Chapter 31 - Genetic engineering Flashcards
Define genetic engineering
Direct manipulation of an organisms genetic material.
Name three processes of genetic engineering
- Insertion of genes
- Alteration of genes
- Deactivation of genes
Describe the principles of using a vector in GE
- Chromosome or locus containing the gene is identified and isolated
- Restriction enzyme is used to cut DNA into segments and remove the required gene
- A bacterium of fungus is used
- Plasmids are removed from bacterium or fungus
- Plasmids cut open to form a strand
- Removed gene is inserted to form recombinant DNA
- Ligase used to join Recombinant DNA into a plasmid again
- Plasmid inserted back into host cell
- The bacterium reproduces by mitosis
Advantages of using artifically produced insulin
- Cheaper to extract and purify
- Identical to human insulin
- No allergic reactions occur
- Constant supply available
- The body shows a more rapid response to the hormone
Advantages of using genetically manipulated crops
- Can be modified to produce natural insecticides
- Can be herbicide resistant
- More draught resistance
- Increased nutritive quality
- Increased crop yield
Describe the goal of the human genome project
- To map the entire DNA base sequence of every chromosome in the human genotype
- Identify all genes in the human DNA sequence
- Working out the nucleotides in each gene
- Determining what each gene codes for
- To determine the precise role of each gene
How is the human genome project utilised in the modern world?
Satisfies the human quest for knowledge
Identifying genes causing genetic diseases
Imroved treatment of genetic diseases
Prevention of genetic diseases
Potential problems with irresponsible GE
- Transferred genes may have an effect on consumers, causing genetic disorders
- Unwanted genes may cause resistance in weeds to weed killers
- New extremely dangerous pathogens could be created accidentally
- Increased antibiotic resistance in bacteria
Define variation
- Differences existing in a species
- Result from mutations or environmental factors
Continuous variation
- Smooth gradation between individuals
- Caused by genetic and environmental factors
- No distinct catagories
- Height, skin colour, nose shape, etc
Discontinous variation
- Extremes
- You have a characteristic or you don’t
- Genetic ONLY
- Blood groups, gender, etc
Genetic variation
- Inheritable
- Involves different alleles
- Random fusion of gametes
- Mutations produce new alleles
Environmental variation
- Non-inheritable
- Acquired characteristics from environment (scars, hair lenght, etc)
Define a genetic mutation
The sequence of bases is not completely copied during replication. Change in instructions for protein synthesis occurs.
Faulty proteins or no proteins at all (cause of albinism) occurs
Define a mutagen
Factors increasing mutation chances
Also increases the rate at which mutations occur
Define natrual selection
- Variations occuring among individuals in a population to give those individuals a better chance of survival. Strongest survive, interbreed. Offspring receive favourable alleles.
Describe evolution
All organisms descend from common ancestors. Populations modify in response to environmental changes. These changes occur over millions of years.
Now. Explain how natural selection leads to evolution. It’s not that hard. Use logic.
- Individuals in a population have reproductive potential
- Many fail to survive and die
- Many fail to reproduce
- This occurs due to environmental factors
- Those best adapted to survive pass on their alleles to offspring. Variation occurs and phenotypes gradually change.
- Gene pools change.
- Over time, this leads to evolutionary changes.
- After many years, a new species may arise.
Sickle cell anaemia is a recessive gene. So what happens in the Heterozygous state? (Refer to malaria)
The person will NOT have sickle cell anaemia, but is LESS likely to suffer from malaria
What are antibiotics?
Substances used in medicines that destroy disease causing bacteria
- Earliest antibiotic is called penicillin, produced from a fungus
- Many diseases can be successfully treated by antibiotics
What is the effect of antibiotics on bacterium cells?
Antibiotics cause the cell walls of bacteria cells to become weaker during production. The pressure inside the cell can not be contained and the bacterium cell bursts and dies.
Why do antibiotics NOT effect virusses?
Well… Let’s see. First off, virusses are NON-LIVING and therefore they cannot DIE. Virusses are non-cellular, have not cytoplasm and cell walls, and no cellular pressure, and cannot burst.
So antibiotic-resistant bacteria is now a huge problem. What is this?
- Antibiotics are widely misused
- Patients do not complete antibiotic courses
- They stop taking antibiotics when they start feeling better (idiots)
- A partial course only kills weak bacteria
- Natural selection occurs. Strong bacteria mutute and develop a resistance against the antibiotics, and the offspring inherits this trait.
- Well done, you have now infested your body with a super-incurable bacterium cell. Dit sal jou leer.
How do we prevent antibiotic resistance?
- Antibiotics should be used sparingly
- Courses must be completed
- Reduce the need for antibiotcs by improving health and living conditions
Now will follow an explination of how bacterium cells develop resistance due to SELECTIVE PRESSURE. Pay close attention to all the different terms used.
- Antibiotic resistance is natural selection
- Antibiotics place selective pressure on bacterium cells
- Alleles providing no resistance will disappear from the population
- Resistant allele passed on to offspring
The frequency of this allele increases - The strongest cells survive
- More advantages phenotypes are now passed on more frequently
How does artificial selection and the production of a variety of plants and animals affect the economy?
- Artificial selection used to create breeds which cannot occur naturally
- Many organisms are genetically modified by humans
- Leads to desirable characteristics
- Best organisms are chosen to produce the next generation, while worse organisms are not allowed to breed
- Leads to high milk production, high yield, resistance to drought in the respective organisms
- Therefore, artificially selected animals and plants can boost an economy.
Name some advantages artificial selection brings about, concerning crops
- Climate adapted crops
- Disease resistant crops
- High yielding crops
- More nutritious crops
Name some advantages artificial selection brings about, concerning cattle
- Disease resistant cattle
- Cattle produce more milk and/or meat
State the importance of maintaining a gene bank and rare breeds
- Gene banks are collections of different breeds and wild relatives of domesticated strains
- A plant gene bank includes a collection of seeds or tissue cultures
- Seeds may contain different genes
- Which can be bred into desirable crops when required
- Can be used for genetic engineering
Examples of animal gene banks
- Cold storage of sperm, eggs or embryos
- Rare breeds can be conserved
- Zoos and nature reserves where animals are protected also serves as a gene bank
- Whole ecosystems are conserved
