Chemistry for Biology Technicians

Unit 27: Chemistry for Biology Technicians Unit code: K/502/5557 QCF Level 3: BTEC National Credit value: 10 Guided learning hours: 60 Aim and purpose This unit aims to provide learners with an understanding of the principles of chemistry for biology technicians and how these can be put into practice. This unit is primarily aimed at learners within a centre-based setting looking to progress into the sector or to further education and training. Unit introduction Biology technicians perform an enormous range of tasks including caring for a variety of animals, plants and other organisms, and preparing tissue slides in anatomy departments or pathology laboratories. They carry out microbiological tests on water or pathology specimens, make vaccines, grow cell cultures, work in infection control, investigate blood smears, carry out biochemical tests and analysis of DNA. Biological knowledge continues to increase exponentially. In the 1970s, many textbooks would simply describe processes, explaining that underlying mechanisms were not fully understood. This has changed dramatically in recent years. Biological processes work because of the underlying chemical processes. An understanding of chemistry is needed for any scientific role. If learners understand units of concentration, they will feel more confident in making up or diluting a solution. If they understand the nature of chemical bonding, they will know why certain solvents are used in processing tissue samples. Knowledge of chemical formulae is needed to ensure that correct chemicals are used. Learners need to understand rates of reaction and equilibrium to see why standard laboratory protocols may have timed steps. These biological processes are complex and require a good understanding of chemistry. This unit covers some of the basic chemical concepts so learners can begin to understand and explain biological processes. Learning outcomes On completion of this unit a learner should: 1 Be able to relate enthalpy changes to the bonding in a range of substances 2 Be able to show how rates of reaction are affected by varying the reaction conditions 3 Be able to interpret key features of equilibrium processes 4 Be able to demonstrate the structure and properties of simple organic molecules. Edexcel BTEC Level 3 Nationals specification in Animal Management – Issue 1 – August 2010 © Edexcel Limited 2010 2 Unit content 1 Be able to relate enthalpy changes to the bonding in a range of substances Bonding: ionic; covalent; hydrophilic and hydrophobic interactions, electronegativity; dipoles; hydrogen bonds; van der Waals forces; intermolecular and intramolecular forces Substances: salts; salt solutions; water; organic molecules; solids; liquids; gases; emulsions Physical properties: solubility; melting and boiling point Enthalpy and enthalpy change: system and surroundings; units of enthalpy change; standard conditions; exothermic and endothermic reactions; reaction profiles; activation energy; Hess’s law; HendersonHasselbalch equation 2 Be able to show how rates of reaction are affected by varying the reaction conditions Reaction rates: units (mol dm-3s-1); orders of reaction; rate constant, reaction mechanisms, rate determining steps; reaction profiles, activation energy Factors influencing rates: collision theory; effects of changing concentration, particle size, surface area, temperature, addition of a catalyst (including enzymes) Quantitative chemistry: calculations based on mass, mass of one mole and number of moles; calculations based on number of moles, volume and concentration; dilution; units (mol, dm3, cm3, mol dm-3, g, g mol-1) Practical work: reaction rates under varying reaction conditions eg enzyme kinetics/magnesium and hydrochloric acid/zinc and sulphuric acid 3 Be able to interpret key features of equilibrium processes Chemical equilibrium: principles of equilibrium; equilibrium constants Proton concentrations: pH eg Kw; strength of acids and bases; Ka, pKa; calculations of pH from Ka, and Ka from pH; conjugate acid and base; effect of pH on amino acids; action, mechanism and biological importance of buffer solutions Concentrations either side of a membrane: diffusion and osmosis in terms of water potential (ψ); membrane potential; diffusion of gases Redox processes: oxidation and oxidation states; reduction eg displacement reaction of metals; construction of half equations and redox equations for simple redox reactions; salt bridges; standard electrode potentials, Eө; standard conditions; sign convention 3 Edexcel BTEC Level 3 Nationals specification in Animal Management – Issue 1 – August 2010 © Edexcel Limited 2010 4 Be able to demonstrate the structure and properties of simple organic molecules Functional groups: nomenclature and classes of compounds: alkanes, alkenes, alcohols, alkyl halides, carboxylic acids, aldehydes, ketones, esters, amines, amides; tests for and recognition of functional groups in complex molecules Structure: tetrahedral carbon; carbon-carbon double bonds; isomerism (structural, eg chain, positional, functional group), geometric, optical (chiral carbon, importance in natural systems); IUPAC nomenclature; monosaccharide and disaccharide structure Properties: solubility of alkanes, alcohols and sugars; simple reactions of organic compounds (addition reactions for alkenes, oxidation of alcohols to aldehydes and ketones, oxidation of aldehydes to acids, carboxylic acids as acids, esterification, amines as bases, formation of amides