B1 6 Inheritance Flashcards Preview

AQA GCSE Science > B1 6 Inheritance > Flashcards

Flashcards in B1 6 Inheritance Deck (18):
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What are gametes?

Gametes are the sex cells.

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What are chromosomes?

Chromosomes are thread like structures which carry the genetic information found in the nucleus of the cell.

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What is DNA?

DNA is a complex chemical which carries genetic information.

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What is a gene?

A gene is a small section of a DNA molecule.

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What is asexual reproduction?

Asexual reproduction only involves one parent. There is no fusion of the gametes and no variety in the offspring. Asexual reproduction produces clones as their genetic material is identical both to the parent and to the offspring.

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What is sexual reproduction?

Sexual reproduction involves a male sex cell and a female sex cell from two parents. These gametes join together to form a new individual. The offspring from sexual reproduction inherit genetic information from both parents so there is variety as there is mixing of genetic information.

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Why is variation important?

Variety is important as it improves the likelihood of survival of a species.

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EXAMINER'S TIP

Genes control the development of characteristics. Characteristics may be changed by the environment.

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What is a clone?

A clone is an individual that has been produced asexually and is genetically identical to its parent.

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How do you clone plants?

You can clone plants by taking a cutting. Then you place the plant in an ideal environment and it will grow to produce a new plant. You can also clone plants on a large scale. Firstly, you use a mixture of plant hormones to make a small group of cells from the plant you want to clone. Then, you stimulate these cells to produce a new plant. However, this method is expensive.

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How do you clone animals?

You give a good quality cow fertility hormones so that it can produce a lot of eggs. You fertilise these eggs using sperm from a good quality bull. This is often done inside the cow and the embryos that are produced are gently washed out of her womb. At this early stage, the cells of the embryo have not become specialised. The embryo is divided into several individual cells and then each cell grows into an identical embryo in the lab. Transfer the embryos into their host mothers. Soon later, identical calves will be born.

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Process of adult cell cloning:

• Remove the nucleus from an unfertilised egg cell • At the same time, take a nucleus from an adult body cell of another animal of the same species • Insert the nucleus taken from the adult cell into the empty egg cell • Give the new cell a mild electric shock so that it starts dividing to form embryo cells • When the embryo has developed into a ball of cells, insert it into the womb of an adult female to continue its development

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The benefits and disadvantages of adult cell cloning:

BENEFITS: • Clone medically useful animals • Save animals from extinction • It can help infertile couples DISADVANTAGES: • Cloning of human babies- unethical • Reduces variety in a population • Expensive and time consuming

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What is genetic engineering?

Genetic engineering is the changing of genetic information of an organism. A gene is taken from one organism and transferred to the the genetic material of a completely different organism by using enzymes.

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Benefits of genetic engineering:

• Genetically modified food, to improve the growth rates of plants and animals • Genetically engineered bacteria can make the proteins we need • Human engineering

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Disadvantages of genetic engineering:

• Insects may become pesticide resistant due to the overuse of pesticide-forming plants • Some people are concerned about the effects of eating GM food on human health • People may want to manipulate the genes of their future children

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Adult Cell Cloning Diagram:

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Genetic Engineering Diagram:

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