B1.7
- Created by: Meganallam
- Created on: 15-05-17 09:56
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- B1.7 Genetic Variation and its Control
- why organisms are different
- the information that means plants and animals have similar characteristics as their parents is carried by the genes
- genes are passed on in the sex cells called gametes.
- different genes control the development of different characteristics of an organism.
- genes act on a molecular level to develop characteristics that can be seen.
- the nucleus of a cell contains chromosomes
- chromosomes carry genes that control the characteristic of the body.
- differences in characteristics are due to differences in three things.
- 1. the genes they have inherited.
- 2. the conditions in which they have developed
- 3. a combination of both
- the information that means plants and animals have similar characteristics as their parents is carried by the genes
- Reproduction
- there are two forms of reproduction
- sexual = the fusion of male and female gametes. this leads to variety in offdpring
- asexual = no fusion of gametes and only one parent needed. creates genetically identical individuals (clones)
- Tissue Culture
- using a small group of cells from part of a plant
- embryo transplants
- splitting apart cells fro a developing animal embryo before they become specialised then transplanting them into host mothers.
- adult cell cloning
- 1. the nucleus is removed from an unfertilised egg cell. then the nucleus from an adult body cell is inserted into the egg cell. an electric shock stimulates the cells to divide in to embryo cells. .
- 2. these contain the same genetic information as the adult body cell. when the embryo has developed into a ball of cells it is inderted into a host mother.
- 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
- genes can be transferred to the cells of animals, plants or microorganisms at an early stage in their development so that they develop with desired characteristics.
- new genes can be transferred into crop plants. these are called GM crops.
- GM Crops include ones that are resistant to insect attacks or herbicides
- GM crops show increased yields
- there are concerns with the effect on wild flowers and insects and the effect of eating them on human health
- there are two forms of reproduction
- why organisms are different
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