Unit 21 - Biotechnology and genetic modification

Question 1

Biotechnology

Answer 1

The exploitation of biological processes by humans for industrial and other purposes

Question 2

Genetic engineering / Genetic modification (GM)

Answer 2

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

Question 3

How humans use bacteria

Answer 3

• Food production
• Breaking down sewage
• Production of useful chemicals
• Production of antibiotics and food supplements
• Making hormones e.g. insulin
• Conversion of wastes into fuel
• Making transgenic plants
• Cleaning oil spills

Question 4

Reasons why bacteria is useful

Answer 4

• They can reproduce rapidly
• They can make complex compounds e.g. vitamin B12 & insulin

Question 5

Role of plasmids in genetic modification

Answer 5

A gene for a protein is inserted in the plasmid and is then transferred to the genetic material of a bacterial cell which will express the gene and make the protein

Question 6

Yeast

Answer 6

A microscopic single-celled fungus

Question 7

Yeast anaerobic respiration equation / fermentation

Answer 7

C6H12O6 –> 2C3H5OH + 2CO2

Question 8

Alcohol produced by yeast

Answer 8

ethanol

Question 9

Ways to make ethanol

Answer 9

• Ethene reacting with steam at high temperatures
• Cellulose digested by enzymes mixed with yeast and water in a warm oxygen-free atmosphere

Question 10

Use of ethanol as a fuel

Answer 10

Can be used directly or mixed with petrol to make biofuel

Question 11

Use of yeast in bread

Answer 11

When oxygen is used anaerobic respiration happens and carbon dioxide causes the bread to rise whilst ethanol boils due to the oven

Question 12

Common industries that use enzymes and how

Answer 12

• Production of fruit juice - pectinate used to break down pectin (protein that holds cell walls together) to allow juice to be extracted easily
• Biological washing powders - enzymes are in washing powders to break down the substances in fabric stains

Question 13

Reason for lactose intolerance

Answer 13

A lack of lactase that is produced in the wall of intestines and breaks lactose into glucose and galactose

Question 14

Making lactose-free milk

Answer 14

• Lactase is mixed with alginate gel
• Alginate beads are made that immobilize the enzyme
• Enzyme can then be used repeatedly since it can’t be washed away with the product
• Milk is passed through a mesh with the enzyme for several cycles until no more lactose is detected

Question 15

Role of a fermenter

Answer 15

Designed to optimize the growth of a microorganism such as bacteria - usually a stainless steel structure with a water jacket

Question 16

Features of a fermenter

Answer 16

• Stirrer - keeps everything evenly distributed
• Nutrients are microorganisms are put in
• Sterile air supply
• Probes to measure temperature, pH & oxygen levels
• Water-cooled jacket - keep mixture at optimum temperature
• Product comes out

Question 17

Production of penicillin

Answer 17

1 - penicillium mold naturally produces the antibiotic penicillin
2 - Naturally produced in a fermenter with a solution containing sucrose and penicillium

Question 18

Substances that are produced by fermenters

Answer 18

• Penicillin
• Mycoproteins
• Insulin

Question 19

Genetically modified organisms

Answer 19

• Humans - proteins can be inserted to treat people e.g. insulin with type 1 diabetes
• Herbicide resistant plants - genes can be inserted to make crops herbicide resistant
• Insect resistant plants - Genes can be inserted into crops to give them resistance to pests e.g. bt corn
• Food with improved nutritional qualities - vitamin and amino acid contents can be increased

Question 20

Steps of genetic modification

Answer 20

1. Isolating the section of DNA that makes up the required human gene
2. Cutting the DNA of a bacterial plasmid
3. Inserting the human DNA into the plasmid DNA
4. Inserting the plasmid into bacteria
5. Allowing the genetically modified bacteria to express the gene and make the human protein

Question 21

Restriction enzymes

Answer 21

Cut DNA at particular places

Question 22

Sticky ends

Answer 22

Ends of single-stranded DNA cut by restriction enzymes

Question 23

Recombinant plasmid

Answer 23

Name for the plasmid that has been changed by the insertion of the gene

Question 24

Ligase enzymes

Answer 24

Join sticky ends together to make a complete length of double-stranded DNA