MEDI 2130
INTRODUCTION
Biochemistry
• Biochemistry is the application of chemistry to
study biological processes at the cellular and
molecular level.
 Biochemistry is also concerned with the study of
the structure and function of cellular components,
such as proteins, carbohydrates and lipids.
 Biochemistry is both a life science and a chemical
science; it has provided explanations for the causes
of many diseases in humans.
• Biochemistry is the study of molecular
structures and interactions in living
organisms.
• Biochemists seek to understand living
organisms in terms of chemical reactions.
Biochemistry
The objective of this course:
• To learn fundamental techniques used in
biochemistry.
• To learn some biochemical procedures
and experiments commonly used in
biochemistry laboratories.
• To provide a basis for understanding how
biochemical data is obtained, analyzed
and presented.
Attendance and
activity
midterm
10
Reports
10
Quizzes
10
Final
40
30
Safety rules
1. Listen to or read instructions
carefully before attempting to do
anything.
2. Clean up your lab area at the
conclusion of the laboratory period.
Wear lab coat
• After handling chemicals, remove
gloves and always wash your hands
with soap and water.
• Never taste any chemicals (you should
never taste anything in the lab).
Sign for cautions
Please read the warning signs
and symbols placed on the
reagents.
Chemical hazards
1.
2.
3.
Never mix chemicals together unless
you are told to do so
(and then only in the manner specified).
Never pour water into a
concentrated acid.
Acid
should be poured slowly into water.
Check labels on containers twice to make sure you use the right
chemical and of the correct concentration. Dispose of chemicals in
proper receptacle.
• If you need to smell the odor of a chemical, waft
the fumes toward your nose with one hand. Do not
put your nose over the container and inhale the
fumes.
• Before leaving the lab, the workplace,
reagents and equipment should be put in
order.
• Wash the lab glass. Close the gas valves. Turn
off the taps.
Team work
Instruments
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The only type of glassware that may safely be heated is
either Kimax or Pyrex.
When heating a test tube, move it around slowly over the
flame to distribute the heat evenly. Keep burners in the
middle of the lab table, not on the edge. When heating
liquids in test tubes, never point the tube toward yourself or
anyone else.
Never heat the test tube directly at the bottom but tilt the
tube and heat it gently between the bottom of the tube and
the top of the liquid. Use boiling chips when boiling liquids in
a flask or beaker to prevent bumping.
Droppers
cylinder
Balance
Filter paper
Test tube brush
Rack
Clamps
• Centrifuge - separates materials of varying
density.
• Test tube - used as holder of small amount of
solution.
• Thermometer - measures temperature.
• Wire gauze - used to spread heat of a burner
flame.
• burette - measures volume
of solution.
Certainty vs. Uncertainty
The smallest division of this graduated cylinder is 1 mL. These values are
CERTAIN.
Note: There are no graduation lines between 36 and 37 mL. This value must
be ESTIMATED.
• The error in reading the measurement will be ± 0.1 mL or 1/10 of the
smallest division.
• A reading of the volume is: 36.5 ± 0.1 mL
One person may read this as: 36.6 mL
One person may read this as: 36.4 mL
• NOTE: The value of 36 is CERTAIN
The value of .5, .6 or .4 is ESTIMATED OR UNCERTAIN
•
The certainty of a measurement depends on the precision of the
instrument.
Accuracy vs. Precision
• Accuracy
• Accuracy is defined as the degree of conformity to the truth
and expressed as absolute error.
• Absolute error = experimentally measured value – true value
• Precision is defined as the degree of agreement between
replicate experiments and expressed as standard deviation.
• Precision does not mean accuracy, since measurements may
be highly precise but inaccurate due to a faulty instrument or
technique.
chemical reaction
• A chemical reaction :change of a substance into a
new one that has a different chemical.
• signs of chemical reaction:
1-formation of a precipitate
2-color change
3-evolution of gas
4-temperature change
Exothermic reaction :give off energy and generally
cause the surroundings to get hotter
Endothermic reactions: require energy and generally
cause the surrounding to become cooler
Types of biochemical compounds
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Carbohydrates
Amino acids and proteins
Nucleotides and nucleic acids
Lipids
How to make report
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Name of test
Introduction
Aim
Principle
Procedure
Results
Comments