(Original post by Picture~Perfect)
I'm going to attempt an unofficial mark scheme, but I'll need your help
Thanks to JimmyK, ChocolatePearl and sydney07 for your help
(a) (i) TGCTAC (ii) UGC
(c) It could change the shape of the toxin molecule
(d) Since acetylcholinesterase is inhibited; the acetylcholine diffuses across synaptic cleft, and binds to receptors, triggering an action potential, since no acetylcholinesterase is released the acetylcholine is not broken down; action potentials are continually given off; muscles controlling breathing continually contract; hence can't breath
(a) (i) Shortens (ii) Stays the same
(c) Myosin head are bound to a molecule of ATP, during contraction this is hydrolysed releasing a large amount of energy. Myosin bind to actin forming cross-bridges and uses the energy to move, pulling along the actin. When the myosin heads detach form the actin another molecule of ATP binds to them. For a strong contraction this action is repeated. If insufficient ATP is provided, this process can not continue, resulting in weaker contractions.
(i) A short time after the concentration of oestrogen begins to rise, the contraction of LH rises
(ii) There is a fall in the concentrate of progesterone at the end of her cycle
(i) Progesterone uses negative feedback to inhibit the production of FSH
FSH stimulates the growth of follicles which produce eggs. If the follicles do not grow then eggs are not produced and released. Eggs are never produced as progesterone is continually released. If there is no egg it cannot be fertilised.
(ii) Progesterone is released automatically.
(a) Increased intensity of exercise leads to increased respiration which results in an increase in the concentration of carbon dioxide in the blood. This is detected by chemoreceptors in the aortic arch and carotid bodies. These send nervous impulses to the cardioregulatory accelerator centre in the medulla oblongata. This sends impulses to the SAN centre via the sympathetic nervous system. The SAN stimulates and increase in heart rate.
(b) (i) To act as a control, to allow comparison
(ii) Error bars don't overlap so the results are not due to change (less than 0.05)
All the results of the change in mean heart rate are negative numbers.
Quantitative analysis (numbers mentioned?)
(a) Restriction endonuclease
(b) (i) (ii)
(c) (i) Immune system detects it being foreign and attacks it?
(ii) So the process is adjusted accordingly and mistakes are not repeated again/same mistake avoided occurring twice.
(iii) Artificial Gene only needs to be inserted once/no other __necessary
Artificial Gene work for a long time
Only tried on rats, may pose dangers in Humans
Long term side-affects of Artificial Gene not known
(c) (i) (ii)
(a) (i) (ii)
(b) (i) (ii) (iii)
(a) ((22.9-18)/22.9)*100 = 21.4%
(i) To allow for perspiration/panting. Water evapourating from skin/mouth allows heat to leave the blood by convection and the core body temperature to fall.
(ii) Food intake increases because metabolic rate increases. Increased respiration produces more heat to increase body temperature, and this requires increased amounts of food/glucose/substrate.
(c) Milk production decreases because metabolic rate/respiration decreases so less ATP is available for secreting milk or synthesising milk proteins.
(d) Skin is exposed to environmental conditions, heat will be lost by conduction/convection/radiation. Rectal temperature more accurate because more insulated.
(e) A Bull is chosen with a relatively low core body temperature/ that doesn't suffer from Heat Stress
(f) Countries have different numbers of people so using percentages allows for comparison between countries
(g) Sorry to any lactose intolerant people :P In past dairy was very small part of diet so not producing much lactase wasn't an issue. Today due to transportation and refridgeration lactase makes up a much larger proportion of our diet. Therefore people who are lactose intolerant are at an evolutionary disadvantage because if they eat dairy products they become ill. Perhaps they do not have as many children or may be more likely to die as a child, so over time a larger proportion of genes passed on will be from lactose tolerant people and more of the population will become so. This is directional selection. This will happen faster in a country that eats more dairy products because lactose intolerant people will be at more of a disadvantage.