that
the
sensor
is
working
correctly,
click
“Collect”
on
the
toolbar.
The
%O2
should
be recorded
once
per
second
in
the
table
to
the
left
and
on
the
graph.
Try
breathing
into
the
dry plastic
respiration
chamber
and
putting
the
sensor
in
the
top.
The
oxygen
readings
should
go down.
Now
click
“Stop.”
You
can
click
“store”
on
the
toolbar
to
save
one
data
run
and
“save”
to save
an
entire
batch.
To
open
a
fresh
data
table
and
graph,
click
“New.”

6.
Before
beginning
the
experiment,
delegate
duties
to
everyone
in
the
team.
Every
person
must know
how
to
do
every
task,
but
it
is
best
to
assign
duties
such
as
monitoring
the
computer, cleaning
glassware,
recording
times,
etc.
to
specific
team
members
to
avoid
human
error.

11.

Back
at
your
station,
draw
20mL
of
your
H2O2
solution
into
a
labeled
syringe.

12.

Prepare
everything
for
an
experimental
reading,
making
sure
your
LoggerLite
software
is ready,
that
everyone
is
in
position
and
ready
to
do
his/her
job.

16.

The
reaction
begins
very
shortly
after
the
introduction
of
hydrogen
peroxide,
so
click “Collect”
in
the
LoggerLite
program
once
you
have
begun
swirling
your
suspension.
Be
very careful
to
keep
the
probe
dry
or
your
readings
will
become
erratic.

If
this
happens,
use one
of
the
ringstand/fan
assemblies
set
up
along
the
back
table
to
dry
your
probe.

Do
not clamp
the
probe
tightly,
to
avoid
damaging
it.

17.
When
the
%O2
readings
begin
to
plateau,
click
“Stop.”
This
will
happen
automatically
after
300 seconds.

21.
Repeat
this
procedure
twice
more
so
that
you
have
practiced
running
a
control
three
times.

If
you
feel
the
need
for
more
practice,
you
may
do
a
few
additional
runs.