Biology B3 Topic 1

a set of revision cards for those taking biology b3 structured paper edexcel in may.extension units.

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Introduction to Biotechnology

Biotechnology: Bio=life and technology   Biotechnology=using living organisms to make products,soy sauce,apple cider)food industry has been using micro organisms to produce cheese,chocolate,alcohol,etc.more recently weve started using microproteins.also used for medicine(antibiotics)


  • provides genetic engineering techniques-improving food crops
  • provides molecular breeding methods-improving livestock
  • use of stem cells to treat disease such as lukemia


  • some regarded unethical such as cloning
  • discrimination against people with genetic diseases or medical anomalies.
  • exposure of animals to genetically modified crops -super species
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production of yoghurt

Production of yoghurt:

key words:fermentation,yoghurt,lactobacillus,aspergillus oryzae,pasteurised


  • equipment is sterilised-kill unwanted micro organisms
  • milk is pasteurised(heated either at 72C for 16s or 65C for 30minutes)-to kill unwanted micro-organisms.milk is then cooled down to 37C(body temp).
  • Yoghurt bacteria (Lactobacillus)added to milk as a starter culture.
  • mixture incubated (heated about 40C)in a fermenter.
  • Fermentation is carried out by Lactobacillus to turn the lactose sugar in the milk to lactic acid.Lactic acid causes the milk to clot and solidify into yoghurt.Lactic acid gives yoghurt its sharp taste.
  • sample is taken to ensure right consistenty.
  • colours and flavours could be added before packaging
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Production of Soy Sauce

Production of Soy Sauce:

  • Soy beans soaked,then pressure cooked
  • Resulting mash mixed with flour derived from roasted wheat
  • The mixture is spread out on warm shallow trays and supplied with air.
  • Culture of the fungus aspergillus orzae(mould) added.mould is added as it produces enzymes(anylase) that catalyze the breakdown of protein into amino acids and carbohydrates(starch into glucose) in the mixture.
  • It is then incubated for three days at 30C with brine(concentrated salt)and acts as a preservative.
  • yeast is added which also secretes enzymes[produces alcohol and water so soya sauce is slightly alcoholic} and lactobacillus bacterium is also added[ensuring levels of oxygen in mixture are kept low and it also stops the mould and yeast from secreting enzymes].
  • solids are filtered [liquid cleared of any sediment] and sour brown liquid is collected.
  • liquid is then pasteurized(to kill microbes) and stored in sterile bottles.
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Functional Food

Functional food: food that has some kind of health benefit beyind basic nutrition.e.g it might prevent some kind of disease.

Plant stanol esterts  are chemicals found in plants that can lower cholesterol levels and reduce the risk of heart disease.They are produced commercialy by using bacteria to convert sterols(type of fat in plants)to stanols.Food manufacturers add them to spreads and other dairy products.

Prebiotics are microbes that favourably influence the health of the host.They are non-digestable food components that increase the growth of the probiotic organisms (lactobacillus & Bif Idobacterium) in the gut).Prebiotics [non digestable food components].They cannot be digested by harmful bacteria and humans as they dont have the right enzymes.


  • statins-found in plants linked to lowering cholesterol levels which in turn causes hear disease.
  • oligosacharrides-carbohydrate found naturally in leeks/onions and is food for the healthy bacteria that breaks down toxic compunds in our guts.Although they occur naturally in leeks and onion they are not enough in a normal diet to have a significant effect-people take supplements.
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Using Microbes to Alter food

Microbes are used to produce microbial products that are added to food to:

  • prolong shelf life
  • improve flavour
  • improve texture
  • improve appearance
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Examples of microbial products used to produce foo

Microbial product:invertase (enzyme)

Production:naturally produced by a yeast called saccharomyces cerevisiae.

Function:converts the sucrose(a sugar)into glucose and fructose (differen types of sugar which are sweeter.)-meaning less sugar is needed for the same sweetness[manufacturers save money and produce lower calorie sweet foods.]            

Usage:to make soft centres of chocolates like semi solid chocolates and sweets.

Microbial product:Chymosin(enzyme)

Production:naturally found in rennet which is traditionally obtained from the lining of a calf's stomach.However,vegetarian cheese is made using chymosin from genetically modified microorganisms[genes responsible for chymosin taken from calf stomach cells and put into yeast cells which then are grown on an industrial scale to produce chymosin.

Function:clots the milk to form cheese                                    Usage:to make cheese

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Example of microbial products that is eaten [vitam

microbial product: vitamin C[E300] 

production:   naturally extracted from fruit  

                      Acetobacter(bacterium) produces a chemical that  is easily converted to vitamin C.

Function: breaks down glucose using enzyme.                                             

Usage: as dietary supplement (vitamin pills).

            to increase shelf life of foods such as drinks and bread.

microbial product:citric acid(E472c) preservative and flavouring

Function:gives a sharp taste and preserves the product

Production:naturally found in citrus fruit.However aspergillus niger is used to produce citric acid commercialy.

Usage: in flavoured fizzy drinks where it has to be added seperately

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Example of microbial products that is eaten[MCG an

Microbial product:MCG or Amino acids(glutamic acid E621)

prouction:made from glutamic acid and produced by the bacterium corynebacterium glutamicum.

function:bacteria secretes glutamic acid into the medium they ar grown in.The glutamic acid is then used to make monosodium glutamate(a sodium salt).

usage:flavour enhancer and supplements for body builders

Microbial product:carrageenan [E407]

production:naturally found in seaweed carrageen

function:gelling agent

usage:make organic glue,agar plates & crackers also used as an emulsifier in foods.

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Diet and obesity

Balanced diet is a diet that supplies all 7 essenial nutrients that help you function properly:

Nutrient:carbohydrates-functions:provide energy(e.g. glucose)

Nutrient:Fats-functions:provide energy,act as energy store,provide insulation,form cell membranes and steroid hormones.

Nutrients:Proteins-functions:for growth and repair of tissue and to provide energy in emergencies.

Nutrients:Vitamins-functions:various depending on type e.g. vitamin C maintains healthy connective tissue.

Nutrients:Minerals-functions:various depending on type e.g. iron produces haemoglobin for healthy blood.

Nutrient:Water-funtions:needed for constant hydration and replace loss of water in the body.

 4 food groups are: fruits and vegetables,bread and cereals,milk and dairy products,and meat and alternatives

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Diet and obesity

Problems of an unbalanced diet(you get too much of some nutrients but too little of others)-this is called malnutrition

most common form of malnutrition are deficencies:

protein deficiency-can cause a condition called kwashiorkor which is a big problem in developing countries(protein rich foods are too expensive or not available).

vitamin deficiency-can cause loads of problems such as scurvy which you get if you dont have enough vitamin C.

mineral deficiency-can be pretty bad-lack of iron in the blood can cause anaemia which is a blood disorder-where red blood cells dont carry enough blood to the rest of your body.

but not all malnutrition is a deficiency:

e.g.excess carbohydrates and fat causes obesity.

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Diet and obesity

Body mass index(BMI)=body mass(kg)/body height (metre squared)

20-25 is the ideal BMI for a healthy lifestyle

Obesity and anorexia:

obesity is a common disorder-it is defined as being 20% or more over recommended body weight for their height.People who have a body mass index of 30 or more are said to be obese.too much sugary and fatty foods and too little exercise are the main causes of obesity.obesity increases the risk of diabetes,high blood pressure and heart disease and some forms of cancer.However if weight is going to be lost it has to be gradually.

Anorexia is caused by not eating enough sugary and fatty foods.It can lead to vitamin and mineral deficiencies e.g osteoporosis weakened bones and infections due to a weak immune system.

Cholesterol levels in the blood must remain low as if they get too high they will gather on the arteries' walls and clot them.Arteries carry oxygenated blood to the heart so if they clot the levels of oxygen will decrease and there is a greater risk of heart disease.

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Genetic modification to feed the world

Genetically modified(GM): a species in which genes are transferred.The process in which the gene is transerred is called genetic modification using genetic engineering techniques.

Many people in developing countries are not getting enough food to eat and suffer from malnutrition. Reasons for this is: war(force people of their land),drought(causes crops to fail),poor soil(lack of nutrients causes crops to stop growing),pests(destroy crops e.g locusts),and being dependant on one crop(lead to nutritional deficiencies).

Plant breeding programmes are used to produce high yielding crops.This is a type of selective breeding programme .where plants with desirable characterstics are cross bred and then allowed to repoduce asexualy.However this is quite a slow process.

Genetic engineering can produce more food of better quality faster.Crops can be gentetically modified to be resistant to pests.They can be genetically modified to grow in harsh environments such as droughts.Some crops can be genetically modified to combat deficiency diseases.For example in parts of the world where they rely heavily on rice which doesnt contain a lot of vitamin A so rice is genetically modified to contain vitamin A.

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Views and Disadvantages of GM crops


  • Some people think that people in developing countries are not hungry because there are not enough food but because they cant afford food.So poverty should be dealt with first.
  • Some people think that selling GM crops for profit could help deal with poverty.
  • There are fears that countries may become too dependant on GM seed selling companies.
  • Sometimes, in the case of poor soil even GM crops fail.


  • transplanted genes might get into the environment producing herbicide resistant"super" weeds.
  • GM crops could affect the wildlife variety so reduce biodiversity.
  • Not everyone thinks GM crops are safe-for example they could cause allergies.
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GM herbicide resistant crops

Agrobacterium tumefaciens is a bacterium which lives in the soil.This bacterium is used as a vector to transfer genes controlling the herbicide resistance gene into the genetic material of plants.


  • You get a plant which is resistant to herbicide.Therefore it contains a gene which controls herbicide resistance.
  • The herbicide resitance gene is cut from the plant cell(chromosome) using restriction enzymes.
  • The Agrobacterium cell contains a loop of DNA called the Ti plasmid(Ti stands for tumour inducing) this is also taken out and cut open using restriction enzymes.
  • Ligase enzyme is used to insert herbicide resistant gene into Ti plasmid.
  • Ti plasmid with resitance gene is inserted back into Agrobacterium tumefaciens.
  • Bacterium infects the plant causing it produce a crown gall(a growth of cancerous plant tissue).The genetc material of the crown gall contains the genetic material of the Ti plasmid with the herbicide resistance gene in place.
  • Pieces of tissue are cut from the crown gall.
  • Culture of crown gall cells, each containing the modified Ti plasmid as part of its genetic material.
  • Gall cells grow into plants restistant to herbicide.
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Medicinal Plants (Drugs)


traditional medicine:plant base medicine

trial and error:extracting a substance from a plant and observing the effect of the substances given to the ill patients.

active ingredient:A substance which is responsible for relieving the medical problem,fever,pain etc...

Production of drugs: A lot of our current medicines were discovered by studying plants used in traditional medicine.Scientist do this by identifying promising plants then looking for an active ingredient.Scientists also screen plants for anything useful.Some scientists think that a cure for most diseases exists in nature.

Name:Vincristine and vinblastine Source:Rosy Periwinkle Usage:anti cancer drug


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Name:Curare Source:Strychnos plant Location: Amazon rainforest Function:relaxes muscles Usage:Hunter-diped into dart and used to shoot animals they eat.The animals breathing muscles stop,they suffocate and fall to the ground.

Name:Aspirin(1828-1899 launched) Source:compund called salicin Location:leaves and bark of willow trees Function:reduces swelling in joints,fever,blood clots and pain.However salicin can be converted to salicylic acid which damages the lining of the stomach and the intestines.

Name:Quinine(1600-1860 launched)Source:Cinchona tree bark Location:south america Function:lowers body temp and kills plasmodium parasites in RBC's.Usage:treat malaria[disease caused by plasmodium]Plasmodium is carried by female Anopheles mosquitos that feed on RCB's.

Name:Artemisinin(Chinese launched 1972)Source:leaves from Artemisia annua Location:China and SE Asia Function:cancer[reduces blood supply to tissue]and malaria[kill and prevent plasmodium from reproducing inside its vector].Usage:newer antimalarial drug to treat skin diseases. Can be genetically engineered using yeast cells.

Name:Taxol(discovered by scientists screening trees for treatments)Source:Pacific Yew tree Function:prevents cells from dividing Usage:anti cancer drug Semi synthetic version of taxol produced called paxitaxel in 1995.However pacific yew tree is protected and slow growing so have to find other ways to produce taxol.

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Drug Development

Modern drugs are expensive to produce.Hence when companies produce a new drug they take out a patent on it-only they can make it and sell it for a certain number of years. This allows the company to make the money lost in research and development of the drug.Some people say the patent means the company can charge what they like.This is controversial-not everyone who needs the drug can afford it under patent.

Views: Against: 

  • drug companies could charge less and still make a profit(some drug   companies are giving developing countries discounts).
  • making any profit from people's illnesses is unethical
  • other companies should be allowed to copy the drugs and reproduce them cheaply(it'd save lives now but might jeapordise further development of drug later).


  • it'd be unfair for other companies to make and sell the drug more cheaply-they didnt do any expensive research(profit from successful drugs has to cover the costs of research on drugs that are rejected in trials).
  • there'd be no reason for a company to develop new drugs if they cant make a profit.
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Gene Doctor

Keywords: Human genome-the complete genetic make-up of a human(all the genes found in a human).

Genomic-the study of genomes and their uses.Genomics could have various uses in medicine and agriculture.Its use in medicine could be that it tries to predict how likely a person is to suffer from a disease and how they will react to a particular drug.

Human Genome Project found out all the genes present in humans.HGP showed that we dont know about genes as we thought we did.E.g humans olny have 25000 genes(far fewer than predicted).Although we know where all our genes are,we dont know what all of them do.

Bioinformatics-involves the use of computers to match the base sequences of the genome with the proteins for which they code.

Pharmacogenics-matches the design of a drug to an individuals genome,which affects the individuals response to the drug and helps to maximise its effects.

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Medical uses of Genetics

  • All diseases depend on genes,finding out which genes we have,could lead to preventive measures or early treatment.
  • We could be able to identify defective genes and so understand how a disease is caused.Thus leading us to find how to treat it-new drugs or gene therapy.
  • We could tailor drugs to an individual's genes so the treatment is more effective and there are less side effects.

Pathogen's genes:

  • Scientists are also investigating the genome of pathogens- to find out *********** them.
  • For example developing drugs to target certain parts of the pathogen(chemical pathways) causing it to die(drug targets).

Pharmacogenics offers the potential to match an individual's genetic profile to a particular variety of a drug which best suits that individual.Eventually it will be possible to personalise drug treatments based on an understanding of our individual variations.

Advantages: safer drugs-fewer allergic reactions to genetic materials.treatment target particular diseases-more accurate drug doses. less likely adverse reactions-better medicines treatment based on how well body proccesses medicines rather than age and body weight-better vaccines

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GM bacteria producing medicines

Human insulin is produced by GM bacteria.The human insulin is extracted and used to treat the disease diabetes.

Blood clotting factors are now produced in a similar way.

Advantages-Its cheaper,easier to use and you get large amounts of the proteins.These are of the human form,so no need for any immune reactions or risk of catching animal diseases.less likely to be rejected.

Method:-Gene for human insulin identified and cut using restriction enzymes.A circular molecule of DNA(plasmid)also cut using restriction enzymes.Ligase enzymes used to stick the human gene into the plasmid at sticky ends(sections where the plasmid and the human gene stick together).

Plasmid inserted into the bacterium Escherichia coli.The bacterium now starts to produce the chemical insulin.Insulin is a hormone and a protein made in the pancreas.

Bacteria are grown in large fermenters with optimum conditions(37 body temp) for maximum "pro insulin" production.

Bacteria is killed by sterilisation.Insulin is extracted and purified for use by people with diabetes so that it does not contain any GM components.

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IVF is used to help couples who cant conceive have a baby.Two or three fertilised eggs are chosen for implanting back to the women's womb.The embryos consist of a ball of cells.

Reasons for infertility:

  • some women cant produce eggs(damaged ovaries or fallopian tubes)
  • some women can produce eggs but always miscarry.
  • some men cant produce healthy sperms

In vitro fertilisation(IVF) is when a women's eggs and a man's sperm are fertilised outside the body.You can used donated eggs or sperm or you can have a surrogate mother who carries the baby to date.

Some people say that IVF is not natural.Not all fertilised eggs are implanted into the mother some are thrown away(denying life) and some are used for medical research(allowed up to 14 days seen as controversial).Increases the chances of mutliple pregnancies-a danger to mum and can cause financial problems octomom.surrogate mother might not want to give up child.

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Embryo screening

Keywords:Designer baby-creating a baby with desired characteristics Eugenics:only couples with the desirable characteristics are allowed to have chidren. Embryo:ball of cell formed after fertilisation of egg and sperm.

A cell can be removed from an embryo during IVF to analyse its genes.This is done without harming the embryo.It could test for genes that could cause disease.Only embryos which are free of faulty genes are chosen to be implanted.This can also find out the sex of the child which could help if there is a family history of inherited disease that occurs in males (Duchenne muscular dystrophy) or brest cancer in females.To select the sex of the baby,doctors can either test the embryonic cells to see which chromosomes are present or sperm can be selected according to X or Y chromosome present.The Y chromosome is smaller than the X chromosome.The chromosomes decide a person's sex.


  • it will detect other charasteristics such as (eye colour)as well a diseases.could lead to eugenics.
  • not natural
  • could lead to unbalanced population (skew balance of boys and girls)or perfect race(hitler)
  • could lead us to producing desiner babies
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Stem cell research

Keywords:stem cells-cells that can change do become any type of cells(unspecialised) before differentiation.

Differentiation:the process in which a cell becomes specialised in a job.

Embryonic stem cells-undifferentiated cells found in an early human embryo.can be used to treat spinal cord injuries,heart attacks,muscle failure in the heart,blindness baldness,diabetes,alzeihmers and parkinson's disease.Can also be potentially used to create tissue and eventually maybe even organs.(woman which trichea was made of stem cells).

Adult stem cells are found in the bone marrow however are less versatile than embryonic stem cells and can only be differentiated into certain types of cells.are being used to treat sickle cell anaemia,leukaemia,and lymphoma.

Parkinson's disease is caused by a small cluster of cells in the brain which produce a neurochemical transmitter called dopamine.When these cells die and stop working they stop producing enough dopamine.This affects muscle control and results in uncoordinated jerky movements.Can also lead to paralysis.A dose of stem cells might also help regrow health brain cells.

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Views on Stem cells

For :

  • helps people suffering from diseases now so their rights are seen as more important than the embryos.
  • embryos are only a potential life-they cant survive on their own yet
  • only unwanted embryos are used-they would have been thrown away and destroyed anyways if they werent used in research.
  • Nowadays scientists are using stem cells from the placenta(from afterbirth)not embryos.


  • embryos used have a potential to life.
  • it is banned in some countries-Uk it follows strict guidelines.
  • Governments are paying thousands of pounds to buy stem cells-government could be using that money to feed the hungry,military,or for homeless.
  • Treating humans as "cell factories" is immoral-life is given and not bought.
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Cloning and ethical issues

Dolly is a sheep.She was the first mammal to be cloned from an adult cell in 1993 Scotland.She died young from artheritis and lung disease in 2003 .Some people believe this as due to the fact that she aged quicker than normal sheep because she was a clone. 

Against:some people think cloning is wrong and (currently illegal however there is talks about plans in Russia and North Korea).

  •  it could lead to designer babies being produced as a genetic match to an older child.
  • If the child is sick the baby could be a source stem cells to treat the disease or illness.The baby is not hurt but some people think this is morally wrong to produce the science which makes this procedure possible.
  • For some people the idea of using a brain-dead clone as a organ factory for transplations is morally wrong-respect for human life more important.
  • We could produce clones of genetically modified animals(cows that produce milk with human insulin.some people argue that this would open up the opportunity to genetically modify humans and would their children be also genetically modified.

For:healthy cells from sick person cloned to repair his tissue.person could make brain dead clone of himself  as a souce of organs for transplantation.The organ will not be rejected as own genetic material.

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