Topic 16 - Changing Organisms

Question 1

Selective breeding

Answer 1

An artificial process in which organisms with desired characteristics are chosen as parents for the next generation

This process has to be repeated for many successive generations before having a ‘new breed’ that will reliably show those selected characteristics in all offspring

Question 2

Genetic modification

Answer 2

Changing the genetic material of an organism by removing or altering genes or inserting individual genes from another organism

Question 3

Genetic modification steps

Answer 3

Genetically engineering bacteria to be able to produce insulin:

1. Cut out insulin gene from human cell using restriction enzyme
2. Remove plasmid from bacterial cell. Cut it open using same restriction enzyme. Plasmid acts as vector as it will transfer desired gene
3. Insert cut desired gene into open plasmid using ligase (joins DNA)
4. This produces recombinant DNA
5. Insert recombinant DNA back into bacterium
6. Bacterium is now transgenic, containing genes from another species
7. Bacteria can be grown in bioreactor to produce human insulin

Question 4

How GM plants can improve food production

Answer 4

• crops can be genetically modified to produce poison that kills insects, making them more pest-resistant
• some GM crops can have additional vitamins and improved nutritional value e.g. golden rice produces a chemical that is turned into vitamin A in the human body

Question 5

Transgenic

Answer 5

An organism or cell of one species into which one or more genes of another species have been inserted

Question 6

Vector

Answer 6

A structure responsible for transferring DNA into a cell. They take up pieces of DNA and then insert this recombinant DNA into other cells.

Types of vectors:
- plasmids
- viruses

Question 7

Fermenter

Answer 7

Containers used to grow (‘culture’) microorganisms like bacteria and fungi in large amounts

Question 8

Aseptic conditions fermenter

Answer 8

Cleaned by steam to kill microorganisms and prevent chemical contamination so only desired microorganisms can grow

Question 9

Nutrients fermenter

Answer 9

Used in respiration to release energy for growth and reproduction

Question 10

Temperature fermenter

Answer 10

• monitored using probes and maintained using water jacket
• to ensure optimum environment for enzymes

Question 11

PH fermenter

Answer 11

• monitored using probe for optimum value
• can be adjusted using acids and alkalis

Question 12

Oxygenation fermenter

Answer 12

For aerobic respiration

Question 13

Agitation fermenter

Answer 13

Stirring paddles ensure that microorganisms, nutrients, oxygen, temperature and PH are evenly distributed

Question 14

Cloning steps

Answer 14

1. Take egg cell from organism
2. Remove haploid nucleus from egg cell to produce enucleated egg cell
3. Take body cell from desired organism you want to clone
4. Remove diploid nucleus from this cell
5. Use electric shock to fuse diploid nucleus with enucleated egg cell
6. It will start to divide by mitosis to form an embryo
7. Place embryo into uterus of surrogate mother

Question 15

Cloning

Answer 15

the process of producing identical copies of an organism, or a group of cells, through asexual reproduction

Question 16

Stem cell

Answer 16

Cells that are undifferentiated, meaning they do not have a specific job or function

Question 17

Cell differentiation

Answer 17

the process by which cells become specialised to perform specific functions in an organism

Question 18

Advantages of using stem cells in medicine

Answer 18

• great potential to treat a wide variety of diseases
• relieving the suffering of patients may be more important that the rights of embryos
• organs developed from a patient’s own stem cells reduces risk or organ rejection

Question 19

Disadvantages of using stem cells in medicine

Answer 19

• stem cells grown in lab may become contaminated with a virus, which could be passed on to the patient
• low number of stem cell donors
• uncertainties regarding long-term effects
• it is unethical to take cells from the embryo without consent as the embryo dies