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33 Cards in this Set

  • Front
  • Back

What is biotechnology?

Biotechnology is the industrial use of living organisms to produce food, drugs and other products.

The living organisms used for biotechnology are mostly...

...microorganisms.

Why are microorganisms mostly used in biotechnology?

  • Their ideal growth conditions can easily be created - microorganisms will generally grow successfully as long as they have the right nutrients, temperature, pH, moisture levels and availability of gases (e.g. some oxygen).
  • Due to their short life-cycle, they grow rapidly under the right conditions, so products can be made quickly.
  • They can be grown on a range of inexpensive materials - making them economical to use.
  • They can be grown at any time of the year.

State 7 industrial processes that use microorganisms.

  • Brewing
  • Baking
  • Cheese making
  • Yogurt production
  • Penicillin production
  • Insulin production
  • Bioremediation

Explain the role of microorganisms in brewing.

  • To make beer, yeast (e.g. Saccharomyces cerevisiae) is added to a type of grain (such as barley) and other ingredients.
  • The yeast respires anaerobically using the glucose from the grain and produces ethanol (alcohol) and CO2.
  • When anaerobic respiration produces ethanol, it is called fermentation.

Explain the role of microorganism in baking.

  • Yeast makes bread rise.
  • The CO2 produced by fermentation of sugars in the dough so it does not stay flat.
  • Many flatbreads, like tortillas, are made without yeast.

Explain the role of microorganisms in cheese making (mention enzymes used, lactic acid and blue cheese).

  • Cheese production relies on a substance called rennet.
  • Rennet contains the enzyme chymosin, which clots the milk - a key process in cheese making.
  • Previously, rennet was harvested from calves stomach, but now we use bacteria that have been genetically modified to produce the enzyme.
  • Cheese making also involves lactic acid bacteria (e.g. Lactobacillus and Streptococcus). These bacteria convert lactose into lactic acid, turning it sour and aiding the solidifying process.
  • The production of blue cheeses also involves the addition of fungi to make the characteristic blue veins.

Explain the role of microorganisms in yoghurt production.

  • Yoghurt involves the use of lactic acid bacteria to clot the milk and cause it to thicken.
  • This creates a basic yoghurt and then flavours and colours are added.

Explain the role of microorganisms in penicillin production.

  • In times of stress, the fungi from the Penicillium genus produce an antibiotic, penicillin, to stop bacteria from growing and competing for resources.
  • Penicillin is one of the most common antibiotics used in medicine, so we produce it on a massive scale.
  • Penicillium Chrysogenum is grown under stress in industrial fermenters and the penicillin produced in collected and processed.

Explain the role of microorganisms in insulin production.

  • Insulin is a hormone that is crucial for treating people with type 1 diabetes.
  • Insulin is made by genetically modified bacteria, which have the gene for human insulin production inserted into their DNA.
  • These bacteria are grown in an industrial fermenter on a massive scale and the insulin produced is collected and purified.

Explain what bioremediation is and how microorganisms help carry it out.

  • Bioremediation is the process of using organisms (mostly microorganisms) to remove pollutants (e.g. oil and pesticides from contaminated sites).
  • Most commonly, pollutant-removing bacteria that occur naturally at a site are provided with extra nutrients and enhanced growing conditions to allow them to thrive.
  • These bacteria break down the pollutants into less harmful products, cleaning up an area.
  • An example of bioremediation being useful is cleaning up oil spills at sea.

Microorganisms can also be grown as a source of .........., called .......-......... .........., which act as a valuable food source for humans and other animals.

1. protein


2. single-celled proteins.

Name two examples of microorganisms used to make single-celled proteins.

  • A fungus - Fusarium venenatum (used to make Quorn).
  • A bacterium - Methylophilus methylotrophus

State four advantages of using microorganisms to produce food for human consumption.

  • Microorganisms used to make single-cell protein can be grown using many different organic substances, including waste materials such as molasses (a by-product of sugar processing). This could also be used as a way to get rid of waste products.
  • Microorganisms can be grown quickly, easily and cheaply. Production costs are low because microorganisms have simple growth requirements, they can be grown on waste products. Also, less land is required in comparison to growing crops.
  • Microorganisms can be cultured anywhere if you have the right equipment. This means that a food source could be readily produced in areas where growing food may be hard (e.g. due to very hot or cold climate). This could help tackle malnutrition in developing countries.
  • Single-cell protein is often considered a healthier alternative to animal protein.

State four disadvantages of using microorganisms to produce food for human consumption.

  • As the conditions to grow the desired microorganisms are also ideal for other microorganisms, a lot of effort has to go into making sure the food does not get contaminated with unwanted microorganisms (e.g. bacteria), which could be dangerous.
  • People may not like the idea of their food being grown using waste products.
  • Single-celled protein doesn't have the same texture of flavour as real meat.
  • If single-celled protein is consumed in high quantities, it could cause health problems due to high levels of uric acid produced when large amounts of amino acids are broken down.

Biotechnology uses cultures of microorganisms. What is a culture?

A culture is a population of one type of microorganism that's been grown under controlled conditions.

Cultures are grown in .......... containers called .......... vessels to either obtain lots of the .......... or to collect lots of a useful .......... that the microorganism makes.

1. large


2. fermentation


3. microorganism


4. product

State two of the main methods for culturing microorganisms.

  • Batch fermentation
  • Continuous fermentation
Explain what batch fermentation is.

Batch fermentation is where microorganisms are grown in individual batches in a fermentation vessel - when one culture ends it's removed and then a different batch of microorganisms are grown in the vessel. This is known as a closed culture.

Explain what continuous fermentation is.

This is where microorganisms are continually grown in a fermentation vessel without stopping. Nutrients are put in and waste products are taken out at a constant rate.

State five factors in a fermentation vessel that need to be kept at the optimum for growth.

  • pH
  • Temperature
  • Access to nutrients
  • Volume of oxygen
  • Vessel kept sterile

How is pH regulated and how does it maximise yield in a fermentation vessel?


  • Regulation - Constantly monitored by a pH probe and kept at the optimum level.
  • How it maximises yield - Allows enzymes to work efficiently, so the rate of reaction is kept as high as possible.

How is temperature regulated and how does it maximise yield in a fermentation vessel?

  • Regulation - Kept constant by a water jacket that surrounds the entire vessel.
  • How it maximises yield - Allows enzymes to work efficiently, so the rate of reaction is kept as high as possible.

How is access to nutrients regulated and how does it maximise yield in a fermentation vessel?

  • Regulation - Paddles constantly circulate fresh nutrient medium around the vessel.
  • How it maximises yield - Ensures microorganisms always have access to their required nutrients.

How is the volume of oxygen regulated and how does it maximise yield in a fermentation vessel?

  • Regulation - Sterile air is pumped into the vessel when needed.
  • How it maximises yield - Makes sure microorganisms always have enough oxygen for respiration.

How is the vessel being kept sterile regulated and how does it maximise yield in a fermentation vessel?

  • Regulation - superheated steam sterilises the vessel after each use.
  • How it maximises yield - Kills any unwanted organisms that may compete with the ones being cultured.
Label this diagram.

Label this diagram.

What is a closed culture?

A closed culture is when growth takes place in a vessel that is isolated from the external environment - extra nutrients aren't added and waste products aren't removed from the vessel during growth.

In a closed culture, a population of microorganisms follow a standard growth curve. Sketch how this graph may look like.

Name and explain what is happening in stage 1 of this graph.

Name and explain what is happening in stage 1 of this graph.

  • Lag phase
  • The population size increases slowly because the microorganisms have to make enzymes and other molecules before they produce.
  • This means the reproduction rate is slow.
Name and explain what is happening in stage 2 of this graph.

Name and explain what is happening in stage 2 of this graph.

  • Exponential phase
  • The population size increases quickly as the culture conditions are at their most favourable for reproduction (lots of food and little competition).
  • The number of microorganisms doubles at regular intervals.
Name and explain what is happening in stage 3 of this graph.

Name and explain what is happening in stage 3 of this graph.

  • Stationary phase
  • The population size stays level as the death rate of the microorganisms equals their reproductive rate.
  • Microorganisms die as there is not enough food and poisonous waste products build up.
Name and explain what is happening in stage 4 of this graph.

Name and explain what is happening in stage 4 of this graph.

  • Decline phase
  • The population size falls because the death rate is greater than the reproductive rate.
  • This is because food is very scarce and waste products are at toxic levels.