HSC Biology Module 6

How do mutations occur?

1. spontaneous mutations: e.g. naturally occurring electromagnetic radiation from sun causes cancer

2. induced mutations: e.g. artificially electromagnetic radiation

where do mutations occur?

1. germine mutation

2. somatic mutation

what are the types of mutations?

1. chromosome mutation

2. chromosome abnormalities

3. point mutation

4. substitutions

5. frame shift

What is a Mutagen?

A chemical or physical agent that interacts with DNA and causes a mutation.

Carcinogenic mutagens

causing mutations that result in cancer

What are the DNA repair mechanisms?

1. base excision repair

2. nucleotide excision repair

3. mismatch repair

4. double stranded break repair

what are the three mutagens?

1. physical e.g. electromagnetic radiation

2. chemical e.g. x rays

3. naturally occurring e.g. virus in host cells

electromagnetic radiation

transmitted through waves e..g UV radiation acts as mutagen casing 2 adjacent base pairs to form covalent bonds causing dimer structure

5 ways mutations classified

1. DNA affected (gene or chromosome)

2. arise (spontaneous or induced)

3. change DNA structure (point, frameshift, deletions, insertions, translocations)

4. DNA functioning and proteins (nonsense, missence, neutral, silent)

point mutation

gene mutation in which a single base pair in DNA has been changed

1. substitution

2. frameshift

Subsitution mutation

1 base is change for a different base e.g. sickle cella Anaemia

1. missense: change in amino acid

2. non sense: stop codon

3. silent/neutral: sam amino acid

frameshift mutation

mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide

1. insertion

2. deletion

gene mutation

a change in the base sequence of a gene

chromosomal mutation

A change in the chromosome structure, resulting in new gene combinations

chromosomal deletion

A mutation involving the loss of a section of a chromosome

chromosomal duplication

A mutation involving the duplication of a section of a chromosome

chromosomal inversion

When part of the chromosome becomes oriented in the reverse of its usual direction

chromosomal insertion

section breaks off and attaches to different chromosome which lowers genetic variation

chromosomal translocation

When part of one chromosome breaks off and attaches to another non homologous, chromosome.

Aneuploidy

Abnormal number of chromosomes.

example of aneuploidy

Down syndrome (trisomy 21) extra copy of chromosome 21

karyotype chromosomal diagnosis

describes abnormality and if there is a disability

somatic and germline mutations

1. somatic: most mutations not inherited

2. germline: in gonads producing gametes and mutation inherited

effect of somatic mutation

1. no effect

2. cell dies

3. becomes cancerous

effect of germline mutation

1. no gamete involved means no effect

2. gametes involved new inheritance mutation

what are examples of non coding DNA (introns)

telomeres: protect chromosome deterioration

chromosomal errors

crossing over fails and chromosomal aberrations may be introduced

e.g. inverted

what are changes in chromosomal numbers (non-disjunction)?

when sister chromatids do not separate correctly e.g. Down syndrome

difference in mutation, variation, variability

mutation: unusual error

variation: difference in characteristics

variability: different forms of gene in population

selective pressure

when the environment pushes an individual or population to adapt or evolve

sexual selection

when individuals select mates based on heritable traits

mutation

formation of new alleles

genetic drift

A change in the allele frequency of a population as a result of chance events rather than natural selection.

founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population e.g. colonisation

bottle neck effect

A change in allele frequency following a dramatic reduction in the size of a population

gene flow (migration)

movement of alleles from one population to another e.g. immigration

Biotechnology

A form of technology that uses living organisms, usually genes, to modify products, to make or modify plants and animals, or to develop other microorganisms for specific purposes.

ancient biotechnology

1. farming and selective breeding

2. crossbreeding

3. food production (cheese and bread)

4. fermentation (alcohol )

5. medicine (plants and herbs)

Modern Biotechnology

1. DNA splicing (restriction enzymes splice bases)

2. DNA amplification (polymerise chain reaction tor replicate)

3. recombine DNA (DNA ligase joins fragments)

social and ethical implications

agriculture(GM): GM organisms, habitat destruction

industrial (anthrax): bioterrorism, increased defence

medical (insulin): labelling, animal welfare

biological control

the intentional release of a natural enemy to attack a pest population

Bioterrorism

the deliberate spread of pathogenic organisms into a community to cause widespread illness

BIOTECHNOLOGY monoclonal antibodies

a collection of identical antibodies that interact with a single antigen site

examples of gene technology

1. gene silencing

2. marker assisted breeding (desirable traits)

3. CRISPR-Cas9 (restriction nuclease to regulate genes)

why is biotechnology limited?

1. financial positions

2. lifestyle

3. social profile

example of biotechnology for greater good

1. recombinant DNA for BT Cotton

2. genetically modified organisms for golden rice

what is golden rice

GM rice crop enhanced with Vitamin A

POSITIVE: more nutritional value and vitamins kore accessible

NEGATIVE: increased retail price, adding new genes to gene pool

difference between traditional and bio fortification

fortification: nutrients added while processing

bio fortification: breeding crops with added nutritional value e.g. golden rice

social implications of biotechnology

1. privacy (DNA profiling stores information)

2. health (GM have different ingredients)

3. societies views (damage environment)

4. social equality, access, cost (golden rice)

ethical implications of biotechnology

1. legal implications (who should know of genetic disorders)

2. medical intervention and consent (pregnant woman of disorder that can't be treated)

3. philosophical, cultural and religion (acting as God)

4. animal welfare (transgenic pigs impact joints)

loss of biodiversity

overtime reduced increase in biotechnology

conservation biology

short term new gene means more variation

uses of biotechnology

1. agriculture (Bt Cotton)

2. industrial (bacteria to decrease toxic waste)

3. medical (knockout mice to model diseases like cancer)

Bioremediation

The use of living organisms to detoxify and restore polluted and degraded ecosystems

Biosensors

Microbes that can locate biologically active pollutants

Biopharming

Use of genetically engineered animals to act as biofactories for producing drugs, vaccines, antibodies, hormones, industrial chemicals such as plastics and detergents, and human body organs.

Xenotransplantation

A transplantation of an organ, tissue, or cells between two different species.

future use of biotechnology

e.g. coral reefs

reduce devastation on coral reeds by global warming, increase water temp and bleaching

'super coral' though selectively breeding coral, investigating genomes and insert genes from heat resistant corals through CRISPR-Cas9

reproductive technologies

1. selective breeding

2. artificial insemination

3. artificial pollination

4. cloning

5. IVF

6. transgenic species

7. whole organism breeding

8. recombinant DNA

artificial insemination

a process of fertilisation in which a man's sperm is placed directly into a woman's vagina e.g. sport horses

POSITIVE: cost effective, transport, reduce mating

NEGATIVE: one father

artificial pollination

process of cross pollination in which pollen collected from one plant is manually transferred to the stigma of a second plant

POSITIVE: breeder control

NEGATIVE: not exact in determining genes

IVF (in vitro fertilisation)

creating an embryo (joining a sperm and an ovum/ova) outside of a human body in Petri dish

POSITIVE: treat fertility issues

NEGATIVE: religious issues (acting as God)

whole organism cloning

Creating a whole new organism using the DNA of an already existing individual

gene cloning

the production of multiple copies of a single gene

therapeutic cloning

the use of SCNT to produce human embryos for research purposes

polymerase chain reaction (PCR)

A technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules, and nucleotides.

1. denaturing

2. annealing

3. extension

Recombinant DNA technology

technology that combines genes from different sources into a single DNA molecule

e.g. transgenic organism

Transgenic Organism (GMO)

genetically modified organism; any organism that contains genes from other organisms

three examples of transgenic species

1. knockout mice (stem cells)

2. hepatitis B vaccine (recombinant DNA)

3. pig organs (xenotransplantation)

Process of Recombinant DNA

1. gene isolated

2. DNA fragments joined by ligase

3. plasmid inserted back into cell copies produced

4. gene inserted into another species

Recombinant DNA

insulin

restriction enzymes

Enzyme that cuts DNA at a specific sequence of nucleotides

Vector

same self replicating DNA fragment e.g. E coli

gene delivery techniques

inserting desired gene into genome of a species

1. microinjection

2. biolisitcs

3. electroporation

4. transaction by viral vector

Bt cotton

contains a gene that enables the plant to produce its own pest-killing toxin e.g. caterpillar

knockout mice

-gene is intentionally deleted (knocked out)

- used to study human diseases

hepititis B vaccine

Recombinant DNA

how does xenotransplantation work?

organs from transgenic swine have complementary surface markers that inhibit activation of organ

gene therapy

The insertion of working copies of a gene into the cells of a person with a genetic disorder in an attempt to correct the disorder

Charles Darwin, Origin of Species

Presented the theory of evolution, which proposed that creation was an ongoing process in which mutation and natural selection constantly give rise to new species. Sparked a long-running religious debate over the issue of creation.

SNP (single nucleotide polymorphism)

a single base-pair site where variation is found in at least 1% of the population