Majmaah University
College of Dentistry
BCH 113
Practical
Biochemistry
2
Objectives
 Practical biochemistry course is designed to
teach students the fundamental techniques used
in biochemistry.
 In this course students will be exposed to some
biochemical procedures and experiments
commonly used in biochemistry laboratories.
 To provide a basis for understanding how
biochemical data is obtained, analyzed and
presented.
Introduction of biochemistry test and
their importance
About the course …
Laboratory Procedures
Biosafety Measures
Material Downloading
Spectrophotometry
About the course …
Biochemistry is an extension of the last year
Biochemistry course, but this semester only Lab.
The practical part of the course is clinically oriented
towards the laboratory diagnosis of pathological
conditions
mostly
encountered
in
patient
healthcare.
Laboratory Policies
Attendance
Attendance in the lab is obligatory.
You are allowed to enter the teaching room within the
first 10 min of the lab session.
If you miss a lab session, you will NOT be allowed to
repeat the missed lab experiment under any
circumstances.
Downloads
you are required to download the week’s experiment
and bring the hard copy to the lab, and no excuses will
be accepted if you come to the lab without your own
copy.
The download procedure is similar to that of the earlier
semesters.
Downloads (cont.)
After downloading experimental protocols, you are
required to study the lab exercise before coming to the
lab to avoid any confusion.
At the end of the lab session, a report with completed lab
work will be submitted to the lab instructor.
Material Downloading
Experimental protocols will be available on the
website regularly.
You are required to study the lab exercise before
coming to the lab to avoid any confusion.
At the end of the lab session, a report with
completed lab work will be submitted to the lab
instructor.
Laboratory Procedures
For determination
of glucose, cholesterol,
triglycerides, LDL, HDL, GOT, sodium, calcium,
creatinine, fluoride, alkaline phosphate enzyme and
ascorbic acid, laboratory kits depending on
spectrophotometric techniques will be used.
Laboratory Procedures
For fluid sampling, automatic pipettes with
disposable tips will be used.
Automatic pipettes are precision instruments that
are used to deliver small volumes accurately. They
must be handled with respect and extra care.
Laboratory Procedures
A spectrophotometer will be finally used for
measurement of absorption values of the colored
reaction products.
Biosafety Measures
In the biomedical lab, there are many hazards.
Most accidents can be prevented by following the
rules, being prepared for the lab, and by thinking
about what you are doing.
Always behave with consideration for others’ safety.
Always remember you are handling biological fluids.
Cleanup
You should cleanup your work area after the
lab experiment and return it back the way you
found it.
Both detergent & disinfectant
solutions are available in the lab in
spray bottles, and every student
should bring his own soft tissue
paper.
Waste disposal
There are 2 types of containers
in the lab:
• Green
(for general waste)
• Yellow (for biohazard material)
Safety measures & rules
Always wear your lab coat
before entering the lab.
Use goggles & gloves if
necessary as directed by
your Doctor.
Safety measures & rules
Behave in a respectable and responsible way allover
the lab.
Only take your notebook and pen to the lab area; bags,
coats, …etc should be kept in one place. Foods and Tea
are strictly prohibited in Lab.
Mobile phones are allowed in condition
to be kept on a silent mode.
Safety measures & rules
Do not touch anything from the lab equipment
unless told to do so by the Doctor.
Assume all chemicals in the lab are
dangerous.
Do not taste any solution or chemical.

Safety measures & rules
Do not pipette any solution by mouth.
Do not carry reagents around the lab.
No food or drink is allowed in the lab.
Safety measures & rules
Note the position of the safety showers in the
lab.
Wash your hands thoroughly before leaving the
lab.
Biosafety Measures
Disposable tips, test tubes and
gloves are disposed of in the
biohazard waste.
Clean up your lab bench after you terminate
working and wash your hands with detergent and
disinfectant before you leave the lab.
Spectrophotometry
Spectrophotometric Estimation of
Body Fluids
Principle:
Many important biological solutions are estimated
as coloured solutions, in which the intense of the
colour is proportional to the concentration of the
biological substance.
When light passes in a coloured solution, it has
specific wave length, therefore, the intense of the
colour is measured as its optical density or
absorbance of its wave length.
Spectrophotometric Estimation of
Body Fluids
Spectrophotometer measures the absorbance of
the coloured solutions, and the intense of colours
are read on its scale.
The zero point of the spectrophotometer should
be first adjusted with a solution known as the
blank. A water blank or a reagent blank may be
used. Sometimes the zero point is adjusted
against air, this depends upon the procedure used.
Spectrophotometeric Estimation of
Body Fluids
The sample unknown solution is compared with a
known standard to obtain the exact concentration of
the test unknown sample.
The following formula is usually used:
A sample
Conc.sample
_________
A standard
* Conc.Standard=……mg/dl
Spectrophotometric Estimation
of Body Fluids
A sample:
Absorbance (optical density, reading) of
the sample.
A standard: Absorbance (optical density, reading) of
the standard.
Conc.sample: Concentration of the test unknown
sample.
Conc. Standard: Concentration of the known
standard solution.
Spectrophotometer
A spectrophotometer is a device to measure the
intensity of light after it has passed through an
absorbing medium. In its simplest form it
consists of:
Application
1. Spectrophotometer helps in measuring the
concentration of any unknown substance. If
the substance by itself is coloureless, it can be
chemically converted to a coloured substance.
2. The Spectrophotometer can also be used to
measure the turbidity of solutions (e.g.
bacterial suspension), but the nepheometer is
a better measure of turbidity.