Because bacteria are so small, we use measurements called MICRONS to measure them.

1 mm = 1000microns

Bacteria are much smaller than animal cells.

The normal control of bacterial activity depends on its chromosomal material

Bacteria

Bacteria

Single Bacterium

circular chromosomegeneplasmid

cytoplasmA bacterium has one chromosome in the form of a complete circle and one or more plasmids.

The chromosome and plasmid are made up of genes, each of which contains the instructions to make a certain protein.

Genetic engineering can alter an organisms chromosomes by;

1. Adding new genes (often from a different organism)

2. Removing undesirable genes (eg. Those that may cause disease)

3. Increase the number of copies of a desirable gene already in the organism.

Genetic engineering

Genetic Engineering Genetic Engineering is very important to

biotechnology. It directs microbes to make products they would not normally make.

Pieces of chromosomes (genes) can be transferred from a different organism into bacteria and so allow bacteria to make new substances useful to humans, such as

Insulin (control blood sugar),

Human Growth Hormone (encourage growth in abnormally small children), and

Factor VIII (required for blood clotting).

Genetic Engineering

Genetic engineering using living cells involves many specialised techniques.

These techniques produce bacteria with altered plasmids.

The plasmids can multiply and instruct the cells to make products useful to humans.

When many such bacteria are grown together, large amounts of useful products can be obtained rapidly.

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Insulin Production

Insulin is a “chemical messenger” (hormone) produced in the pancreas.

It keeps the blood sugar at the correct level.

Some people cannot produce insulin and suffer from the disease diabetes.

A functioning human insulin gene can be removed from a non-diabetic and incorporated into the plasmid of a bacterium, which is then able to produce human insulin.

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1.Chromosome extracted and insulin gene identified

2. Gene cut out

3. Plasmid extracted

4.Plasmid cut open5. Gene inserted into plasmid

6. Plasmid inserted into bacterial host cell

7. Bacterium grows and multiplies

8. Insulin mass produced by duplicates of plasmid

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Insulin

The increase in world numbers of people suffering from diabetes, and also the fact that diabetics are living much longer, has increased the demand for insulin.

Animal insulin could therefore be in short supply, whereas genetically engineered insulin can be produced in any quantity required to meet the needs of diabetics.

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Insulin

Cattle and pig insulin are different in structure from human insulin and in some diabetics can bring about an allergic response. This may have long-term side effects such as eye and liver damage.

Genetically engineered insulin has almost exactly the same structure as human insulin and therefore allergic responses are less likely to occur.

Some diabetics do not like injecting themselves with insulin that comes from animals and prefer the ‘human’ insulin produced by bacteria.

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Other Important Products

Other important products of genetic engineering are antibiotics and vaccines.

Antibiotics are chemicals that can kill certain microbes.

Vaccines are used to prevent disease.

Thanks to genetic engineering, both can be produced more easily, quickly and in much larger quantities that before.

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Cloning

Genetic engineering may be used to alter chromosomal

material in an animal egg.

This involves inserting the required gene into a suitable egg which, when fertilised, develops with altered characteristics.

When the whole nucleus of an egg is removed and replaced with the nucleus of a normal body cell from another animal of the same type we call it cloning eg. Dolly the sheep.

Unfortunately there can be problems as the genes used are ‘old’ – dolly developed arthritis at an early age.

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CloningHow to clone a sheep

Collect a cell from a sheep (A) Collect an unfertilized egg from a sheep (B) and remove the egg’s DNA

Cell with DNA

Egg without DNA

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Genetic Engineering Verses Selective Breeding

Comparison Genetic Engineering

Selective Breeding

Time taken to improve genotype of animal or plant

Immediate Many years

Improved or completely new genotype

Possibly completely new genotype

Improved genotype

Direct or indirect alteration of genotype

Direct manipulation of chromosomes

Indirect – results are ‘hit or miss’

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Genetic Engineering and Potential Hazards

There are risks involved in reprogramming microbes.

In altering a cell’s instructions a new form of life may be created.

New strains of bacteria created by genetic engineering could be harmful to animal and plant life.

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Detergents

Biological Detergents In the past, one way to remove stains was

to boil the fabric in water with a detergent.

Many modern man-made fabrics however, are damaged by high temperatures.

Also the heat energy used is expensive.

Some detergents are called “Biological” and offer a solution to these problems.

Biological detergents contain enzymes produced by bacteria

Biological DetergentsThese detergents contain enzymes such as proteases and

lipases.These enzymes help to break down stains caused by

proteins like egg, milk and blood.The stains are broken down by the enzymes into soluble

substances, which can be washed away.

Biotechnology is responsible for the manufacture of these detergents.

The enzymes are produced by bacteria and then added to the washing powder.

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Antibiotics in Action In 1928 a Scotsman called Alexander Fleming

discovered the first antibiotic – a chemical which prevents growth of some bacteria.

This substance was named penicillin and was the first known antibiotic (something which kills microbes).

Since then many other antibiotics have been discovered and used against diseases caused by bacteria.

Any one antibiotic is not effective against all bacteria.

A bacterium is sensitive to an antibiotic if its growth is prevented by the antibiotic.

A bacterium is resistant to an antibiotic if its growth is not affected.

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P

E

S

C

Plate containing bacteria

multidisc

P = penicillin

E = erythromycin

S =sulphafurazole

C= chloramphenicol

In this example, chloramphenicol has the greatest area of clearing and is therefore the best antibiotic to get rid of this infection.

MultidiscIf someone has an infection and the doctor wants to know which antibiotic would be the most effective, the hospital would culture some bacteria from the infection and use a multidisc to quickly identify the best antibiotic to use.

Area of clearing

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Antibiotics CREDIT