IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: Sue T on May 25, 2010, 02:06:46 pm
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the question s attached (n08 q26)
i get tht th point must be on the curve AD (low CO2) not CB (high CO2)-- but y is the ans D?
isnt the muscle resting? y would it need oxygen???!
and q 36 -th ans is D but- what does glabal warming have 2 do wth malaria???!!!
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the question s attached (n08 q26)
i get tht th point must be on the curve AD (low CO2) not CB (high CO2)-- but y is the ans D?
isnt the muscle resting? y would it need oxygen???!
and q 36 -th ans is D but- what does glabal warming have 2 do wth malaria???!!!
ok so if a muscle is resting, then the oxygen dissociation curve would be higher ( the AD one ), if its excersicing the its the lower one as oxygen needs to be released fast ( for respiration in the muscle )
the muscle is resting, but it needs to respire ( its like me telling you, why do u breathe when ur sleeping, lol ). its usually because in the viens in the parts of ur body ( they are usually next to the muscles, ans so the muscles contract, causing the blood to go back to the heart against gravity )
q36: 1st and 3rd are difinantely correct, the 2nd option ( about global warming ), maintains the optimum temperature at which these mosqitos grow, so its correct
hope this helped.. :)
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thank u
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thank u
anytime :)
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Which is characteristic of phloem sieve tubes?
solute potential of
the cell content: high or low?
the ans is low but y low? isnt phloem sap filled wth sucrose n aminos?
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Which is characteristic of phloem sieve tubes?
solute potential of
the cell content: high or low?
the ans is low but y low? isnt phloem sap filled wth sucrose n aminos?
yea its low because its not askin about the concentration of solutes in the phloem seive tube
its asking about solute potential, whcih decreases if there is an increased amount of amino acids or sucrose dissolved in it!
hope this helped ;)
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nov08/q18..shuldn't it b C?
why is de ans A?
plz help me
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nov08/q18..shuldn't it b C?
why is de ans A?
plz help me
ok so if substance X replaces telomere ( they are specialized DNA-protein complexes that cap the ends of the chromosomes. Their function is to help with replication of genetic material when cells divide and to protect the ends of the chromosome ends from degradation ).
so telomeres promote cell division and are then removed, soo the cell will keep on dividing!!
so with substance X : cell will divide continually
and without substance X : cell division eventually slows and stops ( cuz telomeres are now NOT being completley replaced, so at first they slow down cell division and then stop )
hope this helped .. :)
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thx :) n can u also plz explain june07/q4???
thx alot :)
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thx :) n can u also plz explain june07/q4???
thx alot :)
ok so from the top part of the question :
1 unit on stage = 100 on ocular graticule
so measure any of the pollen grains "at start" and "after 4 hours" then subtract ( after 4 hours - at start = about 5 units)
so 5x1/ 100 = 0.05
multiply the value by 100 to change it from ( 0.1 mm to micrometers) and you will get 5
hope this helped :)
iim not actually sure if its the right method, but thats how i got my answer :S