INTRODUCTION

Islamic University_ GazaFaculty of Health Sciences.Medical Technology Department.

Biochemistry

• Biochemistry is the application of chemistry tostudy 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

15

HW 10

Reports 10

Quizzes 25

Final 40

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.

• Flammable liquids should be used on premises without ignited burners or other sources of open flames. They should be stored in tightly sealed vessels.

Chemical hazards 1. Never mix chemicals together unless you are told to

do so (and then only in the manner specified).2. Never pour water into a concentrated acid.

Acid should be poured slowly into water.3. 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

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 Balance

cylinder Filter paper

Clamps

Test tube brush

Rack

• 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. UncertaintyThe 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 mLOne person may read this as: 36.6 mLOne person may read this as: 36.4 mL•NOTE: The value of 36 is CERTAINThe 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.

Solutions

• Solutions are mixture of two or more substances in a single phase. One constituent is usually regarded as the SOLVENT (material that dissolves another substance) and the others as SOLUTES (substance being dissolved).

Solute + Solvent = Solution• One of the most common types of solutions involves a solid

dissolved in a liquid.• There are several factors that affect the rate of

solubility, or how quickly a solute dissolves (dissolution).

FACTORS AFFECTING SOLUBILITY

• Solubility of a substance in a solvent can be affected by one or more of the following factors:

1. Nature of the solute 2. Nature of the solvent 3. Temperature 4. Pressure ( Affects gas solutes only.)

• Nature of the Solute:• Solubility can be affected by the “nature” of the

solute.• Solutes can be polar or non-polar, ionic or

molecular , soluble or insoluble etc.• For a given solvent, these solute properties can

affect the ability of the substance to dissolve.Nature of the Solvent:

Nature of the solvent:• Solvents can be polar or non-polar, ionic or

molecular etc.• For a given solute, these solvent properties can

affect the ability of the solvent to dissolve the solute.

The concentration of a solution

• The concentration of a solution • It represents the amount of solute dissolved in a

unit amount of solvent or of solution, and can be expressed in a variety of ways (qualitatively and quantitatively).

I. Qualitative Expressions of Concentration A solution can be qualitatively described as • Diluted: a solution that contains a small proportion

of solute relative to solvent, or • Concentrated: a solution that contains a large

proportion of solute relative to solvent.

II. Quantitative Expressions of Concentration • Units of mass and volume:• The basic international unit of mass is the

kilogram (kg) and that of volume is the liter (L). Frequently, fractions of these units are used instead. Mass units:

• 1 gram (g) = 10-3 kg • 1 milligram (mg) = 10-3 g• 1 microgram (g) = 10-6 g

• Volume units:• 1 liter (L) = 1 dm3 (cubic decimeter)• 1 deciliter (dL) = 10-1 L = 100 mL• 1 milliliter (mL) = 10-3 L = 1 cm3 (cubic

centimeter)• 1 microliter (L) = 10-6 L = 1 mm3

(cubic millimeter)

• Methods:1) Percentages2) Molar concentrations3) Normality

1) Percentages

PercentagesPercent means parts per 100It is expressed by two ways according to the nature of solvent: A -Percent / volume B. Percent by mass: Indicated % (W/W)

A -Percent / volume It is further divided into 2 types according to the nature of solute:Volume / Volume [Indicated % (v/v)], when the solute is liquid, = Volume of solute/ Volume of solution x 100. Less commonly usedWeight / Volume [Indicated % (w/v)], When the solute is a solid, = Mass of solute (g) / Volume of solution (mL) x 100. More commonly used.

volume/volume

• Rubbing alcohol is generally 70% by volume isopropyl alcohol. That means that 100 ml of solution contains 70 ml of isopropyl alcohol.

• That also means that a liter (or 1000 ml) of this solution has 700 ml of isopropyl alcohol plus enough water to bring it up a total volume of 1 liter, or 1000 ml.

B. Percent by mass: Indicated % (W/W) Mass of solute (g) / Mass of solution (g) x 100%What is the weight percent of glucose in a solution made by

dissolving 4.6 g of glucose in 145.2 g of water?• Analysis:

To get weight percent we need the weight of the solute and the total weight of the solution.

• Determine total weight of solution: 4.6 g+ 145.2 g = 149.8 g

• Calculate percent: • Weight % glucose = 4.6 g glucose x 100 = 3.1% glucose

149.8 g solution

• How much solute is present in 756.1 mL of a 14.7% (mass/volume) HCl solution?

Mass/volume % = (masssolute/volumesolution) 100

14.7 % = (x / 756.1 mL ) 100 x = 0.147 (756.1 mL) x = mass of solute = 111g

• II- Molarity (M):• - Another way of expressing concentration is

called molarity. Molarity is the number of moles of solute dissolved in one liter of solution. The units, therefore are moles per liter, specifically it's moles of solute per liter of solution.

• Molarity = moles of solute liter of solution

• Rather than writing out moles per liter, these units are abbreviated as M or M.

• M = wt X 1000 MW X Vml

• Normality: N = moles of reactive units per liter (equivalents per liter).

• Dilution:

• - Diluted solutions can be prepared from concentrated solutions

• M conc X V conc = M dil X V dil

Types of analysis

1. Qualitative chemistry provides information about the elemental make-up or a composition analysis of a test sample by identifying individual elements or groupings of elements found in the sample. The qualitative test process can be used for material identification and detection of impurities and contaminants in test samples.

Quantitative chemical analysis

2. Quantitative chemical analysis is performed to accurately determine the concentration, amount or percentage of one or more elements in a test sample. •This technique, along with qualitative analysis, provides information on what and how much of each element is present in a sample for a complete elemental analysis.

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 precipitate2-color change3-evolution of gas4-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

• Carbohydrates• Amino acids and proteins• Nucleotides and nucleic acids• Lipids

How to make report

• Name of test• Aim • Principle• Procedure• Results • Comments