Variation Flashcards
What is variation
Differences in 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 characteristics
Breed them together
Choose offspring with the desired characteristics and breed again
Continue over many generations until all offspring show the desired characteristics
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 organisms to give a desired characteristic
Why have plant crops been genetically engineered
To be resistant to diseases/herbicides/ pesticides
To produce bigger fruits
Higher yields
Why have bacteria been genetically engineered
To produce useful substances such as 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
Bacteria plasmid or virus
Describe the steps involved in 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 an embryo
Embryo develops and is inserted into the womb of the 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
Describe cloning through using embryo transplants
Cells split apart from a developing animal embryo before they are specialised then the identical embryos are transplanted into host mothers
Why is selective breeding used
Disease resistance in food crops
Animals that produce more meat or milk
Domestic dogs/cats with gentle nature
Larger or unusual flowers
What are the disadvantages of selective breeding
Can lead to inbreeding
Reduces variation so whole species can be at risk to same disease
What is a clone
An individual that has been produced asexually and is genetically identical to its parent
Benefits of cloning
Large number of identical offspring produced
Quick and economical
Desired characteristics guaranteed
Risks of cloning
Limits variation and causes reduction in gene pool
Clones may be vulnerable to disease or changed to the environment
Ethical consideration around cloning living organisms
Explain process of genetic engineering
Cell from organism with desired gene
Enzymes used to cut out the desired gene
Cell with vector
Vector taken out of cell and split open
Gene removed is inserted into the vector
Vector is used to insert gene into required cell at an early stage in development
As the organism grows it develops with the desired characteristics from the other organism
What are the benefits of genetic engineering
Potential to overcome some inherited human diseases
Can lead to high value of crops as GM crops have higher yields
Crops can be engineered to be resistant to herbicides, make their own pesticides, or be more resistant to environment
What are the risks of genetic engineering
Genes from GM plants and animals may spread to other wildlife causing harm
May have negative impacts on populations of wild flowers and insects
Ethical concerns - people may manipulate genes of children
Long term effects of heath when eating GM crops have not been fully explored
