Biotechnology & Genetic Modification (Cambridge (CIE) IGCSE Biology)
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Define the term biotechnology.
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Define the term biotechnology.
Biotechnology is the use of living organisms to produce products that are useful to humans.
Why are bacteria useful in biotechnology?
Bacteria are useful in biotechnology because:
they have a rapid reproduction rate
they can produce complex molecules
there are few ethical concerns around their use (Extended Tier Only)
they contain plasmids (Extended Tier Only)
Why does the presence of plasmids in bacteria make them useful in biotechnology. (Extended Tier Only)
Plasmids in bacteria are useful in biotechnology because they are an easy way of introducing new genes into bacteria during genetic modification.
How do yeast cells produce ethanol for biofuels?
Yeast produce ethanol for biofuels during anaerobic respiration as follows:
glucose
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ethanol + carbon dioxideTrue or False?
Yeast requires oxygen to respire.
False.
Yeast can carry out anaerobic respiration in the absence of oxygen.
What is the role of yeast in bread making?
In bread making yeast uses sugars for anaerobic respiration, producing carbon dioxide that causes the dough to rise.
True or False?
Pectinase enzyme is involved in the production of cloudy fruit juices.
False.
Pectinase enzyme enables the production of clear fruit juices.
What is the benefit of adding enzymes to washing powders?
It is useful to add enzymes to washing powders because:
the enzymes can break down biological stains containing fats and proteins
enzyme operate effectively at lower temperatures, so washing temperatures can be reduced
How can enzymes be used in the production of lactose-free milk? (Extended Tier Only)
Lactose free milk can be produced using lactase enzymes which break down the lactose in milk.
What products can be produced on a large scale using industrial fermenters? (Extended Tier Only)
Products that can be produced in fermenters include:
insulin
penicillin
mycoprotein
What is mycoprotein?
Mycoprotein is a protein-rich food produced by a fungus. It is suitable for vegetarians and often used as a meat-substitute.
Which conditions need to be controlled inside a fermenter? (Extended Tier Only)
Conditions that need to be controlled inside a fermenter include:
temperature
pH
oxygen concentration
nutrient supply
concentration of waste products
Why does temperature need to be controlled inside fermenters? (Extended Tier Only)
Temperature needs to be controlled inside fermenters because respiring microorganisms release heat when they respire. The fermenter therefore needs to be kept cool to ensure that microbial enzymes do not denature.
What is genetic modification?
Genetic modification involves changing the genetic material of an organism by removing, changing or inserting individual genes.
True or False?
Human genes can be inserted into bacteria, which then produce human proteins.
True.
Human genes can be inserted into bacteria for the production of human proteins, e.g. insulin.
Why might crop varieties be genetically modified?
Crop varieties might be genetically modified to introduce:
herbicide resistance
pest resistance
new nutritional qualities
What is the role of restriction enzymes in genetic modification? (Extended Tier Only)
Restriction enzymes are used in genetic modification to cut specific DNA sequences, allowing for the isolation of genes. These enzymes cut DNA at specific nucleotide sequences, resulting in fragments with sticky ends.
True or False?
The desired gene is isolated using the same restriction enzyme that is used to cut the plasmid during genetic modification. (Extended Tier Only)
True.
The same restriction enzyme is used to cut the human gene and the plasmid to make sure they have the same complementary DNA bases on their sticky ends; this allows the sticky ends to bond together.
What is recombinant DNA? (Extended Tier Only)
Recombinant DNA is DNA taken from two different organisms combined into one strand.
What is the role of plasmids in genetic modification? (Extended Tier Only)
Plasmids allow DNA to be transferred into bacterial cells.
How do bacteria produce more copies of the recombinant plasmids? (Extended Tier Only)
Bacteria make copies of the modified recombinant DNA inside them as they reproduce by asexual reproduction. This passes on the recombinant DNA to their offspring.
Why are genetically engineered bacteria useful in the production of specific proteins, e.g. insulin? (Extended Tier Only)
Once bacteria have been genetically modified to contain the correct gene, they are able to reproduce quickly and synthesise the specific protein required.
How has rice been genetically modified to increase its health benefits? (Extended Tier Only)
Rice has been genetically modified to produce golden rice which has an increased vitamin A content.
True or False?
Soya has been genetically modified to produce Bt toxin which kills insect pests. (Extended Tier Only)
False.
Soya has been modified to provide herbicide resistance, meaning that it can be treated with a weedkiller without harming the crop.
Bt toxin is produced by GM maize and GM cotton.
What are some advantages and disadvantages of genetic modification in crops? (Extended Tier Only)
Advantages and disadvantages of genetic modification in crops include:
Advantages
Disadvantages
Improved nutritional content of foods
Seeds are more expensive to buy
Reduction in pesticide use as crops may be pest resistant
Risk of new genes escaping into wild plant populations
Increased yield
GM crops may produce toxins that harm non-target species as well as pests