Selective Breeding and Genetic Engineering

Humans choosing which organisms breed, to produce desired characteristics.

Artificial selection.

Choose parents, breed them, select the best offspring, and repeat.

The characteristic only becomes stronger gradually.

Disease resistance, large fruit or high yield.

High milk yield, fast growth or good wool.

Wild cabbage.

Reduced genetic variation.

Breeding between close relatives.

It increases the chance that harmful recessive alleles come together.

Breathing problems in short-faced breeds, or hip disease.

In natural selection the environment chooses, and in artificial selection people choose.

A single disease could kill all of the plants.

No. It can only use the variation that already exists.

It takes many generations to produce a change.

Thinking that individuals change. Only the proportion of alleles in the population changes.

Growing cells or tissues in a sterile dish, with nutrients.

A small piece of tissue taken from a plant for culture.

Microorganisms would grow faster than the cells and spoil the culture.

Nutrients and plant hormones.

A mass of undifferentiated cells.

Shoots and roots, making plantlets.

Yes. They are clones.

Cells at the shoot tip are often free of viruses.

Making many copies of a plant with a useful feature, or growing GM plants.

It can produce many plants from a small sample, without harming wild populations.

Testing drugs on cultured cells, or growing cancer cells to study them.

It is expensive, and the clones have no variation.

It is done in the lab, with controlled conditions.

Skin cells grown to make skin grafts.

Contamination by microorganisms.

Saying the plants are different. They are clones, and so are genetically identical.

Modifying the genome of an organism by adding a gene from another organism.

An organism with genes that have been changed by genetic engineering.

All organisms use the same genetic code.

Human insulin.

1982.

The pancreas of pigs and cattle.

A carrier, such as a plasmid, used to put a gene into a cell.

A small ring of DNA in a bacterium.

Insect-resistant crops, herbicide-resistant crops or golden rice.

A GM rice that makes beta-carotene, which can be turned into vitamin A.

Putting a healthy gene into a patient's cells.

Genetic engineering can add genes from any species, in one generation.

A fermenter.

The rules that link triplets of bases to amino acids, and which are the same in all living things.

No. It moves a gene or a few genes.

Saying the bacteria make a copy of the person. They only make the protein from the gene.

It cuts DNA at a specific base sequence.

Short unpaired stretches of bases at the ends of DNA cut by a restriction enzyme.

The same enzyme cuts both pieces, so the unpaired bases are complementary.

Joins pieces of DNA together.

DNA formed from two different sources joined together.

A carrier that moves the gene into a host cell, such as a plasmid.

They are small, copied in bacteria, and easily taken up.

Viruses.

Cut the gene, cut the plasmid, join with ligase, put into the host, grow and collect.

So that the sticky ends are complementary.

T T A A.

They grow and reproduce quickly.

It shows which bacteria have taken up the plasmid.

In bacteria, which use them to defend against viruses.

The protein product, such as insulin.

Mixing up ligase and restriction enzymes. Restriction enzymes cut, and ligase joins.

A crop with genes changed by genetic engineering.

Bacillus thuringiensis.

A toxin that kills certain insect larvae.

The plant makes the toxin, so insects that eat it are killed.

Maize and cotton.

Higher yield, and less spraying with insecticide.

Natural selection favours the insects that survive the toxin.

A part of the field with non-GM crop, to keep non-resistant insects.

The toxin might harm non-target insects, or the crop might replace other plants.

The spread of a modified gene to other plants, such as wild relatives, by pollen.

The seed is patented, and often has to be bought new each year.

Vitamin A deficiency.

No evidence of harm has been found, although some people want more long-term studies.

Herbicide-resistant soy, or golden rice.

It makes its own protection.

Saying that the toxin is made by the farmer. The plant itself makes it, from the transferred gene.

They replace the minerals that are taken from the soil when crops are harvested.

It is used to make proteins and chlorophyll.

Stunted growth and yellow leaves.

Nitrogen, phosphorus and potassium.

Rapid growth of algae caused by too many nutrients, and then death of aquatic life.

Bacteria use up the oxygen as they break down the dead plants and algae.

Higher yield.

Eutrophication, or the cost.

Using a living organism to control a pest.

Ladybirds eating aphids, or parasitic wasps used against whitefly.

No chemical pollution, and it is specific.

It is slow and may not remove all of the pest, or the control organism may become a pest.

They did not control the beetles, and became a pest themselves.

Other factors, such as light or water, become limiting.

Each method has limits, so using several reduces the problems.

Saying that fertiliser kills the fish directly. It is the loss of oxygen.

Weigh up the benefits and drawbacks, and reach a judgement.

Higher yield, pest resistance, or more nutrients.

Pests may become resistant, or genes may spread to wild plants.

Some people think it is wrong to interfere with genes.

It is safe, cheap and available in large amounts.

The vector could put the gene in the wrong place, or the immune system could attack it.

The change would be passed on to later generations.

Higher yields, or disease-resistant crops.

Reduced variation and inbreeding.

Breeds with health problems, such as breathing difficulties.

Farmers may depend on companies and have to buy seed each year.

Having a reliable supply of enough nutritious food.

Genetic engineering.

Genetic engineering.

A conclusion with a reason.

Listing points without a conclusion or evidence.