Genetic variation and its control

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  • Created by: Heather
  • Created on: 28-05-14 10:35
Where are chromosomes found in a cell?
The cell's nucleus,
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What do chromosomes contain?
Many genes
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What is a gene?
A small section of DNA that carried coding for particular proteins,
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What do genes control?
The development of different characterisitics of an organisms.
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How many chromosomes are in cell's of a human? Is this the same foe other species?
Human have 46 chromosomes but it varies from species to species,
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What are the differences between individual species called?
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Why do offspring only look a little like their mother and father and not clones?
Due to fertilisation where a female and a male gamete each with half the humber of chromosomes-23-join together to make a human cell of 64 so it is a mixture of genes from the father and mother,
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what are some examples of inheritied variation in humans?
-Eye colour, -Hair colour, -Skin colour,
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Variation doesnt always just come from inherited genes. What is another facotr that can cause variation and examples?
Environmental factors-Climate, diet, accidents, culture, lifestyle, accent,
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What are sex cells called?
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What are the male and female gametes?
male-sperm, Women-egg,
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How does sexual reproduction occur?
When a male and female gamete join which is called fertilisation,
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How many chromosomes does a sex cell contain?
23-Hald the number in a human cell,
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What is asexual reproduction?
-It needs only one parent, -It doesnt involve the joining or fertilisation of two gametes, -It produces a clone identical to the parent, -There is no gentic variation,
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Give an example of an sea creature that produces asexually?
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Why is artifical cloning in plants used?
-It allows a successful variety of a plant to be produced commericiallyu and cheaply in a short amount of time on a large scale,
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What are the two ways of cloning a plant?
Cuttings and tissue culture,
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How does taking a cutting work?
-A branch from the parent plant in cut off, -Its lower leaves are removed and the stem is planted in damp compost with plant hormones to encourage new roots,-New roots develop after a few weeks and a new plant is produced,
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How does tissue culture work?
-Tissue samples are scraped from a parent plant, -These are places in Agar growth medium containing nutrients and auxins,-Samples develop into tiny plantlets, -Plantlets are then planted into compost,
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What are the two examples of cloning an animal?
-Embrp transplants, -Adult cell cloning,
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How does adult cell cloning work?
-An untertilised egg cell is taken from the mother animal and the nucleus is removed, -The adult body cell from the animal you are trying to clone is taken and the nucleus is removed and put in the egg cell, -Eletric shock applied to make egg cell,
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How does adult cell cloning work? (2)
fuse and divide to form an embryo, -This embryo is then inserted into the womb of the suffraget adult female, -The embryos grow into a baby which is genetically identical to the animal which donated one of its body cells,
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How does embryo transplants work?
-A developing embryo is removed from a pregnant animal at an early stage before the cells have had time to become specialised, -The cells are seperated from one another and are then grown in a laboratory to ensure they grow,
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How does embryo transplants work? (2)
-They are then transplanted into host mothers, -When the offspring are born, they are identical to one another and genetically relaetd to the original pregenant animal but not the host animals,
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How does genetic engineering work?
-Enzymes can cut pieces of DNA from one organism and join them into a gap in the DNA of another organism. This measn new organisms with the inserted gene has the useful genetic information from the other,
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What is the difference bedtween genetic engineering and cloning?
Cloning prodcues exact copiues but in engineering, it prodcues a uniue set of genes, Also in cloning, genes are copied within the same speices but genetic engineering allows genes to be swapped across species,
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Describe gentic engineering of allowing bacteria to produce insulin form a human hormone?
-The gene for making enzymes is removed from the human cell.-Enzymes cut out the specific insulin gene, -A plasmid is then taken from the bacterium and a small section is removed with enzymes and the insulin gene, -Plasmid inserted bacteria-multiply
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What are the advantages of genetic modification of crop plants?
-They have incrased crop yileds so it si useful for feeding a growing population, -USeful characteristics make it easier to grow,
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What are the disadvantages of genetic modification of crops?
-Unethcal-it is distrubing the life cycle, - advantageous charatcertisis coudl lead to disrubtion in biodiversity, -Could harm human health,
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Card 2


What do chromosomes contain?


Many genes

Card 3


What is a gene?


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Card 4


What do genes control?


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Card 5


How many chromosomes are in cell's of a human? Is this the same foe other species?


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