Biotechnology Cambridge IGCSE Biology revision
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In plain words
Long before anyone knew what a microbe was, people were using them to make bread and beer. Today bacteria and yeast are tiny factories, making everything from fuel to the enzymes in washing powder.
Three things to know
- Bacteria are useful in biotechnology because they reproduce very fast and can make complex molecules. They also have plasmids, small rings of DNA that are easy to change.
- Yeast respires anaerobically to make ethanol (for biofuel) and carbon dioxide (which makes bread rise). Pectinase helps to get more juice out of fruit and makes it clear. Biological washing powders contain enzymes that digest stains.
- Lactase is used to make lactose-free milk. Fermenters are used to grow microorganisms on a large scale to make insulin, penicillin and mycoprotein, with temperature, pH, oxygen and nutrients all controlled.
Tips and tricks
- Biological washing powders work at low temperatures. In a very hot wash the enzymes are denatured.
- Match the enzyme to the job: pectinase for juice, lactase for milk, proteases and lipases for stains.
It lands in your notebook with its questions as flashcards.
Biotechnology: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
Why are bacteria useful in biotechnology?
A few bacteria soon become billions.
Which enzyme is used to make fruit juice?
It breaks down pectin, releasing more juice.
What does yeast produce that is used as a biofuel?
It is made by anaerobic respiration.
What is lactase used for?
It breaks down lactose, the sugar in milk.
Why should biological washing powder not be used in a very hot wash?
Their active sites change shape.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 6 marks. Write your answers on paper, then check them.
Biotechnology
Cambridge IGCSE Biology 0610 · 6 marks · papermunch.org
Name ______________________________ Date ______________
Give two reasons why bacteria are useful in biotechnology.[2]
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They reproduce rapidly, and they can make complex molecules. (They also have plasmids, and there are few ethical concerns about using them.)
Explain how biological washing powders remove stains such as egg and grease.[2]
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They contain enzymes: proteases break down the protein in egg, and lipases break down the fat in grease, into smaller soluble molecules that wash away.
State why pectinase is used in making fruit juice.[2]
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It breaks down pectin in the cell walls of the fruit, so more juice is released and the juice is clearer.
Answers: Biotechnology
- 1. They reproduce rapidly, and they can make complex molecules. (They also have plasmids, and there are few ethical concerns about using them.)
- 2. They contain enzymes: proteases break down the protein in egg, and lipases break down the fat in grease, into smaller soluble molecules that wash away.
- 3. It breaks down pectin in the cell walls of the fruit, so more juice is released and the juice is clearer.