information that results in plants and animals having similar characteristics to their parents
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how are genes passed on
in the sex cells (gametes) from which the offspring develop
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what causes genetic variation
combination of genes from two parents
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what do different genes do
control the development of different characteristics of an organism
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Differences in the characteristics of different individuals of the same kind may be due to differences in:
the genes they've inherited (genetic causes), conditions in which they've developed (environmental) or a combination of both
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what does the nucleus of a cell contain
chromosomes
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how many chromosomes does a human cell nucleus contain
23 pairs (one chromosome from each parent)
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what do chromosomes carry
genes that control the characteristics of the body
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what are alleles
different versions of the same gene
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what happens in sexual reproduction (4)
male and female gametes fuse (join), the mixture of the genetic information from two parents leads to variety in the offspring
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what happens in asexual reproduction (5)
no fusion of gametes and only one individual is needed as the parent, there is no mixing of genetic information so no genetic variation in the offspring. These genetically identical individuals are known as clones
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what is cutting
a cheap and quick way of producing new plants by taking cuttings off older plants, new ones are genetically identical (clones)
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cloning technique 1
tissue culture: using small groups of cells from part of a plant to form clones
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cloning technique 2
embryo transplants: splitting apart cells from a developing animal embryo before they become specialised, then transplanting the identical embryos into host mothers
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cloning technique 3 (part 1)
adult cell cloning: the nucleus is removed from an unfertilised egg cell. The nucleus from an adult body cell, eg skin cell, is then inserted into the egg cell
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(part 2)
An electric shock then causes the egg cell to begin to divide to form embryo cells. These embryo cells contain the same genetic information as the adult skin cell
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(part 3)
When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its developmen
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+ of cloning
study of clones can lead to better understanding of embryo development, ageing, age-related disorders/ can preserve endangered species
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- of cloning
if population closely related and new disease appears all will be wiped out/ cloned animals might not be as healthy/ possible human clones could involve unsuccessful attempts - eg. disabilities
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what happens in genetic engineering
genes from the chromosomes of humans and other organisms can be ‘cut out’ using enzymes and transferred to cells of other organisms
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what can these genes be transferred to
cells of animals, plants or microorganisms at an early stage in their development so that they develop with desired characteristics/ to crop plants
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what are GM crops and 2 examples
crops that have had their genes modified: ones that are resistant to insect attack or to herbicides
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+ of GM crops
increases yield/ can contain nutrients missing from diets of developing nations/ already grown in other countries with no problems
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- of GM crops
effect on populations of wild flowers and insects, reduces biodiversity/ uncertainty about the effects of eating GM crops on human health
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Other cards in this set
Card 2
Front
how are genes passed on
Back
in the sex cells (gametes) from which the offspring develop
Card 3
Front
what causes genetic variation
Back
Card 4
Front
what do different genes do
Back
Card 5
Front
Differences in the characteristics of different individuals of the same kind may be due to differences in:
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