18.1 Biotechnology (Cambridge (CIE) O Level Biology): Flashcards
Exam code: 5090
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Define biofuel.
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Define biofuel.
A fuel made from living organisms rather than a fossil fuel such as oil, coal or gas.
Which microorganism is used to produce ethanol for use as a biofuel?
Yeast, a single-celled fungus that respires anaerobically, using sugar from plant material.
Ethanol used as a biofuel is produced when yeast respires , using plant material as a substrate.
Ethanol used as a biofuel is produced when yeast respires anaerobically, using plant material as a substrate.
Why does bread dough rise when yeast is added?
Yeast respires anaerobically and produces carbon dioxide, which is trapped in the dough and makes it rise.
Define pectinase.
An enzyme that breaks down pectin in plant cell walls, releasing more juice from fruit.
How does adding pectinase increase the yield of fruit juice?
It breaks down pectin in the cell walls, so the walls break more easily and more juice is released. It also produces a clearer juice.
What do biological washing powders contain that helps remove stains?
Enzymes that break down large, insoluble molecules such as fats and proteins into smaller, soluble ones that dissolve in the washing water.
Give one advantage of using biological washing powders.
They are effective at lower temperatures, so less energy is needed. They can also clean delicate fabrics.
Define lactase.
The enzyme that breaks down lactose, the sugar found in milk.
Milk is made lactose-free by adding the enzyme , which breaks down the lactose.
Milk is made lactose-free by adding the enzyme lactase, which breaks down the lactose.
True or False?
Biological washing powders are effective at lower temperatures.
True.
Their enzymes work at lower temperatures, so less energy and money are needed to heat the water.
True or False?
Yeast produces oxygen when it respires to make biofuel.
False.
When yeast respires anaerobically it produces ethanol and carbon dioxide, not oxygen.
Define plasmid.
A small, circular loop of DNA found in bacteria.
Which is the most common type of microorganism used in biotechnology?
Bacteria.
Give two reasons why bacteria are useful in biotechnology.
Any two of:
reproduce rapidly
produce complex molecules
few ethical concerns
possess plasmids
Bacteria are useful in biotechnology because they reproduce , so the amount of chemicals they make can quickly increase.
Bacteria are useful in biotechnology because they reproduce rapidly, so the amount of chemicals they make can quickly increase.
How do bacteria help to produce yoghurt?
Certain bacteria added to milk produce enzymes that turn the milk into yoghurt.
What can microorganisms be used to produce for humans?
Foods and other useful substances.
Plasmids are an ideal way of transferring from one cell to another during genetic manipulation.
Plasmids are an ideal way of transferring DNA from one cell to another during genetic manipulation.
Why does the ability of bacteria to make complex molecules make them useful?
They can produce useful substances that would otherwise be hard to make, such as the enzymes that turn milk into yoghurt.
True or False?
There are few ethical concerns about growing bacteria in large numbers.
True.
Unlike animals, bacteria raise few ethical concerns, so they can be grown in large numbers in the laboratory.
True or False?
Plasmids are circular loops of DNA.
True.
Plasmids are small, circular loops of DNA found in bacteria.
Bacteria are capable of producing molecules, such as the enzymes used to make yoghurt.
Bacteria are capable of producing complex molecules, such as the enzymes used to make yoghurt.
Define fermenter.
A container used to grow (culture) microorganisms such as bacteria and fungi in large amounts.
Who discovered penicillin, and in which year?
Alexander Fleming, in 1928.
Which organism produces penicillin?
The mould Penicillium, which makes a chemical that prevents infection by certain bacteria.
Penicillin was the first to be discovered.
Penicillin was the first antibiotic to be discovered.
What is the main advantage of using a fermenter to grow microorganisms?
Conditions can be carefully controlled to produce large quantities of exactly the right type of microorganism.
Why is temperature controlled in a fermenter?
To keep the optimum temperature for enzymes, increasing enzyme activity and preventing denaturation. It is maintained using a water jacket.
Why are aseptic precautions used in a fermenter?
The fermenter is cleaned with steam to kill microorganisms and prevent contamination, so only the desired microorganisms grow.
What is the purpose of the stirring paddles (agitation) in a fermenter?
To distribute temperature, pH, nutrients and oxygen evenly throughout the fermenter.
Oxygen is supplied in a fermenter so that the microorganisms can carry out respiration.
Oxygen is supplied in a fermenter so that the microorganisms can carry out aerobic respiration.
Define mycoprotein.
A protein-rich food made from the fungus Fusarium, suitable for vegetarians (e.g. used in Quorn products).
How is mycoprotein produced in a fermenter?
The fungus Fusarium is grown in aerobic conditions with glucose syrup as food; the biomass is then harvested and purified.
True or False?
A fermenter allows conditions such as temperature and pH to be carefully controlled.
True.
Controlling the conditions ensures large quantities of the desired microorganism can be grown.
True or False?
Bacteria grown in a fermenter can be genetically modified to produce human insulin.
True.
Genetically modified bacteria are grown in a fermenter to make large quantities of human insulin to treat diabetes.
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