trials study Flashcards
what is homeostasis?
maintaining relatively stable internal conditions within the body
what is the average temp of human body?
37 degrees
process of punctuated equilibrium?
fluctuating rates of evolution–> marked by periods
feedback mechanism
heat: stimulus–> receptor–> control centre (hypothalamus) –> effector (shivering, sweating) –> temp decrease/increase
first line defence barrier:
skin, mucus
how does punctuated equilibrium differ from Darwin’s process?
occurring intermittently, not a gradual change (sometimes rapid or slow periods)
what did Sutton, Boveri and Morgan do?
Morgan: fruit flies –> sex-linked chromosomes, eye colour on X/Y chromosome
Sutton: grasshopper–> random assortment of genes in meiosis
Boveri: urchin –> meiosis, complete set of chromosomes for normal growth, genes on chromosomes
watson and crick?
DNA shape–> double helix and nitrogenous bases
which pathogen is used to transfer desirable gene?
bacteria share their plasmids
transgenic species?
DNA from certain organism is inserted into another organism for certain desirable trait
natural selection eg:
antibiotic resistance: bacteria
insects develop resistance to DDT
artificial selection:
cows getting bigger
process to produce transgenic species eg:
- The desirable gene coding for bovine growth hormone is identified on the chromosome and remove using specialised restriction enzymes.
- Regulatory promoter sequences are added which allow the isolated gene to function and be expressed.
- Multiple copies of the gene are made using polymerase chain reaction (PCR) technique. Alternatively you can clone using a bacterial plasmid.
- The gene is inserted into the egg cell of the salmon using microinjection, a gene gun or viral vector.
- The gene for BGH is expressed in the salmon offspring.
characteristics of a: prion
- smallest pathogen, protein which causes disease, non living and don’t have DNA
- infect by distorting shape of healthy protein
- usually found in brain
characteristics of a: virus
- non/living
- DNA encased in protein
- non cellular
- very small, must reproduce by hijacking host cell and injecting its DNA
characteristics of a: fungus
- both uni/multi-celled eukaryotes
- have cell wall/membrane
- tiny: yeast to large:mushrooms
- reproduces by spores, a/sexual reproduction
characteristics of a: bacteria
- single-celled prokaryote
- have cell wall too
- binary fission and asexual reproduction
characteristics of a: macroparasite
- seen with naked eye
- multicelled Eurkaryotic
- ENDOparisite: living inside the body
- ECTOparasite: external, suck blood
- may be vector too
eg. and method of contraction/ treatment: fungus
thrush, tinea, mould,ringworm
contract by: contact, contaminated water
treat: antifungal medicine/creams