Ch 21 - (Biotechnology and genetic modification) Flashcards
What is used by humans to produce foods and other substances?
Microorganisms
what is the most common type of microorganism used in biotechnology?
Bacteria
Why is bacteria useful is biotechnology?
- capable of producing complex molecules
- reproduce rapidly,
What’s re additions useful effects of using bacteria?
- There are few ethical considerations to growing them in large numbers in the laboratory
- They possess plasmids
Plasmids are small, circular loops of DNA which can be an ideal way of transferring DNA from one cell to another during genetic manipulation
What is yeast?
single celled fungus that uses sugar as its food source
What happens when yeast respires?
ethanol and carbon dioxide are produced (and energy is released)
what happens when ethanol is produced by yeast?
increasingly being used as a biofuel (a fuel made from living organisms rather than a fossil fuel like oil, coal or gas)
What is sued as the substrate for producing ethanol?
- Plant material is used for producing ethanol (as a source of glucose) - it is chopped up into small pieces and mixed with yeast which respires anaerobically and produces ethanol
What happens from the leftover liquid from ethanol?
- separated from the remaining solids and any water is removed, leaving a concentrated solution of ethanol
- waste parts of crop plants, such as the stalks or outer leaves, are used, but in other places, crops are grown specifically to be harvested for making ethanol
- causing concern that there is less land available for local people to grow food crops needed for survival
How does yeast respire in bread making?
respire anaerobically if it has access to plenty of sugar, even if oxygen is available
How is respiration of yeast in bread an advantage?
- bread making, where the yeast is mixed with flour and water and respires anaerobically, producing carbon dioxide:
- Carbon dioxide produced by the yeast during respiration is caught in the dough, causing the bread to rise
How is fruit juice produced?
- by squeezing the fruits to remove the juice
- chopping the fruit up before squeezing helps to release a lot more juice, but this does not break open all the cells, so a lot of juice is lost
- adding an enzyme called pectinase
- Pectinase works by breaking down a chemical called pectin that is found inside plant cell walls
- Once pectin is broken down, the cell walls break more easily, and more juice can be squeezed out of the fruit
- Adding pectinase to fruits also helps to produce a clearer juice as larger polysaccharides like pectin can make the juice seem cloudy - once they are broken down into smaller molecules, the juice becomes clearer
How is biological washing powders made?
- stains on clothes are organic molecules
- detergents that only contain soap can remove some of these stains when mixed with hot water, but it can take a lot of time and effort and very high temperatures
- Biological washing powders contain enzymes
What is the advantage of using biological washing powders?
- Quickly breaking down large, insoluble molecules such as fats and proteins into smaller, soluble ones that will dissolve in washing water
- They are effective at lower temperatures, meaning less energy (and money)
- They can be used to clean delicate fabrics that would not be suitable for washing at high temperatures
What is lactose?
the sugar found in milk
What are human babies born with?
the ability to produce lactase, the enzyme that breaks down lactose
What happens when people lose the ability to produce lactase as they get older?
- they can become lactose intolerant and react badly to the lactose
- Symptoms of lactose intolerance include nausea, flatulence and diarrhea
How can milk be made lactose free?
- Milk can be made lactose free by adding the enzyme lactase to it
What is penicillin?
the first antibiotic, discovered in 1928 by Alexander Fleming
What did Alexandar Fleming notice?
some bacteria he had left in a Petri dish had been killed by the naturally occurring Penicillium Mould
Mould produces a chemical to prevent it being infected by certain types of bacteria
What are fermenters?
containers used to grow (‘culture’) microorganisms like bacteria and fungi in large amounts
How are fermenters used?
biotechnological processes like producing genetically modified bacteria and the penicillium mould that produces penicillin
What are the conditions that can be carefully controlled in fermenter?
1.Aseptic precautions
2.Nutrients
3.Optimum temperature
4.Optimum pH
5.Oxygenation
6.Agitation
7.Waste
Why and how is aseptic precautions controlled in a fermenter?
Fermenter is cleaned by steam to kill microorganisms and prevent chemical contamination, which ensures only the desired microorganisms can grow
Why and how is nutrients controlled in a fermenter?
Nutrients are needed for use in respiration to release energy for growth and reproduction of the microorganisms
Why and how is optimum temp controlled in a fermenter?
Temperature is monitored using probes and maintained using a water jacket. This ensures an optimum environment for enzymes to increase enzyme activity and prevent denaturation
Why and how is optimum pH controlled in a fermenter?
pH is monitored using a probe to check it is at the optimum value for the microorganism being grown. The pH can be adjusted using acids and alkalis
Why and how is oxygenation controlled in a fermenter?
Oxygen is required for aerobic respiration to take place
Why and how is agitation controlled in a fermenter?
Stirring paddles are used to ensure temperature, pH, nutrients, and oxygen are all distributed evenly throughout the fermenter
Why and how is waste controlled in a fermenter?
The contents are filtered to remove waste created by the microorganisms
What is Fusarium?
he fungus Fusarium is cultured (grown) on an industrial scale in fermenters
How is Fusarium grown?
- aerobic conditions (it is provided with oxygen) and provided with glucose syrup as a food source (to allow the fungus to respire)
- The fungus grows and multiplies within the fermenter
- The fungal biomass is then harvested and purified to produce mycoprotein
What is mycoprotein?
Mycoprotein is a protein-rich food suitable for vegetarians
Define genetic modification
changing the genetic material of an organism by removing, changing or inserting individual genes from another organism
What is the organism receiving the genetic material called?
‘genetically modified’, or is described as a ‘transgenic organism’
What is the process of genetic modification?
‘recombinant DNA’
How is human insulin made?
The gene for human insulin has been inserted into bacteria which then produce human insulin which can be collected and purified for medical use for diabetics
How is genetic modification in crops?
- Crop plants have also been genetically modified to make them resistant to certain herbicides (chemicals that kill plants)
- produce additional vitamins, eg ‘golden rice’
Explain the genetic modification of bacteria from human protein.
Restriction enzymes are used to isolate the required gene, leaving it with ‘sticky ends’ (a short section of unpaired bases)
A bacterial plasmid is cut by the same restriction enzyme leaving it with corresponding sticky ends (plasmids are circles of DNA found inside bacterial cells)
The plasmid and the isolated gene are joined together by DNA ligase enzyme
If two pieces of DNA have matching sticky ends (because they have been cut by the same restriction enzyme), DNA ligase will link them to form a single, unbroken molecule of DNA
The genetically engineered plasmid is inserted into a bacterial cell
When the bacteria reproduce the plasmids are copied as well and so a recombinant plasmid can quickly be spread as the bacteria multiply and they will then all express the gene and make the human protein
The genetically engineered bacteria can be placed in a fermenter to reproduce quickly in controlled conditions and make large quantities of the human protein
Why is bacteria extremely useful for genetic engineering?
They contain the same genetic code as the organisms we are taking the genes from, meaning they can easily ‘read’ it and produce the same proteins
There are no ethical concerns over their manipulation and growth (unlike if animals were used, as they can feel pain and distress)
The presence of plasmids in bacteria, separate from the main bacterial chromosome, makes them easy to remove and manipulate to insert genes into them and then place back inside the bacterial cells
What are the advantages of genetically modified crops?
What are the disadvantages of genetically modified crops?
