BIOCHEM: LAB

Biological molecules

- Amino acid - Sugars - Nucleotides - Lipids

Biological Macromolecules

- Protein - Carbohydrates - Nucleic Acid

Sucrose solution

- a mixture of sucrose and distilled water

Viruses

- assemblages of a DNA or RNA strand wrapped in a protein package

Homogenization

- the process of making things uniform or similar

Peptide bonds

A chemical bond formed when the carboxyl group of one molecule reacts with the amino group of the other molecule.

Globules

A small round particle found in a substance.

Harmful

Chemical labelled with this are generally considered to be damaging to humans

Environmentally harmful

Chemicals with this label are damaging to the environment. An example is CFC's

Toxic

Chemicals with this label are highly toxic. An example is mercury.

Corrosive

Chemicals with this label can burn your skin and eyes and burn holes in your clothes. An example is hydrochloric acid.

Flammable

Chemicals with this label can catch fire easily. Example methanol.

Irritant

Chemicals with this label cause irritation to your skin and eyes. An example is hydrogen peroxide.

Oxidizing

Chemicals with this label contains oxygen that may cause other materials to combust. An example is potassium dichromate.

Explosive

Chemicals with this label explode easily. An example is lead azide.

Chromatin

DNA/protein

Ribosomes

RNA/protein

Biochemistry

The study of the chemical substances found in living organisms and the chemical interactions of these substances with each other. Includes compounds, chemicals reactions, and molecular interactions involved in maintenance and reproduction of living organisms. Studies how cells manufacture life and how the chemical reactions by which life is maintained occur.

Residue

a small amount of something that remains

Homogenate

a suspension of cell fragments and cell constituents obtained when tissue is homogenized

Functional groups

atom/group of atoms that show characteristic physical and chemical properties common in biochemistry.

Biomolecules

cells include large molecules such as proteins, nucleic acids, polysaccharides and lipids. - Biomolecules are polymers

Cytoskeleton

fibrous protein structure

Decant

gradually pour from one container into another

Cell membranes

lipid/protein

Homogenize

make uniform or similar

Catalase

· Catalase is an oxidoreductase that acts as antioxidants - Optimum pH: 4.0-8.5; 6-8 for plant catalases - Optimum temp: human body temp; varies in plants but can work around 0-400C · Converts reactive oxygen species (such as H202) to harmless products, such as in the reaction below: 2 H202 - 2 H20 + 02 · The production of oxygen is seen by the formation of bubbles · Catalyze the conversion of hydrogen peroxide to water and molecular oxygen 2 H202 - 2 H20 + 02 · Found in sites of H202 productions such as peroxisomes and abundant in plant storage organs such as potatoes and fleshly parts of fruits. · Optimum temp: 4 - 8.5 for humans; 6-8 for catalase in plants · H202 is a powerful oxidizing agent and is potentially damaging to cells

Pepsin

· Is a hydrolase more specifically a peptidase found in the stomach with optimum pH of 1.6-2.5 · Inactive from pepsinogen is converted to pepsin; this occurs only at low pH which is due to the secretion of HCl by parietal cells in the stomach · Optimum temp: 37o C (humans) · Pepsin has broad specifically with a preference for peptides containing linkages with aromatic or carboxylic L-amino acids. It preferentially cleaves C-terminal to Phe and Leu and to a lesser extent Glu linkages. The enzyme does not cleave at Val, Ala, or Gly. · Pepsin cleaves long polypeptide chains into a mixture of small peptides. In the experiment, addition of HCl will cause the breakdown of the proteins in the egg white. Activate your pepsinogen.

Salivary Amylase

· Salivary a-amylase or ptyalin is a hydrolase · Salivary amylase hydrolyzes the internal (a 1-4) glycosidic linkages of starch, producing short polysaccharides fragments or oligosaccharides. Optimum: pH 7, human body temp (370 C) · In this experiment, a negative I2Kl reaction means amylase has digested starch in the solution.

Enzymes

· are known to catalyze a lot of biochemical reactions · It can increase the reaction rate many million times faster than without a catalyst - mostly globular proteins. Some are simple proteins, some are conjugated proteins · Their action on the substrate can be controlled by adjusting the temperature, pH, or substrate or enzyme's concentration · Since they are proteins, they are also affected by agents that causes them to undergo denaturation.

EFFECT OF STRONG ACIDS

• Hydrogen bonding often involves these side chains. Protonation of the amino acid residues changes whether or not they participate in hydrogen bonding, so a change in the pH can denature a protein. • All proteins have an optimal pH which is dependent on the environment in which it functions • Salt bridges result from the neutralization of an acid and amine on side chains; interaction is ionic between (+) amino group and (-) acid group • Alkaloidal reagents (e.g. tannate, picric & trichloroacetate) are high molecular weight anions (- ). • These reagents combine with (+) amino groups in proteins to disrupt ionic bonds. • The negative charge of these anions counteracts the (+) charge of the amino group in proteins giving a precipitate. ● Purpose ○ Acids and bases can significantly change the environmental pH of proteins, which disrupts the salt bridges and hydrogen bonding formed between the side chains, leading to denaturation. ● Process ○ Increasing the pH by adding bases convert the protonated -NH3+ ion to a neutral -NH2 group ○ Decreasing the pH by adding acids converts the -COO- ion to -COOH group. ○ These changes prohibit the ionic attraction between the side chains, i.e salt bridges, resulting in the unfolding of proteins. ○ The change of protonation status also affects the participation of amino acid residues in forming hydrogen bonds causing the disruption of the protein's 3D structure. ○ Acid-induced denaturation occurs between the pH levels 2 and 5, and base-induced unfolding usually requires pH levels of 10 or higher. ● Steps ○ Add 1ml of concentrated Sulfuric acid (HSSO4) and 1ml of Nitric acid (HNO3) to two separate test tubes containing 2ml of albumin solution. Mix and compare results with the standard.

EFFECT OF ALCOHOL

•Hydrogen bonding occurs between amide groups in the secondary protein structure. •Hydrogen bonding between "side chains" occurs in tertiary protein structure in a variety of amino acid combinations. •Alcohol denatures proteins by disrupting the side chain intramolecular hydrogen bonding. •New hydrogen bonds are formed instead between the new alcohol molecule and the protein side chains. • 70% alcohol solution is used as a disinfectant on the skin • 70% alcohol is able to penetrate the bacterial cell wall and denature the proteins and enzymes inside of the cell. • 95% alcohol solution merely coagulates the protein on the outside of the cell wall and prevents any alcohol from entering the cell. ● 70% ethanol ● Purpose ○ skin disinfectant ○ The concentration of alcohol is able to penetrate the bacterial cell wall and denature the proteins and enzymes inside of the cell ● Process ○ It happens because heat increases the kinetic energy and causes the molecules to vibrate so rapidly and violently that the bonds are disrupted. ● 95% ethanol ● Purpose ○ merely coagulates the protein on the outside of the cell wall and prevents any alcohol from entering the cell. ● Process ○ Alcohol denatures proteins by disrupting the side chain intramolecular hydrogen bonding. ○ New hydrogen bonds are formed instead between the new alcohol molecule and the protein side chains. ● Steps 1. Add 5ml of 70% ethanol and 5ml of 95% ethanol to two separate test tubes containing 2ml of albumin solution. Shake vigorously and compare the result with the standard. 2. Record your observation as slight, moderate, and heavy precipitation

Centrifugation

○ A technique that helps to separate mixtures by applying centrifugal force ○ Sub-fractionalization of the centrifugate

Aspartame or Equal

○ Artificial sweetener, commonly used as a sugar substitute ○ Dipeptide, carboxylic acid and a methyl ester ○ Alpha-carboxyl group of L-aspartic acid with the amino group of methyl L-phenylalaninate

Glutathione capsule

○ Tripeptide comprised of three amino acids (cysteine, glutamic acid, and glycine); antioxidant and detoxifying agent

Test Tube Brush

○ Used to clean the inside of test tubes or graduated cylinders

Molarity (M)

○ amount of a substance in a certain volume of solution. ○ Molarity is defined as the moles of a solute per liter of a solution. ○ Molarity is also known as the molar concentration of a solution

Florence Flask

○ used as a reaction vessel as well as for heating solutions

Wire Gauze

○ used as a support structure and heat diffuser

Water Trough

○ used for containing water when collecting gases

Triangular File

○ used for deburring, cutting glass tubing, and other laboratory uses

Dropper

○ used for drawing up and dispensing drops of liquid

Spot Plate

○ used for evaluating the reaction or response of a substance to observe its behavior under specific conditions

Evaporating Dish

○ used for evaporating and concentrating dilute solutions

Thermometer

○ used for measuring temperature

Crucible Tongs

○ used for removing the lids from crucibles, transferring evaporating dishes or picking small objects out of a reaction container

Erlenmeyer Flask

○ used for stirring, heating or cooling liquids, filtration, storage, and some liquid-handling processes

Spatula

○ used for transferring chemical reagents or other solids

Watch Glass

○ used in a variety of functions inclusive for the evaporation of liquids to prevent the beakers from being contaminated

Clay Triangle

○ used in conjunction with other lab equipment to create a stable framework in which to place a substance while it is heated to a high temperature

Water Bath

○ used in laboratories to incubate samples in water maintained at a constant temperature

Acid Surette

○ used in quantitative chemical analysis to measure the volume of a liquid or a gas

Beaker

○ used in the lab for mixing, heating, and stirring liquid

Wing Top/Flame Spreader

○ used to bend glass in glass manipulation process

Funnel

○ used to channel liquids or fine-grained chemicals (powders) into labware with a narrow neck or opening

Mortar and Pestle

○ used to crush and grind ingredients or substances into a thin paste or powder

Aspirator/Pipette Bulb

○ used to draw different liquids into the pipet

Crucible Cover

○ used to hold reactants during heating at higher temperatures ○ the crucible lid covers it to ensure that nothing enters it during the reaction and that nothing also leaves during the reaction

Utility Clamp

○ used to hold round laboratory glassware, such as a beaker, and flasks

Graduated Cylinder

○ used to measure volumes. It is generally a more accurate way to measure volume than a typical beaker or flask

Bunsen burner

○ used to provide a single, continuous flame by mixing gas with air in a controlled fashion

Distilling Flask

○ used to separate mixtures of two liquids with different boiling points

Stirring Rod

○ used to stir solutions by hand

Ring Stand & Iron Ring

○ used to support the Bunsen burner, iron ring, pipestem triangle, and other items, often while heating a substance

Graduated Pipette

○ used when taking volume of solutions in which accuracy does not have to be very high

Pinch Clamp

○ used with laboratory apparatus for controlling the flow of fluid through flexible tubing

HOMOGENIZATION OF THE LIVER

● 0.025M Sucrose - Prevents osmotic pressure (cause of water) that can cause the swelling of the organelles. The use of pure water may possibly disrupt the organelles ● To rupture the plasma membrane of the cell so that the cell's contents are released

HANDLING CHEMICALS

● All chemicals in the area are to be considered dangerous. Strictly no tasting, and/or smelling ● Check the labels on all chemical bottles twice before use ● Never return unused chemicals to their original container ● Never remove chemicals or other materials from the laboratory area ● Dispose all chemical waste properly ● Labels and equipment instructions must be read carefully before use ● Keep hands away from face, eyes, mouth, and/or body while using chemicals and/or lab equipment ○ Wash your hands after performing all experiments ● All pipetting must be performed with the use of a mechanical device ○ Oral pipetting is to be avoided ● Strong acids. Alkalis, and other toxic substances should always be handled with great care ● Student should develop and display good techniques and working habits such as proper and efficient use of laboratory reagents, equipment and instruments ● Students will be held responsible for careless handling and breakage of glassware and apparatus

BIURET TEST

● Also called Piotrowski's Test ● Is a chemical test for proteins and is used to detect compounds with peptide bonds ● Reagents -KOH, hydrated CuSO4, Potassium sodium tartarate ● Positive result - The solution turns into VIOLET ○ The intensity of the color (pale violet to dark violet) depends on the number of peptide bonds present. ● Negative result - The solution remains BLUE

HOMOGENIZATION PROCEDURE

● Break cells with high-frequency sound ● Use a mild detergent to make holes in the plasma membrane ● Force cells through a small hole using high pressure ● Shear cells between a close-fitting rotating plunger and the thick walls of a glass vessel ● Using gentle mechanical procedures, called homogenization, the plasma membranes of cells can be ruptured so that the cell contents are released. Four commonly used procedures are shown above. ● Homogenate / Extract - the resulting thick containing large and small molecules from the cytosol, such as enzymes, ribosomes, metabolites, and the membrane-enclosed organelles. ● When carefully conducted, homogenization leaves most of the membrane-enclosed organelles intact.

COMMON LABORATORY RULES & REGULATIONS

● Do not consume any food and/or beverage ● Be prepared for any Laboratory work ○ Read all procedures thoroughly before entering the laboratory ○ Never make a mess in the laboratory ● Always work in a well-ventilated area ● Work areas should be kept clean and tidy at all times ○ keep your bags outside ● Be alert and proceed with caution at all times in the laboratory ○ Notify your instructor immediately of any unsafe conditions you may encounter

SAFETY MEASURES: HANDLING GLASSWARE AND EQUIPMENT

● Examine glassware before use. ○ NEVER use chipped, cracked, and/or dirty glassware ● NEVER handle broken glass with your bare hands ○ use a brush and a dustpan and place broken glass in the designated glass disposal container ● Do not immerse hot glassware in cold water ● Never look into a container that is being heated ● Do not place hot apparatus directly on the laboratory desk ○ Always use an insulated pad

NINHYDRIN TEST

● General Test for proteins except for proline (yellow) ● Test for the -NH2 group in free amino acid; Positive Result - a deep blue or purple color solution ● Reagent: ○ Ninhydrin degrades amino acids into aldehydes, ○ Ammonia ○ CO2 (on pH range 4-8) ● Ninhydrin then condenses with ammonia and hydrindantin to produce an intensely blue or purple pigment (Ruhemann's purple) ● Purpose: ○ Performed to detect the presence of ammonia, primary/secondary amines, or amino acids ○ Detect the presence of amines and amino acids in the test solution ○ To quantify the amino acids present in the sample ○ To distinguish carbohydrates from amino acids ● Results: ○ Formation of a deep blue/ purple color, often termed as Ruhemann's purple, in the presence of an amino group ○ In amino acids like proline and hydroxyproline, this test yields an iminium salt, which is yellow-orange in color. ○ Proteins with a free amind group like asparagine react with the ninhydrin reagent to form a brown colored product ○ The intensity of the formed complex is proportional to the concentration of amino acids in the solution ○ Color intensity depend on the type of amino acid present ● Uses: ○ Detect the presence of AA in unknown samples ○ Used in solid-phase peptide synthesis to monitor the protection for amino acid analysis of proteins ○ Used to detect fingerprints ■ It is possible as the terminal amines of lysine residues in peptides and proteins shed off in fingerprints react with ninhydrin

PROTEINS

● Most abundant substance in the cell next to water ● Compromising 15% of its overall mass ● Composed of amino acids as its building blocks linked together with peptide bonds with a positive charged nitrogen-containing group at one end and a negatively charged carboxyl-group. ● Along the chain is a series of different side chains from different amino acids ● Some side chains are neutral, some are acidic, some are basic, and some are classified as polar or nonpolar. ● The different tests in this experiment will help you identify the different types of amino acids present in a protein sample

EFFECT OF HEAT

● Process : - used to disrupt hydrogen bonds and non-polar hydrophobic interactions - occurs because heat increases the kinetic energy and causes the molecules to vibrate so rapidly and violently that the bonds are disrupted. ● Uses : - Proteins in eggs denature and coagulate during cooking. - Other foods are cooked to denature the proteins to make it easier for enzymes to digest them. - Medical supplies and instruments are sterilized by heating the denature proteins in the bacteria and thus destroy the bacteria.

EFFECT OF ALKALOID

● Purpose ○ These reagents combine with positively charged amino groups in proteins to disrupt ionic bonds. ● Examples ○ Tannic acid ○ Potassium-mercuric iodide ○ Phosphomolybdic acid ○ Picric acid ○ Iodine in potassium iodide solution ○ Phosphotungstic acid ● Steps ○ Add 1ml of picric acid, 1ml of tannic acid, and 1ml of 3%TCA solution to three separate test tubes containing 2ml of albumin solution. Shake all test tubes gently and note the color of the precipitate

EFFECT OF HEAVY METALS

● Purpose: - Heavy metal salts, Ag*, Hg*, and Pb* denature by reacting with the sulfhydryl groups to form stable, metal-sulfur bonds. - This prevents the formation of disulfide bonds - Metal ions can also combine with the carboxylate ion on R-groups, preventing their participation in salt bridges. ● Process: - Since salts are ionic, they disrupt salt - Heavy metal + protein > insoluble metal salt ● Uses: - Used for its disinfectant properties in an external application - Silver nitrate, AgNO3 - Used to prevent gonorrhea in the eyes of newborn infants - To treat nose and eyes infections - To cauterize wounds - Mercury salts administered as Mercurochrome or Merthiolate have similar properties in preventing infections in wounds - Used in reverse in cases of acute heavy metal poisoning. - A person may have swallowed a significant quantity of a heavy metal salt - As an antidote, a protein such as milk or egg whites may be administered to precipitate the poisonous salt followed by an emetic given to induce vomiting so that the precipitated metal protein is discharged from the body • Ions form strong bonds with the carboxylate anions of the acidic amino acids or -SH groups of cysteine, disrupting ionic and disulfide linkages. •Heavy Metal Salts Disrupt Disulfide Bonds: •Heavy metals also disrupt disulfide bonds because of their high affinity and attraction for sulfur and which lead to the denaturation of proteins •Heavy metals can disrupt bonds in the protein, causing it to lose its structure. • Salts of heavy metals such as mercury and lead may be used to denature can interact with a protein's functional side chain groups to form complexes. •Heavy metals also oxidize the protein's amino acid side chains •Heavy metals (e.g. Hg2+, Pb2+, Cu2+) are high molecular weight cations. • (+) charge of cations counteracts the (-) charge of the carboxylate group in proteins giving a precipitate.

SAFETY GUIDELINES FOR HOME BASED EXPERIMENT

● Read in advance the experiment you are about to perform ● Never do any unauthorized experiment ● Never perform experiments without wearing Personal Protective Equipment ● Organize the materials before you start your experiment ○ Make sure you are working in a clean and safe area ● Fix your hair with pins or by wearing a hair cap ● Know the location of the fire extinguisher, first aid kit, and shower room just in case unanticipated accidents happen ● Keep flammable chemicals away from your ● Never use lighters for lighting a burner or stove ○ Use match sticks instead ● Wash off immediately with running water because any body part can be affected by chemical spills ● Clean your area after you do your experiments ● Segregate and Label properly the materials that you are going to use for home-based experiments ● Report immediately to your instructor any accidents relating to your experimental work

DIFFERENTIAL CENTRIFUGATION

● Repeated centrifugation at progressively higher speeds will fractionate cell homogenates into their components. ● Centrifugation separates cell components on the basis of size and density. The larger and denser components experience the greatest centrifugal force and move most rapidly. They sediment to form a pellet at the bottom of the tube, while smaller, less dense components remain in suspension above, a portion called the supernatant 1st Centrifugation Sediment 1: Unbroken cells, nuclei Major biomolecule: DNA - Nucleic Acid 2nd Centrifugation Sediment 2: Mitochondria, Lysosomes, peroxisomes Major biomolecule: Carbohydrates 3rd Centrifugation Sediment 3: Microsome, and other small vesicles Major biomolecule: Lipids, proteins Supernatant 3: Proteins and some inorganic ion

HOPKINS-COLE TEST

● Test for indole group, tryptophan ● Reagents ○ Hopkin's Cole reagent ○ Sulfuric Acid (H2SO4 ) ● Positive Result - Purple ring at the interface of two liquids ● Dehydration of tryptophan, only amino acid with indole group ● Reacts with the reagent glyoxylic acid in presence of H2SO4 ● Purpose: ○ Performed to detect the presence of ammonia, primary/secondary amines, or amino acids ○ Detect the presence of amines and amino acids in the test solution ○ To quantify the amino acids present in the sample ○ To distinguish carbohydrates from amino acids ● Result: ○ Formation of a deep blue/purple color, often termed as Ruhemann's purple, in the presence of an amino group ○ In amino acids like proline and hydroxyproline, this tests yields an iminium salt, which is yellow-orange in color ○ Proteins with a free amind group like asparagine react with the ninhydrin reagent to form a brown colored product ○ Intensity of the formed complex is proportional to the concentration of amino acids in the solution ○ Color intensity depend on the type of amino acid present ● Uses: ○ Detect the presence of AA in unknown samples ○ Used in solid-phase peptide synthesis to monitor the protection for amino acid analysis of proteins ○ Used to detect fingerprints ○ It is possible as the terminal amines of lysine residues in peptides and proteins shed off in fingerprints react with ninhydrin

SAKAGUCHI TEST

● Test for presence of arginine in either free form or in proteins ● Reagents ○ Sodium hypobromite ○ 1-napthol ● Results ○ Positive Result - Presence of red colored complex, presence of arginine or guanadium compound. ○ Negative Result - Absence of red colored complex and arginine or guanadium compound. ● Using gentle mechanical procedures, called homogenization, the plasma membranes of cells can be ruptured so that the cell contents are released. Four commonly used procedures are shown above. ● Homogenate / Extract - the resulting thick containing large and small molecules from the cytosol, such as enzymes, ribosomes, metabolites, and the membrane-enclosed organelles. ● When carefully conducted, homogenization leaves most of the membrane-enclosed organelles intact. ● Purpose ○ Is a test consisting of colorimetric reaction for the detection and quantification of guanidinium groups, used as a qualitative test for arginine that is either free or in protein ○ This test is an example of color reactions or test that is performed for the detection of amino acids or proteins ○ Specified test for arginine where the guanidinium group of arginine reacts with 1-naphthol or a-naphthol to produce a colored product ○ Is a qualitative test, and the quantification of arginine is hindered in this test due to the slow rate of color development and destruction of some guanidinium groups by the reagent ○ To detect the presence of arginine in either free form or proteins.

XANTHOPROTEIC TEST

● Test for the detection of amino acids containing phenolic or indolic groups like phenylalanine, tyrosine, and tryptophan (aromatic amino acids). ● Reagents ○ Conc. Nitric Acid ○ Sodium Hydroxide ● Results ○ Positive Result - Appearance of a dark yellow or orange-colored solution indicates the presence aromatic groups in the proteins and amino acids ○ Negative Result - Absence of a dark yellow or orange-colored solution indicates the absence of aromatic groups in proteins and amino acids ● Purpose ○ To detect the presence of aromatic group-containing amino acids like tyrosine and tryptophan ○ To differentiate tyrosine and tryptophan from other amino acids ● Uses ○ This is a biochemical test for the detection of proteins and amino acids ○ The test allows the differentiation of aromatic amino acids and non-aromatic amino acids

BIURET TEST(Protein)

● The general test for proteins, detecting peptide bonds ● Reagents: ○ KOH ○ hydrated CuSO4 ○ Potassium sodium tartrate ● Positive result - Violet solution ● the blue color of a basic solution of Cu2+ turns to a violet color when a tripeptide or larger peptide is present. ● The NaOH is there to raise the pH of the solution to alkaline levels; the crucial component is the copper II ion (Cu2+) from the CuSO4 . ● Purpose: ○ Used determine the presence of a peptide bond in a substance ○ General test conducted for compounds (proteins and peptides) having two or more peptides (CO-NH) bonds. ● Results: ○ Positive result produces violet colour once treated with (alkaline) copper sulfate (proteins are present) ○ Peptide bonds in Biuret give a positive result for the test hence the reagent is named so ○ Negative result no color change (proteins are absent) ● Uses: ○ Detect the amount of protein in urine ○ Quantitative determination of total protein by spectrophotometric analysis

PROTEIN DENATURATION

● The modification in confirmation of protein, accompanied by disruption and possible destruction of secondary, tertiary, and quaternary structure of protein. ● Brought upon by different types of agents like heat, mechanical disturbance, inorganic and organic substances, etc. ● Loss of solubility in water is the frequent consequence of the protein denaturation. ● When denatured protein precipitates out, this is called coagulation • Protein denaturation is the partial or complete disorganization of a protein's characteristic threedimensional shape • Result of disruption of its secondary, tertiary, and quaternary structural interactions. • Because the biochemical function of a protein depends on its three-dimensional shape, the result of denaturation is loss of biochemical activity. • Protein denaturation does not affect the primary structure of a protein. • Some proteins lose all of their three-dimensional structural characteristics upon denaturation, most proteins maintain some 3D structure. • Renaturation - limited denaturation changes conditions can be reversed, in which the protein is "refolded,". • For extensive denaturation changes, the process is usually irreversible. • Loss of water solubility is a frequent physical consequence of protein denaturation. • Coagulation or precipitation out of biochemical solution of denatured protein • Protein denaturation involves loss of the protein's threedimensional structure. Complete loss of such structure produces an "unstructured" protein strand.

SAFETY MEASURES: CLOTHING

● Wear safety goggles everytime chemicals, heat, and/or glassware is used ● Contact lenses should NOT be worn in the lab. ● Dress properly during lab activities ○ Long hair must be tied back ○ Dangling jewelry, and loose/baggy clothing must be secured ○ Shoes must completely cover the foot ○ A lab coat should be worn

Heat

● disrupt hydrogen bonds and non-polar hydrophobic interactions ● Heat increases the kinetic energy and causes the molecules to vibrate so rapidly and violently that the bonds are disrupted • proteins in eggs denature and coagulate during cooking. foods are cooked to denature the proteins to make it easier for enzymes to digest them. • Medical supplies and instruments are sterilized by heating to denature proteins in bacteria and thus destroy the bacteria. •High levels of thermal energy may disrupt the hydrogen bonds that hold the protein together •As these bonds are broken, the protein will begin to unfold and lose its capacity to function as intended • Temperatures at which proteins denature may vary, but most human proteins function optimally at body temperature (37 degree centigrade)