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34 Cards in this Set
- Front
- Back
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In which part of a cell is the genetic information found? (1 mark) |
Nucleus |
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DNA is the chemical that forms the chromosomes |
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Describe the structure of DNA. (1 mark) |
DNA is a long molecule made up of two strands that are twisted together to make a spiral. This is known as double helix. |
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How many chromosomes is present in human body cells? (1 mark) |
46 chromosomes (or 23 pairs) |
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How many chromosomes is present in human sex cells (gametes) (1 mark) |
23 chromosomes |
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Name three characteristics that are genetically controlled. (3 marks) |
Attached or detached earlobes Thumb straight or curved Dimples Eye colour Shape of nose |
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State two reasons why there is a difference in characteristics between individuals (2 marks) |
Factors that have been genetically inherited Environmental factors - conditions in which they have developed |
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State 2 characteristics controlled by environment (2 marks) |
Scars on body due to accidents Hair colour due to artificial colouring |
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State two factors that are a combined cause of variety (2 marks) |
Skin colour changes depending on the environment one lives in Height and weight is affected by the genes and the environment one grow up in |
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What is a gene? (1 mark) |
Genes is a section of the DNA. They control the different proteins and enzymes made in our body |
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What is asexual reproduction? (1 mark) |
Asexual reproduction produces offspring that are genetically identical to the parent |
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Where can you find asexual reproduction? (1 mark) |
In our body cells / in Bacteria |
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What is sexual reproduction? (1 mark) |
Sexual reproduction involves the fertilisation of the gametes to form a new individual |
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What are the gametes in animals called? (1 mark) |
The egg cell and the sperm cells are call the gametes |
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How do parents pass on genetic information to their offspring? (1 mark) |
During sexual reproduction |
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How does sexual reproduction cause variety in offspring? (1 mark) |
There is genetic information from both parents so there is a mixture of characteristics from both |
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Why is variety important? (1 mark) |
There is a greater advantage in making sure that the species survives |
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State the differences between sexual and asexual reproduction (6 marks) |
Asexual reproduction: No fusion of gametes Only one individual needed as the parent No mixing of genetic information No variation in the offspring The genetically identical individuals are known a clones |
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State the differences between sexual and asexual reproduction (6 marks) |
Sexual reproduction: Fusion of male and female gametes Two parents present Mixture of genetic information Offspring are genetically different from parent and from each other |
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What is fertilisation? (1 mark) |
The fusion of the male and female gamete during sexual reproduction |
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Name the three modern cloning techniques (3 marks) |
Tissue culture Embryo transplants Adult cell cloning |
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What is a clone? (1 mark) |
A clone is an individual that has been produced asexually and is genetically identical to the parent |
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Describe the technique of cutting (1 mark) |
Taking a small piece of a stem or leaf and growing it on in the right conditions to produce a new plant |
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Describe tissue cloning (1 mark) |
Getting a few cells from a desirable plant to make a big mass of identical cells each of which can produce a tiny identical plant |
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Describe embryo cloning (1 mark) |
Splitting cells apart from a developing embryo before they become specialised to produce several identical embryos. Insert these embryos into individual host womb of mother. |
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Describe the technique involved in adult cell cloning (6 marks) |
Remove egg cell from ovary Remove nucleus from the egg cell The egg cell is now empty Transfer nucleus from body cell into the empty egg cell The egg cell now has the nucleus of a body cell Allow the egg cell to grow into a ball of cells Insert embryo into the womb of the female Offspring is a clone |
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What is the advantage of cloning cattle embryos? (1 mark) |
It allows the production of far more claves from the best cows |
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State one economic issue raised by embryo cloning (1 mark) |
Involves a lot of money for the technology involved |
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State one disadvantage of adult cell cloning techniques (1 mark) |
Reduced variety in a population |
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What is genetic engineering? (1 mark) |
Genetic engineering involves transfer of genes to the cells of animals and plants at an early stage of their development so that they develop desired characteristics |
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Describe the method used in genetic engineering (1 mark) |
A gene from one organism is taken and transferred to the genetic material of a completely different organism |
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How is a gene ‘cut out’ of one organism? (1 mark) |
Using enzymes |
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State the disadvantages of genetic engineering (3 marks) |
Insects may become pesticide-resistant if they eat a constant diet of pesticide forming plants Effect on human health of eating genetically modified food People may want to manipulate the genes of their future children |
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State the advantages of genetic engineering (5 marks) |
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