How would you create lots of insulin?
- bacteria have short bits of DNA called plasmids- extract and cut using a restriction enzyme
- isolate the human insulin gene and cut using a resitrction enzymes
- stick plasmid and dna together using DNA ligase
- use the plasmid as a vector to get into bacteria, thus inserting the DNA into the bacteria
- put bacteria in fermenter w optimum conditions to replicate, to be harvester
How do you clone animals via embryo splitting?
- sperm taken from one animal to artificially inseminate another
- zygote forms and develops into early embryo
- this is split and put into uterus of surrogate mothers
- when animals are born they are clones of each other
How does reproductive cloning work?
- take a mature cell and isolate the nucleus
- take an egg cell and remove the nucleus
- join the two together with an electric shock
- mitosis produces embryo
- embryo put in a surrogate mother
- baby born is clone of the animal the nucleus was taken from
What does transgenic mean?
Transfer of genetic material from one species to a different species
What are reasons for and against cloning?
For: •animals can be given gene to produce large quantities of human antibodies rather than waiting for human itself to find correct antibody and replicate it
• animals could be made w organs similar enough to human ones to transplant ∴ no shortages
• prevents extinction
Against: • lack of variation
• inbreeding
• population issues
What are reasons for and against GM plants for food?
For: • can have desired characteristics
• can be made for specific environments
• better yield
• more resistant to pests ∴ you can use one broad range herbicide rather than several smaller ones
Against: • not scientifically proven safe for consumption, e.g. Some people report side effects like allergies and infertility
• if herbicide resistant but escapes and grows in wild, hard to destroy
What is the difference between sexual and asexual reproduction?
Asexual: one parent, parents and children genetically identical, faster, requires less energy, no partner needed, in bacteria, protoctista, fungi, plants, some animals
Sexual: two parents, offspring not genetically identical to parents/each other, produces variety, in fungi, plants, animals
How do runners asexually reproduce?
Overground aerial plants grow roots and develop into new plants
E.g. Wild strawberries
How does micropropagation work?
- small pieces (exoplants) cut from stems or side shoots of plant
- placed in agar growth medium, containing nutrients, minerals, plant hormones, and growth regulators
- when roots grow transferred to greenhouse
- put in pots w conditions like temp and humidity controlled
- small plants are clones
What are some of the benefits of micropropagation?
Quicker than seeds
Genetically identical to parent plant
Any time of year
What is a gene?
Section of a molecule of DNA
Where are chromosomes found?
In the nucleus
How many chromosomes do we have?
Diploid (2 sets of chromosomes, normal cells): 46
Haploid (1 set of chromosomes, sex cells): 23
What is the structure of DNA?
Two strands coiled to form double helix
A with T and C with G
What do dominant and recessive mean?
Dominant- only 1 copy necessary for characteristic to be shown
Recessive- 2 copies necessary for characteristic to be shown
What is codominance?
Both alleles contribute to phenotype ∴ both characteristics are shown
What is a homologous chromosome?
A set of chromosomes (1 maternal, 1 paternal) with the same type of gene, e.g. Earlobe shape
What is the difference between meiosis and mitosis?
Meiosis: to make gametes, in testes and ovaries, 2 rounds of cell division, 4 cells made, chromosome number decreases, cells not identical
Mitosis: for growth and repair, in all body cels, 1 runs of cell division, 2 cells made, chromosome number stays te same, cells identical
What can cause genetic variation?
- mutations
- random fertilisation between any egg and sperm
- crossing over and random assortment
What is a mutation? What are they caused by?
Rare random change in genetic material that can be inherited. Most harmful, some neutral, a few beneficial Caused by mutagens: -ionising radiation(UV, gamma) -chemicals(tobacco smoke) -viruses(HIV) -errors in cell division
Why do some people have multiple copies of a chromosome?
- failure to separate
- normal egg fertilised by abnormal sperm
What is cystic fibrosis?
Recessive
Persistent coughing, wheezing, breathing difficulties
What is haemophilia?
Recessive
Main affects males as on x gene
Prolonged bleeding
What is sickle cell anaemia?
Co-dominant
Pain due to sickle cells crisis(abnormal RBCs block small blood vessels), fatigue, heart palpitations, resistance to malaria
