Chapter 21 - Biotechnology and genetic modification

Question 1

Why is bacteria useful in biotechnology?

Answer 1

Bacteria is useful in biotechnology and genetic modification due to their rapid reproduction rate and their ability to make complex molecules. There is few ethical considerations to growing them in large numbers in the laboratory and the possess plasmids which are small, circular loops of DNA which can be an ideal way of transferring DNA from one cell to another during genetic manipulation.

Question 2

How is ethanol produced and what is it used for?

Answer 2

Yeast respires anaerobically to produce ethanol and carbon dioxide. The ethanol produces is used as biofuels. Plant material is used as the substrate for producing ethanol as it is chopped up into small pieces and mixed with yeast which respires anaerobically and produces ethanol

Question 3

How is carbon dioxide produced and what is it used for?

Answer 3

Yeast will respire anaerobically if it has access to plenty of sugar. Yeast is mixed with flour in bread making and the carbon dioxide produced is caught in the dough, causing the bread to rise.

Question 4

What is pectinase used for?

Answer 4

Pectinase is added to chopped up fruit to release more juice than normal. It works by breaking down a chemical called pectin which is found inside the plant cell walls. Once the pectin is broken down, the cell walls break more easily, and more juice can be squeezed out of the fruit. It also produces a clearer juice.

Question 5

What are biological washing powders used for?

Answer 5

Biological washing powders contain enzymes similar to digestive enzymes to quickly break down large, insoluble molecules such as fat and protein stains into smaller soluble ones that will dissolve in the washing machine. They are also effective at lower temperatures meaning less money and energy has to be used to wash clothes. They can also be used to clean delicate fabrics that would not be suitable for washing at high temperatures.

Question 6

How can milk become lactose free?

Answer 6

Milk can be made lactose free by adding the enzyme lactase to it and leaving it to stand for a while to allow the enzyme to break down the lactose.

Question 7

What is mycoprotein used for?

Answer 7

Mycoprotein is done by growing the fusarium fungus on an industrial scale in fermenters, these fermenters have large vats that can be kept at the optimum pH and temperature for the fusarium fungus to grow. The fungus will grow in aerobic conditions and provided with glucose syrup as a food source. The fungus grows and multiplies within the fermenter. The fungal biomass is then harvested and purified to produced mycoprotein.

Question 8

What conditions are controlled in a fermenter?

Answer 8

Aseptic precautions, nutrients, optimum temperature, optimum pH, oxygenation, agitation, waste

Question 9

Why and how is aseptic precautions controlled in a fermenter?

Answer 9

Fermenter is cleaned by steam to kill microorganisms and prevent chemical contamination, which ensures only the desired microorganisms can grow.

Question 10

Why and how is nutrients controlled in a fermenter?

Answer 10

Nutrients are needed for use in respiration to release energy for growth and reproduction of the microorganisms.

Question 11

Why and how is optimum temperature controlled in a fermenter?

Answer 11

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.

Question 12

Why and how is optimum pH controlled in a fermenter?

Answer 12

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.

Question 13

Why and how is oxygenation controlled in a fermenter?

Answer 13

Oxygen is required for aerobic respiration to take place.

Question 14

Why and how is agitation controlled in a fermenter?

Answer 14

Stirring paddles are used to ensure temperature, pH, nutrients, and oxygen are all distributed evenly throughout the fermenter.

Question 15

Why and how is waste controlled in a fermenter?

Answer 15

The contents are filtered to remove waste created by the microorganisms.

Question 16

How can insulin be used to treat diabetes?

Answer 16

The human gene for insulin can be inserted into bacteria through genetic modification which then produce human insulin which can be collected and purified for medical use to treat people with diabetes.

Question 17

What is genetic modification?

Answer 17

Genetic modification is changing the genetic material of an organism by removing, changing, or inserting the individual genes.

Question 18

What is the process of genetic modification using bacterial production of a human gene?

Answer 18

1. Isolation of the DNA making up a human gene using restriction enzymes to form sticky ends.
2. Cutting of bacterial plasmid DNA with the same restriction enzymes, forming complementary sticky ends.
3. Insertion of human DNA into bacterial plasmid DNA using DNA ligase to form a recombinant plasmid.
4. Insertion of recombinant plasmids into bacteria.
5. Multiplication of bacteria containing recombinant plasmids.
6. Expression in bacteria of the human gene to make the human protein.

Question 19

What are some examples of genetic modification?

Answer 19

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 diabetes.
Crop plants have been genetically modified to contain a gene from a bacteria that produces a poison that kills insects, making them resistant to insect pests.
Crop plants have another been genetically modified to make them resistant to certain herbicides meaning that when the herbicide is sprayed on the crop, it only kills weeds and does not affect the crop plant.
Some crops have been genetically modified to produce additional vitamins and improve nutritional qualities.

Question 20

What are the advantages of genetically modifying crops?

Answer 20

Reduced use of chemicals such as herbicides and pesticides are better for the environment. E.g. cheaper and less time consuming for farmers.
Increased yields from the crops as they are not competing with weeds for resources or suffering from pest damage.

Question 21

What are the disadvantages of genetically modifying crops?

Answer 21

Increased costs of seeds. Companies that make genetically modified seeds charge more for them to cover the cost of developing them, this can mean smaller and poorer farmers cannot compete with larger farms.
Increased dependency on certain chemicals such as herbicides that crops are resistant to. These are often made by the same companies that produce the seed and more expensive to buy.
Risk of inserted genes being transferred to wind plants by pollination which could reduce the usefulness of the genetically modified crop,
Reduced biodiversity as there are fewer plant species when herbicides have been used. This can impact insects and insect-eating birds.
Some research has shown that plants that have had genes inserted into them do not grow as well as non-genetically modified plants.