Unit B1.6/Unit B1.7 Cloning and Evolution

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Genetic Engineering- Insulin from bacteria

Can be used to produce insulin from bacteria:

1. Burst bacterium to release plasmid before cutting the plasmid with a enzyme

2. Burst a human cell before removing chromosome and cutting out insulin gene with the same enzyme.

3. Mix the cut plasmid (Bacterial DNA) and insulin gene with a different enzyme and they will stick together.

4. Put plasmid into a bacterial cell- divides every 20 minutes. Each cell has a copy of the human insulin gene- 1,000,000 insulin genes in a day

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Genetic Engineering- Advantages and disadvantages

Advantages of genetic engineering:

1.Plants could be developed to grow in poor, dry areas of the world

2.Making food more available and cheaper e.g arctic ice fish gene in strawberries allows them to grow in colder conditions

3.By putting human insulin gene into bacteria it means you can produce large volumes of insulin at a consistent quality fast

Disadvantages of genetic engineering: 

1.Crops are made infertile so Africans have to buy new seeds each year

2.Everyone is supposed to be different- genetic engineering would make us all the same

3.Lots of training and expensive equipment needed to grow bacteria like this.

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Cloning Plants

1. Clones are produced asexually from one parent- this means they are genetically identical to their parent

2. Plants clone quite easily e.g. strawberries

3. Gardeners make copies of plants by cloning this is called taking cuttings:

-A piece of leaf and stem is removed

-Treated with bleach to prevent infection

- Hormone rooting powder may be used to make the roots grow faster

-Planted in a suitable growth medium to grow into a whole plant

4. Cuttings look identical to their parents because they have the same genetic information or genes on their chromosomes so they have the same characterisitcs

5.They may be different due to environmental differences- light, water etc.

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Cloning Tissue

1. Tissue culture means we can clone a plant from a much smaller piece of tissue, so thousands of new plants can be produced from one successful parent.

2. Using the correct growth hormones, we can make a few cells grow into a large number of cells

3.Changing the hormones mean that these cells can then go on to make a whole plant- tissue cloning

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Cloning Animals

Animals are cloned in embryo cloning, Fertility hormones make a cow produce many eggs they can be washed out of the cow collected and fertilized by sperm from a selected bull. The fertilized eggs will start dividing. It can be treated to break it up into different cells. At this early stage each of the cells can go on to produce a whole, genetically identical calf. These cells are implanted into surrogate mothers (not the real mother)- the real mother cow could only carry one calf but if we use lots of cows treated with hormones to make them ready to accept the embryo, we can produce lots of calves, although they are not genetically related to the surrogate (host) cow. Embryo cloning can make lots of identical copies so more cows with high milk content yield are available, or it could be used to make many identical animals modified to produce medically useful compounds such as insulin.

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Adult Cell Cloning

To clone an adult cell form a sheep:
1. Remove a cell from the sheep you want to clone, remove the nucleus and discard the rest of the cell

2. Take a egg cell from another sheep and remove and discard the nucleus leaving the empty cell

3. The nucleus from the sheep you want to clone is inserted (diploid) into the empty egg cell which creates a complete cell.

4. Implanted into surrogate mother when there are a few cells

5. Genetically identical sheep born.

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Adult Cell Cloning- Possible uses

Possible uses of adult cell cloning:

1. To make identical copies of valuable animals

2. The creation of children without inherited illneses

3. To grow organs for people needing transplants.

The disadvantages of adult cell cloning is that it may take many attempts until you are successful and there is no differences or variation between clones.

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The Theories of Evolution

The different theories on evolution:

Evolution is about how living things have changed over millions of yearsLamarck and Darwin had different ideas about how this happened. Lamarck believed new structures appeared when they were needed and those that aren't used degenerate . He also proposed that changes acquired in the lifetime of organisms were then passed on to the offspring.

Darwin on the other hand proposed that organisms with the best adaptations to their environment survive and have offspring which inherit those adaptations. Useful characteristics become more common. Less well adapted organisms die out. All organisms over reproduce, so individual organisms have to compete, particularly for food . Disease and predators cause a large number of organisms to die out.

This is called the struggle for survival. This struggle leads to the fittest surviving. In other words, those organisms with the most suitable characteristics are the most likely to survive. This is called natural selection. These gradual changes are the mechanism by which evolution occurs.

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Evolution and Classification

Classification is the organisation of living organisms into groups based on their similarities and differences.

It is based on the appearance of and lifestyle of living organisms- how closely related organisms are.

This can be drawn in evolutionary trees.

We use DNA to prove how closely organisms are linked (evolutionary relationships) Closer related = more similar DNA = more recent common ancestor

The closer organisms are on a evolutionary tree, the more closely related, the more similar they are.

The biggest groupings are kingdoms- animals, plants

The smallest grouping is a species which can be interbred to make fertile offspring.

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Mutation and Evolution

Is mutation important in evolution?:

1. Offspring are only produced by successful parents- ones that have bred. This is natural selection. The offspring will probably have these successful characteristics since they will have the parents successful DNA (genes).

2. Mutation is a change in genes by chance. This change might make an organism better adapted to an environment, so it would have more offspring and its genes would be passed on.

3. Mutation may make sudden changes in a species.

4. But since mutation is by chance, it will usually not produce offspring that are better adapted to the environment. It may be damaging.

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