Variation Flashcards
What is variation?
Differences in the characteristics of individuals in a population
What can cause variation?
Genetic causes, environmental causes and a combination of genes and the environment
How do new phenotype variants occur?
Mutations
What is selective breeding?
Breeding plants and animals for particular characteristics
Describe the process of selective breeding
Choose parents with desired characteristic
Breed them together
Choose offspring with desired characteristic and breed again
Continue over many generations until all offspring show the desired characteristic
What are the consequences of inbreeding?
Inherited defects and disease
What is genetic engineering?
Modifying the genome of an organism by introducing a gene from another organism to give the desired characteristic
How have plant crops been genetically engineered?
To be resistant to diseases/herbicides/pesticides, to produce bigger fruits, to give higher yields
How have bacteria been genetically engineered?
To produce useful substances, such as human insulin to treat diabetes
What are enzymes used for in genetic engineering?
Cut out the required gene
What is used to transfer the required gene into the new cell in genetic engineering?
Vector (E.g. bacterial plasmid or virus)
Describe the steps involving adult cell cloning
Nucleus removed from unfertilised egg cell
Nucleus from adult body cell inserted into egg cell
Electric shock stimulates egg cell to divide to form embryo
Embryo develops and is inserted into the womb of an adult female
What is tissue culture cloning?
Using small groups of cells from plants to grow identical new plants
Why is tissue culture cloning of plants important?
Preserve rare species and for growing plants commercially in nurseries
What is cutting as a cloning method?
Simple method used by gardeners to produce many identical plants from a parent plant
