Recap - just write the numbers Task 1 – put these in order

1) tRNA enters the ribosome bringing amino acids

2) mRNA is transcribed from the DNA template

3) Ribosomes attach to the mRNA strand

4) The DNA double helix untwists

5) RNA polymerase at aches to the DNA

6) As translation occurs a polypeptide is produced

7) mRNA migrates out of the nucleus

8) The polypeptide folds into a protein & is released

Answers - not on a post card

• 4 – 5 – 2 – 7 – 3 – 1 – 6 – 8• The DNA double helix untwists, RNA

polymerase at aches to the DNA, mRNA is transcribed from the DNA template, mRNA migrates out of the nucleus, Ribosomes attach to the mRNA strand, tRNA enters the ribosome bringing amino acids, As translation occurs a polypeptide is produced, The polypeptide folds into a protein & is released.

Using Microbes

C Know some microbes used in food production

C Fermenters are used to cultivate microbes

B DNA can be transferred into microbes

B Explain how insulin is mass produced

A Evaluate the use of microbes for food

A Explain the reasons why specific factors are controlled in a fermenter

What can micro-organisms possibly be useful for?

Microbes

Making GM Insulin

What’s insulin? Where’s it made? What’s its job?

• Locate and remove the human insulin gene

• Transfer the gene into Escherichia coli

• Cultivate the bacteria in a fermenter

• Harvest and purify the insulin produced

Other uses of microbes

• Spirulina

• Quorn from mycoprotein

• Bio ethanol

• Yoghurt

• Cheese

• Antibiotics

Microbes in food - QuornQuorn is Mycoprotein produced by growing fungus in a fermenter. It is very healthy because it is very low in fat so helps those with heart problems and those on calorie controlled diets.

Mycoprotein produced by the fungal microbe is protein. Mycoprotein is made from the mycelium (sorts of roots) of the fungus. The fungus is grown in huge fermenters about 40 meters tall.The fermenter is sterilised between batches using steam to ensure all contamination is removed and no other microbes are able to grow and spoil the mycoprotein that is harvested. The nutrient supply that is added glucose of energy and minerals which are also needed for the mycelium to be grown and the air supply is sent through a filter to stop any other microbes entering the fermenter. The air and ammonia gas pumped into the fermenter also acts to stir the mixture, as the bubbles float to the surface the liquid is drawn upwards. The ammonia provides nitrogen for growth. The waste gas is carbon dioxide, produced from the fungus as they use the glucose for energy. The carbon dioxide is removed at the top of the fermenter. The fermentation process takes six weeks. The temperature is kept between 35 and 38°C, the pH and oxygen supply are also closely controlled. The mycoprotein is harvested and put through a heat treatment process at 65 Celsius. The solid is then dried and pressed, cut, coloured and sometimes flavoured.The fungus requires 5 main nutrients and substances for growth, what are they?

Growing microbes in fermenters

• Types of fermenter

• Variables to control

• What might be the impact if they were not?

• 9

Growing microbes in fermenters

• Types of fermenter – gas or mechanical stirring

• Variables to control– pH, temp, sterility, nutrients, waste gasses and

chemicals, product level, oxygen, movement,

• What might be the impact if they were’nt controlled?

What are the advantages of microbes as food?

What are the advantages of microbes as food?

• Small amounts of land use

• Can be produced anywhere – control

• Simple management

• Almost continuous production

• Can use waste from other processes as food

What are the disadvantages of microbes as food?

•They do not taste very nice!

Apart from Quorn none have been successful for humans, many used as animal feed.

Home work

• Complete the Quorn sheet and find out how to make cheese.

• The main point in this and the part I’m really interested in is the microbes that are used and how they are used. Several types of cheese might need to be researched. Please present as a brief table or series of bullet points.