Gene technologies Flashcards
(12 cards)
What is genetic engineering?
A process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic
Describe the process of genetic engineering
- A useful gene (the gene of interest) is cut from the DNA of one organism using an enzyme called a restriction enzyme
- This enzyme breaks bonds between nucleotides
- Restriction enzymes cut the DNA in a staggered way leaving short sections of single-stranded DNA at each end of the gene-these sections of single-stranded DNA are called sticky ends
- The bacterial plasmid DNA is cut open using the same restriction enzyme- they are complementary to the ends of the useful gene
- The useful gene and the plasmid DNA are mixed and the gene is inserted into the plasmid
- Hydrogen bonds form between the complementary bases
- The enzyme DNA ligase joins the plasmid DNA and the useful gene together
- The plasmid is now called a recombinant plasmid and is inserted into a bacterial cell- acts as a vector, carrying the gene into the bacterial cell
- The bacterial cell is now a GMO; it can be cultured by cloning and the cell can use the gene that has been inserted into it to make a protein
Give 3 examples of genetic engineering in different cell types?
BODY CELLS:
-Cystic fibrosis (CF) affects cells in the lungs
-GE allows a gene to be added to lung cells to enable the cells to produce a therapeutic protein which reduces the symptoms of the condition
STEM CELLS:
-Sickle cell anaemia affects the production of haemoglobin proteins- red blood cells carry haemoglobin molecules with a slightly altered shape which are unable to transport oxygen as efficiently
-GM bone marrow cells could be used to create red blood cells that carry haemoglobin proteins with a shape that is better able to transport oxygen
GAMETE CELLS:
-A therapeutic gene added to a gamete cell will be found in every cell in the body of a person that develops from GM gametes
-This could potentially prevent all offspring of a treated individual developing a genetic condition
What are some risks of genetic engineering?
- Introducing new genes might cause unexpected consequences, especially if the genes are inserted wrongly
- The therapeutic gene would be passed on to each new generation of offspring if added to a gamete cell, so unexpected results could cause long-term negative outcomes
- There are also important ethical issues surrounding the concept of modifying human genes
What are stem cells?
undifferentiated cells which can develop into many different cell types
What is the difference between EMBRYONIC stem cells vs ADULT stem cells?
EMBRYONIC:
- Totipotent; can differentiate and develop into any type of specialised cells
- Come from an embryo
ADULT:
- Multipotent; they are undifferentiated cells which can only differentiate into a SMALL NUMBER of different cell types
- Can come from liver, heart, brain, skin, bone marrow
How can embryonic stem cells be used in medicine?
Could be used to treat conditions which occur because body cells are damaged/ destroyed:
USED TO:
-Treat diabetes by replacing insulin-secreting cells in the pancreas
-Treat burns by replacing damaged skin tissue
-Replace neurons damaged by the spinal cord
-Replace cells in the heart damaged by a heart attack
How can adult stem cells be used in medicine?
Adult stem cells can be transplanted into patients to treat some diseases, e.g. certain cancers
Compare the benefits vs the risks of using stem cells in medicine
Risks:
- Unethical; embryo’s right to life
- Unable to give consent
- Rejection
Benefits:
- Totipotent
- Destroyed anyway
- Therapeutic cloning exists; can reduce the risk of rejection
Describe how selective breeding is carried out
- Animals with desirable characteristics, e.g. rapid growth rate, are selected for breeding.
- These animals are bred together.
- The animals with the most desirable characteristics are selected from the offspring.
- These offspring animals are then bred together.
- This cycle is repeated over many generations.
- Over time the desirable characteristic starts to increase in the population, e.g. animals which have a higher and higher growth rate.
What is meant by the term “inbreeding”? And how does this impact domesticated animals?
INBREEDING=
“Breeding closely related animals over many generations”
-Increases the likelihood of genetic conditions arising in the animals;
-Alleles that cause genetic conditions are often recessive
-If genetic variation is low, there is an increased chance of being homozygous recessive & therefore developing the conditions
-Reduction in genetic variation in the animal population can also reduce the population’s ability to adapt to a changing environment
What are some ethical issues with selective breeding?
- Selective breeding can affect the welfare of animals
- The characteristics that are selected as desirable to humans are not always desirable to the animals that are produced;
- Don’t aid survival
