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unit 5 bio flashcards
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- 1factors which might increase the frequency at which a mutation in a gene occurs• high energy radiation (e.g. X-rays)
• chemical mutagens (e.g. benzene, cigarette smoke, mustard gas)
• length of time of exposure to a mutagen
• dosage of mutagen - 2Reasons for using a virus to transfer genes into cellstargets cells and replicates in cells
- 3how do you make radioactively labelled fragments visible following electrophoresis?transfer to a nylon membrane, then use autoradiography
- 4how are stem cells able to develop into different types of cell?• different genes are switched on/off
• different enzymes/proteins produced
• determined by hormones in its environment - 5why would you see an object in you peripheral view in low visual acuity?• Higher density of rod cells in periphery, cones concentrated in fovea
• Many rod cells connect to one bipolar cell, many of which connect to one ganglion cells
• Rod cells send few impulses per unit area of retina - 6why is evaporation of sweat from the skin effective in reducing body temperature?• sweat evaporates from skin which requires much heat energy
• this cools the blood - 7why are males more likely to have a disease carried on sex chromosome?• males are XY, females are XX
• Y chromosome is shorter so often has no equivalent
• males only need to inherit one recessive allele to have the disease - 8role of calcium ions in muscle contrations• calcium ions bind to troponin and cause tropomyosin to twist and reveal binding site on actin
• activate ATPase- ATP needed to break and form cross bridges, and move myosin head - 9why use bacteria in genetic engineering?• Easy to insert genes into bacteria; using a plasmid as a vector
• Bacteria reproduce rapidly; so many copies of the target gene are produced
• Bacteria can be grown on a large scale;
so lots of the target protein can be produced - 10why injected plasmids with target gene into fertilised eggs instead of adults?• embryo divides by mitosis
• gene will be present in all cells of the organism
• the gene gets passed to future generations - 11role of phosphates• ATP – energy source
• Phospholipids – membranes
• DNA /RNA – e.g. protein synthesis
• NADP – photosynthesis - 12arguments against giving reproductive hormones to pigs• hormones may be present in meat and ingested by humans- may affect female menstral cycle/ have unknown effects
- 13why might 2 primers be needed in PCR?because the sequences at the ends of the target sequence are different- allows both strands to be copied
- 14All or nothing principal• All action potentials are the same size
• There is a threshold value that must be exceeded in order for action potential to occur - 15role of a vector?transfer genes from one organism to another
- 16how to antibodies work?bind to antigens on pathogen, causing agglutination which makes it easier for the phagocyte to engulf the pathogen
- 17what is a clone?A group of genetically identical cells or organisms
- 18what is an oncogene?A gene that stimulates cell division; produced by mutation of a proto-oncogene
- 19what are stem cells?cells that can...
divide and renew themselves over long periods
are unspecialised
can develop into other specialised cell types - 20advantages and disadvantages of using embryonic stem cells in organ transplants• easier to find (e.g. lots available from IVF), easier to grow, and are pluripotent
• might be rejected by immune response of recipient - 21why use yeast rather than bacteria to produce human proteins?Yeast is eukaryote and it is able to remove introns but bacteria are not
- 22why insert pesticide resistance genes into chloroplasts DNA instead of the plant's chromosomes?Pollination is a potential source of transfer of genes between plants. As pollen grains do not contain chloroplasts, pollen transferred from transgenic plants to non-transgenic plants does not contain foreign genes
- 23difference between RFLPs and STRs?The basic unit of a RFLP is longer
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- Fichas sobre unit 5 bio flashcards, creado por joannalivesey el 26/05/2014.
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