Module Six - Genetic Change Flashcards
Mutation Biotechnology Genetic Technologies
what is a mutagen?
an agent that causes a genetic mutation
what is the effect of a mutagen?
produces mutations in DNA, which can result in loss of function of a particular gene
what is a mutation?
- a change in the genetic material of a cell
- sequence of nucleotides in DNA is changed
what are mutagenic agents?
agents that damage DNA and can lead to permanent changes in the DNA
what is the process of inducing a mutation called?
mutagenesis
what is the result of mutagenesis?
induced mutations
what does carcinogenic refer to?
cancer-causing
what are the three main types of mutagens?
- chemical
- natural
- physical
what are chemical mutagens?
chemicals that cause mutations when exposed at high frequencies or for prolonged periods of time
what is the consequence of chemical mutagens in DNA?
causes a change in DNA that alters the function of proteins, making the cells impaired
what are two examples of chemical mutagens?
- ingested chemicals: alcohol
2. environmental irritants and poisons: asbestos
what are naturally occurring mutagens?
- mutations that spontaneously show up due to DNA replication error
- agents that are present at normal levels within natural environments
what are the two types of naturally occurring mutagens?
- biological mutagens
2. non-biological mutagens
what is an example of a non-biological naturally occurring mutagen?
mercury
what is are examples of biological naturally occurring mutagen?
viruses, bacteria, fungi
what are examples of physical mutagens?
heat, ionising radiation
what is radiation?
any transfer of energy through space from a source
what is an example of radiation?
electromagnetic radiation from the sun
why is ionising radiation so dangerous?
has enough energy to break chemical bonds in molecules, like DNA
what are the two main types of radiation that may cause mutation?
electromagnetic radiation, ultraviolet radiation
what are the types of mutation?
point, frameshift, chromosomal
what is a point mutation?
a change of a single nucleotide, thus resulting in a different amino acid
what is an example disease caused by a point mutation?
sickle cell anaemia
can a point mutation result in a frameshift mutation?
yes
how can a point mutation result in a frameshift mutation?
the insertion or deletion of a single nucleotide can shift the entire DNA sequence, therefore coding for a whole sequence of incorrect amino acids
what are the five criteria used in order to distinguish a certain type of mutation?
- origin
- amount of genetic material changed
- effect of the mutation on DNA
- effect of the mutation on phenotype
- heritability of mutations
how can a mutation’s origin help distinguish the type of mutation?
- spontaneous mutations : arise randomly due to errors during DNA replication
- induced mutations : arise as a result of an environmental agent
how can the amount of genetic material changed due to a mutation help distinguish the type of mutation?
- point mutations : changes to a single base pair on a single gene
- frameshift mutations : may affect a single gene or as a sequence of genes
how can the effect of the mutation on DNA help distinguish the type of mutation?
- substitution
- insertion
- deletion
how can the effect of the mutation on phenotype help distinguish the type of mutation?
- silent mutation : no change in phenotype
- could be harmful, neutral or beneficial
how can the heritability of the mutation help distinguish the type of mutation?
- somatic cell : non-reproductive cell
- germ-line cell : reproductive cell
what are the different types of changes to proteins due to point mutations?
- nonsense mutations
- missense mutations
- silent mutations
- neutral mutations
what are nonsense mutations?
- the accidental change in an amino acid to a stop codon
- cuts the protein short
what are missense mutations?
- point mutations that result in an amino acid change
- makes the protein less functional
what are silent mutations?
- changes that do not cause a change in type amino acid
- different codes that could translate into the same amino acid
what are neutral mutations?
- changes that result in an amino acid of the same type as the original
what are chromosomal mutations?
- large scale changes
- affects the overall structure of a chromosome or the entire number of chromosomes
what are the four types of chromosomal mutations?
- deletion
- insertion
- inversion
- translocation
what is a chromosomal deletion?
occurs when a section of DNA is removed and not replaced
what is the effect of chromosomal deletion?
results in a reduction in the number of genes in a chromosome
what is a chromosomal insertion?
occurs when a portion of DNA is duplicated and inserted
what is the effect of chromosomal insertion?
results in an increase of the number of genes on the chromosome
what is a chromosomal inversion?
occurs when a section of DNA is removed, flipped 180°, then reinserted (reversed base order)
what is the effect of chromosomal inversion?
can cause diseases such as haemophilia
what is chromosomal translocation?
occurs when a section of DNA is moved from one chromosome to another non-homologous chromosome
what is the effect of chromosomal translocation?
leads to gene fusions, where two normally separate genes are joined
what is aneuploidy?
occurs when one or more extra copies of a chromosome are made, or an entire missing chromosome
what is an example of aneuploidy?
down syndrome
- extra copy of chromosome 21
what are somatic mutations?
- occur in non-reproductive cells cells
- often due to an error before mitosis
- can both affect and not affect phenotype
- is not passed down
what are germline mutations?
- occurs in the sexual reproductive cells
- affects the gametes, which can be passed down
how do mutations in coding DNA segments affect an individual?
- affects the type or sequence in amino acids in a protein
- directly affects the protein, therefore the phenotype as well
how do new alleles arise from mutagens?
mutagens –> mutation –> physical change in DNA –> new allele
what is the DNA that has neither a protein-coding nor a regulatory function called?
junk DNA
what differentiates coding DNA from non-coding DNA?
non-coding DNA has so no protein end-product
how is non-coding DNA important?
- regulatory sequences that promote ‘switch on’ and ‘switch off’ genes
- code for things like rRNA
how do mutations that affect non-coding DNA affect the individual?
mutations in non-coding genes are linked to developmental and congenital abnormalities
how do mutations that affect non-coding DNA in germline cells affect the individual?
- can lead to a miscarriage
- congenital abnormalities
what are the factors that contribute to genetic variation?
fertilisation, meiosis and mutation
how does little to no variability in a population make them more easily extinguishable?
- static and unchanging population
- less likely to adapt to sudden changes in environment
what factors increase genetic variability through the recombination of genetic material?
meiosis and fertilisation
what factor increases genetic variability by increasing the number of alleles for a trait?
mutation
what is crossing over, random segregation and independent assortment a part of?
meiosis
what occurs during the non-disjunction of chromosomes in meiosis?
homologous chromosomes fail to segregate during meiosis I, leading to only two out of the four daughter cells
what are the factors that cause changes in allele frequency within a population?
- selective pressure
- sexual selection
- mutation
- genetic drift
- gene flow
how does selective pressure cause changes in allele frequency in a population?
- variations
- allows for individuals well suited for the envrionment increase
how does sexual selection cause changes in allele frequency in a population?
the most successful mater’s genes remain in the gene pool
how does mutation cause changes in allele frequency in a population?
- leads to the formation of new alleles
- can be either bad or good
how does genetic drift cause changes in allele frequency in a population?
- random chance
- may be due to natural disasters/isolated individuals
how does gene flow cause changes in allele frequency in a population?
mixing of new individuals in a population
what is the bottleneck effect in genetic drift?
genetic drift as a result of a natural disaster, where the population drastically decreases
what is the founder effect in genetic drift?
few individuals in a population becoming geographically isolated from the original population
what is the effect of selective pressure on the next generation?
alleles that make individuals more suited increase
what is the effect of sexual selection on the next generation?
alleles of more successful maters are more ocmmon
what is the effect of mutation on the next generation?
new beneficial alleles become more frequent
what is the effect of genetic drift on the next generation?
causes individuals within a population to be different (not necessarily better)
what is the effect of gene flow on the next generation?
allele frequency in the population changes
what are the three main uses of biotechnology?
industrial, agricultural, medical
what are the general applications of biotechnology in the industry?
- pollution prevention
- biomaterial production
- biofabrication
- synthetic biology
what are the general applications of biotechnology in agriculture?
- reproductive technologies for selective breeding
- GMO’s
what are the general applications of biotechnology in the medical field?
- gene therapy
- human IVF
what is bioethics?
the application of ethic to the science and practice of biology
what is a solution to food shortages?
GMO’s
what is an example of future directions and benefits of biotechnology research?
CRISPR
what is CRISPR?
- new genome editing technique
- an enzyme that can snip DNA at a particular base and attach to a ‘guide’ RNA
- genes can now be spliced and inserted with pinpoint accuracy
what is an implication of CRISPR?
- brings about concerns around germ-line gene editing
- creation of designer babies
what are some of the future directions of biotechnology research?
- gene therapy
- GMO’s to alleviate hunger
- plant banks and animal cryopreservation to maintain biodiversity
- plant/algae based resources for biofuels
how has the Earth’s biodiversity changed due to biotechnology?
biotechnology in breeding programs can counteract loss of biodiversity
what are some ancient techniques of biotechnology?
- food production : bread, cheese, wine
- medicine
- crop and animal domestication
what are some past (classical) techniques of biotechnology?
- fermentation
- plant and animal selective breeding
- agriculture
- medicine and antibiotics
what are some modern techniques of biotechnology?
- DNA splicing
- DNA amplification
- recombining DNA
what are some potential benefits of biotechnology?
- gene therapy to treat human disease
- GMO’s to alleviate hunger
what is the short-term effect of biotechnology on Earth?
increase biodiversity by introducing new gene combinations
what is the long-term effect of biotechnology on Earth?
decrease biodiversity by selectively breeding desired genes
what are the five criteria in biotechnology ethics?
- making an ethical decision
- benefit and non-harm
- individual rights and autonomy
- equity and justice
- privacy and societal perception
what is selective breeding?
involves mating a male that displays a desirable characteristic with a female with a desirable characteristic to pass it down to offspring
what is artificial insemination?
collecting the sperm from a chosen male and artificially introducing it into several females
what is in vitro fertilisation?
- an egg is artificially inseminated outside of the mother’s body
- zygotes are cultured until they have progressed to an early stage of development
what is artificial pollination?
removing the stamen of a flower and dusting pollen into the stigma
what are the advantages of selective breeding?
the offspring may acquire both favourable characteristics from both parents
what are the advantages of artificial insemination?
- sperm can be collected and stored
- doesn’t require any mating
what are the advantages of in vitro fertilisation?
- decreases chance of miscarriages
- used in cases where there is decreased fertility
what are the advantages of artificial pollination?
produces large numbers of plants and seeds
what are the disadvantages of selective breeding?
- can be expensive to transport animals
- may end up not mating
- time consuming
what are the disadvantages of artificial insemination?
- can be costly due to requirement of specialised equipment
- time consuming
- reduction of genetic diversity
what are the disadvantages of in vitro fertilisation?
- may be difficult to retrieve the eggs
- very expensive
- reduces diversity of populations
- genes of infertility may be passed down
- sperm banks can alter the genetic composition
what are the disadvantages of artificial pollination?
- reduces genetic diversity
- increase in genetic uniformity
what is the main purpose of reproductive technologies?
to pass on desirable traits to the next generation
what is gene cloning?
when a gene to removed from a source to be put into the DNA of another organism, to make identical copies of that gene
what are the four steps in gene cloning?
- gene is cut from source by restriction enzymes
- gene is pasted into a vector DNA
- vector DNA is introduced to a host cell (transformation)
- host cell makes copies
define polymerase chain reaction in terms of gene cloning.
- a form of in vitro DNA cloning
- amplifies a particular DNA sequence
- makes many copies to be analysed
what are the three processes in PCR?
- denaturing - DNA strand separates
- annealing - bases are matched
- extension - all connects together
what is whole-organism cloning?
where the entire DNA of an organism is cloned to make an identical clone
what is whole-organism cloning used for?
used to create a genetically identical whole organism
who was the first organism to undergo whole-organism cloning?
Dolly, the sheep
what is another name for whole-organism cloning?
somatic cell nuclear transfer (SCNT)
how many animals are involved during whole-organism cloning?
four
what are the three animals involved in somatic cell nuclear transfer?
- nucleus donator
- egg donor
- surrogate mother
- genetically identical organism born
what were the steps taken in order to perform whole-organism cloning for Dolly?
- cells were taken from the udder of the nucleus donator
- nucleus was removed from a healthy unfertilised egg from the egg donor (enucleation)
- nucleus from sheep 1 was injected into the egg of sheep 2
- the born sheep is now genetically identical to sheep 1
what is a disadvantage of cloning?
all members of the cloned population are genetically identical –> susceptible to changes in environment
what is the aim of recombinant DNA technologies?
to insert a gene from one species into the genome of another
what are the steps in the recombinant DNA technology process?
- required gene is isolated from a cell
- plasmid is removed
- plasmid is cut by a restriction enzyme
- DNA is cut by the same restriction enzyme (matching sticky ends)
- sticky ends of both plasmid and DNA join
- DNA fragments are joined by an enzyme called ligase
- plasmid is inserted back
- many copies are made of the new gene
- inserted into egg cell
what are transgenic species?
a species that has been created by moving a gene across species
what are examples of transgenic species?
- bt cotton
- salmon strawberries
what are examples of transgenic species?
- bt cotton
- salmon strawberries
what is micro-injection in gene delivery?
injection of DNA directly into the nucleus of a single cell
what is biolistics in gene delivery?
mechanically delivering DNA into target tissues with gene guns
what is electroporation in gene delivery?
increasing the membrane permeability through electricity
what is transduction in gene delivery?
DNA is carried into cell through a viral vector (can be through blood or aerosol delivery)
what two fields are transgenic species useful in?
agriculture and medicine
why is bt cotton benficial?
- codes for a natural pesticide (protein) that kills caterpillars
- reduces the need for harmful pesticides
- reduces the development of pesticide resistance in caterpillars
- is not harmful to humans
why are transgenic species beneficial?
increasing genetic diversity (short term)
what is a con of transgenic species?
over time, genetic diversity is reduced
how are transgenic species beneficial in the medical field?
provides the opportunity to safely test and develop new treatments
what are some of the benefits of genetic technologies to society?
- improved food quality
- cost-effective production
- improved food supply
what are some benefits of genetic technologies in agriculture?
- produces crops and animal varieties that are better suited to specific environments
- increases the productivity of bad land
- increased nutrition in crops
what are some benefits of genetic technologies in medicine?
- provides the opportunity to produce valuable products
- can help individualise treatments
- vaccines!
what are some benefits of genetic technologies in the industry?
- promises genetically engineering plants and bacteria that can absorb heavy metals
- aid in remediation of mine sites and heavily polluted areas
what are the long term and short term effects of genetic techniques?
short term : increase biodiversity
long term : reduce biodiversity
what are the three impacts that influence the development of biotechnologies?
social, economic and cultural
what do social impacts involve?
- human rights
- benefits to humans
- sustainability of resources
what do economic imp- acts involve?
- financial costs
- financial benefits
what so cultural impacts involve?
- religious opinions
- difference in opinion due to location and customs
what is an economic concern in using biotechnology?
- small farmers may not be able to afford expensive GMO’s (disadvantaged)
- tech could be patented, giving big corporations monopoly
what are some ethical issues surrounding cloning?
- animal welfare
- legal concerns
- alters genetic composition
- cost and access
- moral and religious issues
- health risks
What are some social/ethical implications of biotechnology?
- Equity access issues
- Displacement of traditional lifestyles
- Potential Bioterrorism
- Animal cruelty concerns
- Loss of consumer understanding of what is in their food
