6.2.1 Biotechnology

Question 1

Define biotechnology

Answer 1

Industrial use of living organisms to produice drugs and food

Question 2

List uses of biotechnology (5)

Answer 2

• Food production
• Drug production
• Enzyme production
• Chemical production
• Bioremediation of waste

Question 3

Why are microorganisms used in biotechnology? (6)

Answer 3

• Fast growth rate
• Can be genetically engineered
• Often occur at low temperatures + pressures - cheaper + safer to maintain
• Produces pure products
• Products easy to seperate
• Grow on unwanted food/nutrients

Question 4

What is indirect food production?

Answer 4

When microorganisms have an indirect effect - we eat the byproduct of te microorganism

Question 5

What is direct food production?

Answer 5

When the microorganism is eaten e.g. SCP (Quorn)

Question 6

Advantages of using microrganisms in food production (7)

Answer 6

• Faster growth rate than animals
• Production can be altered according to demand
• No animal welfare issues
• Source of protein for vegetarians/vegans
• Contains no saturated fat or cholesterol
• Less land and energy used than conventional agriculture
• Microbes have simple food requirments and can grow on waste

Question 7

Disadvantages of using microorganisms in food production (5)

Answer 7

• People may not want to eat fungal protein
• Microorganisms need to be isolated from protein product
• Protein needs to be purified to prevent contamination
• Care needs to be taken to prevent pathogenic organisms growing
• Protein doesn’t have the same texture or taste of traditional protein

Question 8

Explain the requirements to produce Penicillin

Answer 8

• Semi continous batch fermentation
• Small fermenters to maintain high oxygen levels
• Mixture continuously stirred to keep it oxygenated
• Rich nutrient medium with pH 6.5 buffer
• 25-27 degrees temp maintained

Question 9

How was insulin produced in the past and disadvantages of this?

Answer 9

Insulin produced from pancreas of pigs or cattle
- Erratic supply
- Some allergic to animal insulin
- Religous objections

Question 10

What is bioremediation?

Answer 10

Microorganisms used to break down pollutants in soil + water

Question 11

How are microrganisms used in healthcare?

Answer 11

Drug production e.g. insulin by genetically modified bacteria
Antibiotics e.g. penicillin produced by fungus

Question 12

How are microorganisms used in agriculture?

Answer 12

Genetically modified plants e.g. golden rice
Micropropagation of plants

Question 13

How are microorganisms used in industry?

Answer 13

Water treatment - bacteria remove organic waste from water
Bio gas fuel - Bacteria convert sewage into methane

Question 14

How are microorganisms used in food science?

Answer 14

Production of cheese and yoghurt
Mycoprotein (Quorn) is a fungus
Brewing + baking use yeast

Question 15

What is a closed culture?

Answer 15

When no new materials are added and no waste products are removed

Question 16

What are the limiting factors of microorganism growth (5)

Answer 16

• Nutrients
• Oxygen
• Temperature
• Build up of waste
• pH change

Question 17

What is fermentation?

Answer 17

Te use of anaerobic respiration to make ethanol from yeast
(Now includes culturing of microrganisms both anaerobically + aerobically)

Question 18

What are metabolites?

Answer 18

Products made by microorganisms through metabolism

Question 19

What are primary metabolites?

Answer 19

Molecules created by organisms required for normal survival and grwoth e.g. proteins, enzymes

Question 20

Describe and explain the production of primary metabolites in comparison to the growth of a population

Answer 20

Same shape as the population growth curve as primary metabolites requiredd for survival
Production increases as population increases
Producion lags just slightly behind growth curve
Produced in all growth phases

Question 21

What are secondary metabolites?

Answer 21

Products created by organisms that are not required for growth
e.g. Antibiotic penicillin

Question 22

Describe and explain the production of secondary metabolites in comparison to the growth of a population

Answer 22

Some production in log phases, however most after log phase
Production normally occurs when nutrients have become depleted (e.g. releasing antiboitics to reduce competition)
Does not stick to population growth curve
Not many microorganisms produce secondary metabolites

Question 23

Name parts of a fermenter and their purpose (6)

Answer 23

Air inlet: Provides oxygen for aerobic fermenters
Impellers: Mixes microbes with substrate
Water jacket: Regulates temperature
Nutrient inlet: Provides nutrients for microorganisms
Electronic probes: Measures oxygen, Ph, temperature
Outlet tap: Used for draining fermenter

Question 24

What conditions are controlled within a fermenter and why? (4)

Answer 24

Temperature
- Too hot: Denatures proteins
- Too cold: Decreases growth rate

Type + Time of Nutruent Addition
- Carbon, nitrogen, vitamins, minerals added
- Timing of addition of nutreients manipulated depending on if primary or secondary metabolites are desired

Oxygen Concentration
- Many processes rely on aerobic respiration for grwoth
- If oxygen not provided, grwoth decreaes + unwanted productsfrom anaerobic respiration may be created

pH
- Too low or too high: Denaturing of proteins
- Controlled with buffers to maintain pH at a set point

Question 25

What is a batch culture?

Answer 25

Where a starter population of microorganism is mixed with a fixed amount of nutrients. No more is added and all products removed at the end. E.g. Penicillin

Question 26

What is a continous culture?

Answer 26

Where a sarte population of microorganism is mixed with nutrients added continously and products removed continously. Can go on for weeks, months or years. E.g. Insulin from GM bacteria

Question 27

Advantages and disadvantages of batch culture (3+2)

Answer 27

**Advantages** - Easy to set up and maintain - Useful for processes creating secondary metabolites - If contamination occurs only one batch is lost **Disadvantages** - Slower growth rate as nutrient level declines over time - Fermeneter is not in use all the time, so less efficient

Question 28

Advantages and disadvantages of batch culture

Answer 28

**Advantages** - Faster grwoth rate as nutrients added continuously - Fermenter operates continuously so more efficient - Useful for processes creating primary metabolites **Disadvantages** - Setup is more difficult and requires continous maintenance - Large volumes may be lost if contamination occurs

Question 29

Define a culture

Answer 29

A growth of microorganisms either pure (one species) or mixed (different species) in liquid nutrient broth or on solid agar gel

Question 30

Why is health and safety needed when culturing microorganisms?

Answer 30

- Ther is risk of mutation making pathogenic strains - May becomes contaminated from pathogenic microorganisms from the environment

Question 31

Describe the process of creating an inoculating broth (5)

Answer 31

1. Make a suspension of bacteria to be grown 2. Mix with sterile nutrient broth in the flask 3. Stopper with cotton wool 4. Incubate at appropriate temperature 5. Shake regularly

Question 32

Describe how to use inoculating agar (4)

Answer 32

1. Wire inoculating loop sterilised by holding to bunsen flame 2. Sterilised loop put in bacterial suspension 3. Remove lid of petri dish and make a zig-zag streak accross the surface of the agar 4. Replace lid

Question 33

Define asepsis

Answer 33

The absence of unwanted microorganisms

Question 34

Define contaminants

Answer 34

Unwanted, contaminating miroorganisms

Question 35

Why must contaminants be excluded? (4)

Answer 35

- They compete with microbes for nutrients and space - They cause reduction in yield of useful products - They contaminate + spoil the final product - They may produce toxic chemicals

Question 36

Define aseptic technique

Answer 36

Steps taken to prevent contamination by unwanted microbes or products

Question 37

Describe aspectic techniques in the lab (4)

Answer 37

- Steam sterilise equipment in an autoclave at 121 degrees for 15 minutes - Expose equipment to UV liht - Use fume cupboards to prevent airborne contamination - Work around a bunsen flame - flame neck of glass bottles, spreaders

Question 38

Describe aseptic techniques in large scale cultures (4)

Answer 38

- Wash, disinfect and steam clean fermenters when not in use - Surfaces made from stainless steel to prevent microbes sticking to it - Fine filters on inlet + outlet pipes to prevent microbes entering - Nutrient mediums sterelised before being added

Question 39

Why are enzmes used in industrial production? (3)

Answer 39

- Enzymes are specific in their reactions so can be used in mixtures of many chemicals - fewer byproducts so less purification requried - Can lower temperature for a reaction so save money on fuel costs - Some enzymes can function at very high or low temperatures

Question 40

Why are free enzymes used not whole organisms? (3)

Answer 40

- Less wasteful (Whole organism not using substrate for growth+ reproduction) - More efficient - can use exact amount of enzyme required for optimum conditions - More specific - no unwanted enzymes used or unwanted reactions

Question 41

What are immobilised enzymes?

Answer 41

Technique where enzymes are held separate from substrate. Substrates can bind to enzyme but products return to the mixture Enzymes bond to an insoluble material

Question 42

Describe surface immobilisation via adsorption and give advantages and disadvantages

Answer 42

Enzyme molecules mixed with adsorbing agents (glass/clay/carbon) - Enzymes bond to solid via hydrophobic interactions - Simple, cheap and enzyme activity unchanged - Enzymes can deattach due to weak bonds

Question 43

Describe surface immobilisation via covalent or ionic bonds and give advantages and disadvantages

Answer 43

Enzyme bonded to solid by covalent or ionic bonds - Enzymes unlikely to be lost and are unaffected by pH and substrate cconcentration - Cost varies + sometimes active site modified

Question 44

Describe surface enzyme entrapment and give advantages and disadvantages

Answer 44

Enzyme trapped in a matrix (small gel bead or a network of cellulose fibers) - Not bonded to anther molecule so active site unaffected - Diffusion if substrate in + product out can be slow and hold up the reaction

Question 45

Describe membrane separation and give advantages and disadvantages

Answer 45

Enzyme separated behind a partially permeable membrane - Simple and little activity on enzyme activity - Diffusion of substrate to + product from active site can be slow and hold up the reaction

Question 46

Advantages of using immobolised enzymes

Answer 46

- Can be reused which lowers cost - Produc is pure + uncontaminated - Easily separate reactants + products (Less downstream processsing so cheaper) - Immobilised enzymes work at higher temperatures - Immobilised enzymes work in changed pH - Reactions can be faster and have higher yield as can be done at higher temperatures

Question 47

Disadvantages of using immobilised enzymes

Answer 47

- Activity of enzyme can decreases - Higher initial cost compared to free enzymes - Initial investment costly for system that uses immobilised enzymes - More technical issues to go wrong

Question 48

Examples of immobilised enzymes

Answer 48

- Glucose isomerase - fructose from glucose - Lactase - Hydrolyses lactose in milk to glucose