Selective Breeding, Cloning And Genetic Engineering Flashcards
(23 cards)
What is selective breeding
The process in which humans breed plants and animals for particular genetic characteristics
By breeding a member of a species with a desired trait..
that traits frequency becomes more common in the next generations
How can you end up with all offspring showing a desired characteristics
Keep breeding the offspring with the desired characteristics over many generations until all the offspring show the desired characteristic
The desired characteristic can be used for what
Appearance and usefulness such as:
- disease resistant crops
- animals that produce more meat/milk
- larger more unusual flowers
- more gentle temperament dogs
Problems with selective breeding - new disease and reduction in the gene pool
- More chance of the population the be wiped out completely by disease: Reduction in the gene pool - the number of different alleles in the population which means the members of a species are closer together, meaning that possibly none of the species will have a resistant gene to a disease and can all be fully wiped out
3 disadvantages of selective breeding
- Can lead to a reduction in the gene pool
- Higher chance in an allele of a harmful genetic disease or defect is passed on
- New diseases and defects can occur due to the reduced gene pool
What is genetic engineering
The process of modifying the geonome of an organism by transferring genes to achieve desired characteristics
2 uses of genetic engineering
- Plant crops to be resistant to diseases and produce bigger and better fruits
- Bacteria cells have been genetically engineered to produce useful substances like human insulin to treat diabetes
Organisms that have been genetically engineered and given genes from other organisms are known as
Transgenic
Crops that have been genetically engineered and have had their genes modified are know as what
Genetically modified
What is the process of genetic engineering (1-6)
- Scientist use restriction enzymes to cut a segment of DNA that contains the gene with the desired characteristic. This leaves sticky ends to the gene
- A plasmid is extracted from a bacterium
- The plasmid is cut with the same restriction enzyme
- The plasmid and gene are joined together using the enzyme ligase, forming a hybrid/ recombinant plasmid
- The recombinant plasmid is put back into the bacteria cell, acting as a vector as it transfers the gene from one organism to the target (TRANSGENIC) organism
- The vector cell (bacteria cell) is then inserted into the required cells
Benefits of genetically modified organisms
Nutritional value improved
Can grow easier - higher yield
Ability to be pest resistant
Longer shelf shelves
Reduces economic cost and carbon footprint - less land needed
Examples of genetic engineering
Sheep to produce specific substances in their milk
Genetically modified crops to increase size
Treating diabetes with the insulin produced
Risks of genetically modified organisms
New traits can cause new health problems
Unknown effects of removing traits
Some governments disagree with it
What is cloning
Genetically identical clones of an organism - asexual eproduction
What are the 2 types of cloning in plants
Cuttings
Tissue culturing
What are the 2 types of cloning in animals
Adult cell cloning
Embryo transplants
Describe the process of tissue culturing and its benefits
- A few plant cells are put in a growth medium with hormones and they then grow into clones of the parent plant.
-Advantages - Can be made very quickly, in very little space and grown all year round, can also be used to preserve rare plants by making lots of them
Describe the process of cloning by
cuttings
3 steps
- A shoot cutting is taken from the plant with the desired characteristics
- Place this cut end it rooting powder and in moist compost to prevent wilting
- Plant produced is genetically identical to original plant
Describe the process of cloning by embryo transplant
3 steps
- Sperm taken from the prize male animal and female is inseminated with the sperm.
- Zygotes develop into embryos in female and then are removed from the uterus, the embryos are then split into several smaller embryos which each grow into a new calf
- These embryos are then placed into the uterus of the foster mother
- The new embryos will be genetically identical to each other but will not share genetic material
Host mother known as surrogate
Describe the process of cloning by adult cell culturing
4 steps
- Nucleus is removed from an unfertilised egg (ovum), which is now enucleated
- The nucleus from an adult body cell, such as a skin cell, is inserted into the egg cell, the nucleus contains genetic information
- An electric shock stimulates the egg cell to divide by mitosis to form an embryo, which contain the same genetic information as the adult skin cell
- When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female (surrogate) and continues ti develop
Positives of cloning
5
Rare plants can be saved
Process is simple and quick
Allows mass production in short amount of time
Leads to better embryo understanding
Negatives of cloning
4
Ethical issues - morally wrong to manipulate cells without consent
Mass production leads to reduced gene pool
Worries of cloning of people
