Biology Chapter 20 Biotechnology and genetic engineering

Question 1

Define Genetic Engineering

Answer 1

Changing the genetic material of an organism by removing, changing or inserting individual genes

Question 2

Why does Biotechnology and Genetic Engineering use bacteria?

Answer 2

This is due to bacteria’s ability to make complex molecules such as proteins, and their rapid reproduction rate

Question 3

Why is Bacteria useful in biotechnology and genetic engineering?

Answer 3

• lack of ethical concerns over their manipulation and growth
• genetic code shared with other organisms
• presence of plasmids

Question 4

Describe the production of ethanol by fermentation

Answer 4

Yeast breaks down glucose to ethanol through anaerobic respiration. The ethanol can be produced commercially for biofuel.

Formula:
Glucose (C6H12O6) -> ethanol (2C2H5OH) + carbon dioxide (2CO2) + energy released

Question 5

Describe the production of bread using fermentation

Answer 5

Anaerobic respiration by yeast is also involved in bread making. Holes in bread are caused by trapped carbon dioxide produced by yeast. This carbon dioxide causes the dough to rise.

Question 6

N.I.S

What are the commonest organisms used to produce enzymes in fermentation

Answer 6

Fungi (e.g. Aspergillus) or bacteria (e.g. Bacillus)

Question 7

N.I.S

The reactions that are useful in fermentation biotechnology are mostly those that ..

Answer 7

Produce incompletely oxidized compounds. A reaction that goes all the way to carbon dioxide and water is not of much use.

Question 8

N.I.S

Why are sterile conditions essential in biotechnology?

Answer 8

To avoid contamination by unwanted microbes

Question 9

Describe the use of Pectinases in fruit juice production

Answer 9

Pectinases can be extracted from fungi such as Aspergillus Niger.
During the juicing process a number of different polysaccharides are released which make the juice cloudy.
Pectinases break these down to make the juice clearer. The sugars produced also make the juice sweeter

Question 10

Investigate and describe the use of biological washing powders that contain enzymes

Answer 10

When protease and lipase are combined in washing powders, they are effective in removing stains in clothes caused by proteins and fats (blood, grease)

Question 11

Investigate and explain the use of lactate to produce lactose free milk

Answer 11

A simple way to make lactose free milk is to add lactase to milk. The enzyme breaks down lactose sugar into two monosaccharide sugars: glucose and galactose, which can be both absorbed by the intestine

Question 12

Describe the role of the fungus Penicillium in the production of the antibiotic penicillin

Answer 12

Penicillium mold naturally produces antibiotic penicillin.
Penicillium mold is grown in deep fermentation tanks by adding a kind of sugar and other ingredients. This increases growth of Penicillium.
Then the penicillin product is separated from mold.
Penicillin is purified for use in antibiotic medicine.

Question 13

Explain how fermenters are used in the production of penicillin

Answer 13

For penicillin production, the carbohydrate source is sugar, mainly lactose or corn steep liquor. It contains amino acids and sugars. Mineral salts are added, the pH is adjusted between 5 and 6, the temperature is maintained at about 26 degrees, air is blown through the liquid and stirred.
The nutrient liquid is seeded with a culture of the appropriate microorganism, which is allowed to grow for a day or two.
Sterile conditions are essential. Foreign bacteria or fungi can completely disrupt the process.
As the nutrient supply diminishes, the microorganisms begin to secrete their antibiotics into the medium.
Nutrient fluid containing the antibiotic is filtered off and antibiotic extracted by crystallization or other methods.

Question 14

Name the examples of genetic engineering

Answer 14

• the insertion of human genes into bacteria to produce human insulin
• the insertion of genes into crop plants to confer resistance to herbicides or insect pests
• the insertion of genes into crop plants to provide additional vitamins

Question 15

Outline genetic engineering using bacterial production of a human protein

Answer 15

• Isolation of the DNA making up a human gene using restriction enzymes, forming sticky ends
• cutting of bacterial plasmid DNA with the same restriction enzymes, forming complementary sticky ends
• insertion of human DNA into bacterial plasmid DNA using DNA ligase to form recombinant plasmid - insertion of plasmid into bacteria
• replication of bacteria containing recombinant plasmids which make human protein as they express the gene

Question 16

Discuss the advantages of genetically modifying crops, such as soya, maize and rice

Answer 16

• Nutritional value of foods could be improved (by introducing proteins, vitamins or vaccines)
• Crops can be produced that lack known allergens
• Crops can grow in arid conditions for better yield
• GM crops can produce herbicides to kill pests
• Improve food supply/ agriculture in poor countries (GM crops can be engineered for improved yields)
• GM crops may have longer shelf lives
• Reduces economic cost and carbon footprint -> less need for land clearing and pesticide usage

Question 17

Discuss the disadvantages of genetically modifying crops, such as soya, maize and rice

Answer 17

• New traits could cause adverse health reactions (new proteins may cause allergic responses)
• Removal of traits could have unknown effects
• Crops may limit biodiversity of local environment
• cross pollination could lead to super weeds
• Biotech companies hold monopolies over crop use
• Foods with GM components may not be labeled
• Different governments may have conflicting regulatory standards concerning safe usage

Question 18

Define plasmid

Answer 18

Circle of DNA that can carry a foreign section of DNA