• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

The Effect of pH on the Strength of Keratin (hair protein).

Extracts from this document...

Introduction

Science Plan The Effect of pH on the Strength of Keratin (hair protein) Relevant Information: Keratin is a fibrous protein and has a structural function. Fibrous proteins contain polypeptides that bind together to form very long fibres running parallel to each other. These fibres are linked by cross-bridges that make the protein strong and insoluble. The main constituent of hair is the protein keratin. Keratin can also be found in horns, nails, claws and feathers. These examples suggest keratin has a strong structure. Like most other proteins it is made of monomers called amino acids. All Amino acids contain both an acidic carboxylic group (-COOH) and a basic amino group (-NH2); there is also an R group that changes with each different amino acid. They all consist of carbon, hydrogen, oxygen and nitrogen atoms. Keratin also contains a high concentration of the amino acid cysteine; this contains a sulphur atom. The sulphur atoms from two cysteines join together, forming a very strong disulphide bond. These bonds are covalent and form strong links making the tertiary structure of the protein very stable. The disulphide bonds occur down the length of the keratin fibre and the cross-linking between the keratin chains account for the strength of hair. ...read more.

Middle

The five test dishes will be cleaned in pH neutral solution and rinsed with distilled water, this is to prevent contamination. The five pH solutions will have varying values across the pH scale. A strong acid (pH 1-4), a weak acid (pH 4-6.4), a neutral (pH 7), a weak alkali (pH 7.5-9.9) and a strong alkali (pH 10-14) will be used to test individual hairs. This range is representative of the principal pH values. The chemical compounds chosen to represent these pH values are Hydrochloric Acid, Acetic Acid, Water, Calcium Hydroxide and Sodium Hydroxide respectively. These compounds are commonly used in the laboratory and practical to obtain. Also their pH values correspond to the values chosen to test. Each test dish will have a 2cm3 chemical solution with a concentration of 0.5M. This concentrate is the safest amount to use whilst still getting a strong pH. The five separate experiments will be conducted simultaneously so that all the conditions are the same. The dishes and splints must be labelled accordingly with their pH values. The corresponding splint will be placed into the solution, the hair is to be exposed for 10 minutes, to ensure that the hair has been exposed thoroughly. The hair will be removed gently and rinsed with distilled water and allowed to stand to air dry. ...read more.

Conclusion

A laboratory coat is also to be worn. Hair tied up. Keep at a distance from bases. General Use: Wear eye protection and gloves. Used with careful supervision. Acetic Acid- CORROSIVE Causes severe burns; avoid contact with liquid or vapour in the eyes, on the skin, by breathing, or on clothing. Solution to be kept in a cool place and avoid liquid or vapour contact. In the 0.5M solution to be used the chemical is an IRRITANT. General Use: Gloves must be worn and protective eyewear as a precaution. Use bottle carriers for transporting acid bottles. Segregate acids from bases. Calcium Hydroxide- CORROSIVE Inhalation causes irritation to the respiratory tract. Symptoms may include coughing, shortness of breath. Calcium hydroxide is CORROSIVE General Use: Gloves and eyewear must be worn at all times to reduce exposure to hands. Sodium Hydroxide- CORROSIVE Causes severe burns. Very dangerous to eyes and skin. Solution will be equal to 0.5 M and should be labelled CORROSIVE. General Use: Eye protection is very important. The solution must not be handled directly. The use of beakers with handles is safer, as they are less likely to be dropped Ethical Implications: The donor of the hair, must consent to the manner the hair will be used and agree with the testing. The hair should be chosen from a healthy individual who does not suffer from a hair disorder. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Aqueous Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

4 star(s)

A good description of the plan including detailed, relevant background theory. The method could be improved by describing fully how all control variables are to kept constant so that only changes to the independent variable should affect the results.

Marked by teacher Adam Roberts 14/10/2013

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Aqueous Chemistry essays

  1. Marked by a teacher

    Determine the solubility product of calcium hydroxide

    3 star(s)

    The solubility of an ionic compound is indicated by the Ksp value of Ca(OH)2, the smaller the value, the less solubility the compound is in water. When the Ksp increases, the pOH decreases, pH increases, the Hydroxides become more soluble, and the [OH-] becomes greater.

  2. Investigating the heating and cooling curves of stearic acid wax.

    After this, the temperature recordings were forming a smooth curve, however, when it was at 60C�the temperature rapidly increased by 41C� in one minute, there wasn't a smooth curve in my graph. As the temperature was cooling down, there was another odd results, as again, I was expecting the solidifying

  1. To investigate three factors that affect the rate of cooling a liquid and to ...

    The water can only cool at a certain speed in one condition and as all the beakers had the same conditions the heat transfer rate remained the same in all the beakers. Therefore if there is less water, then the water will cool more quickly and if there is more water it will take longer to cool.

  2. Determine Solubility of KClO3 Salt.

    Apparatus and Materials: * * KClO3 salt * Distilled water * Pestle and mortar * Measuring cylinder/ Graduated cylinder (100cm3) * Beaker (500cm3) * Porcelain dish * Thermometer * Analytical Balance * Oven * Pipette (>5-mL) Procedures: 1. About 2g of KClO3 salt are grind in a mortar by using a pestle.

  1. Quantitative test for starch and reducing sugar present in apple and pear

    This method is effective in comparing the amount of reducing sugar present in two kinds of food, yet it was very time-consuming to test for a suitable concentration for the test. Both tests were able to compare the amount of reducing sugars or starch present in the fruits, yet they

  2. Investigating the effects of varying pH levels on the germination of cress seeds

    0 100 RISK ASSESSMANT Acids can cause burns and irritate the respiratory system. Eye protection should be worn. Sulphuric Acid: Very corrosive; causes severe burns. Solutions equal to or stronger than 1.5 M should be labelled 'corrosive'. Can be dangerous when mixed with water; always add acid to water (never the reverse)

  1. The aim of this experiment is to answer the following question: What is the ...

    Also the water baths will be set so that there is an element heating the water. This must not be touched as it can cause burns. Also the water may too hot to touch so, the water must be touched as little as possible.

  2. AIM: To study the effect of solid impurities on boiling point of water and ...

    Heat the beaker on a Bunsen burner with a wire mesh and thermometer inserted in it till water starts boiling observing the temperature after every 10 seconds 1. Record this observation as boiling point of water in the table 1.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work