4 2 genetic modification

The selective breeding process involves:

The purpose of selective breeding is to improve the yield from crops and domesticated animals.

Features that might be selectively bred for in plants include:

Features that might be selectively bred for in animals include:

Tissue culture is the process of growing cells or tissues in a nutrient medium.

Nutrient agar provides a growth medium for cells to grow and divide, facilitating the tissue culture process.

A callus is a mass of unspecialised cells that develops on the nutrient medium from the initial tissue sample.

True. All of the components must be sterilised prior to tissue culture to ensure that the correct cells grow, and to avoid infection.

The cells of a callus might be treated to encourage them to differentiate into particular cell types. E.g. the cells in a plant callus might be treated to encourage them to develop into roots or shoots.

Tissue culture can be used in plant breeding as follows:

Tissue culture can be used in medical research as follows:

Genetic engineering is a process by which the genome of an organism is altered to provide it with desirable characteristics.

Desirable characteristics that can be introduced by genetic engineering include:

Restriction enzymes are used in genetic modification to cut DNA at specific locations, allowing for the isolation of genes and the insertion of genes into vector DNA.

True. During genetic engineering the desired gene is isolated using the same restriction enzyme that is used to cut the vector DNA. This is because:

DNA ligase in genetic modification forms the bonds between adjacent DNA fragments. This joins DNA fragments together to form a continuous DNA strand.

Vectors are mechanisms by which DNA is transferred into new cells, e.g. plasmid vectors.

Plasmids in genetic engineering are a form of vector, allowing DNA to be transferred into bacterial cells.

Crops been genetically modified to contain genes from *Bacillus thuringiensis *that code for production of a toxin known as Bt toxin.

The advantage gained from growing Bt crops is that the crops produce Bt toxin; this toxin kills insect pests that eat any part of the plant, so reducing pest damage and increasing yield.

Advantages and disadvantages of growing pest resistant crops include:

Biological control is the use of living organisms to control pests and weeds, so increasing crop yield.

Advantages and disadvantages of using biological control in agriculture include:

False. Fertilisers are used to provide the soil minerals that crop plants need to grow, e.g. nitrates and magnesium ions. Unwanted weed growth is prevented by the use of herbicides, also known as weedkillers.

Advantages and disadvantages of fertiliser use in agriculture include:

False. Some feel that the health effects of consuming GM crops over long time periods have not been thoroughly investigated.

Potential benefits of genetic engineering in agriculture and in medicine include:

Potential risks of genetic engineering in agriculture and medicine include:

False. Some individuals may develop disease resistance as the result of mutation, so selective breeding from these individuals over time can result in disease resistant populations.

Problems that can be caused by selective breeding include:

The Human Genome Project was the international research project that sequenced the entire human genome.

Possible medical applications of the data from the Human Genome Project are: