Resting potential
Question: and sir, i have checked and found that u gave the answer as the outside of the membrane becomes less positive, whilst u said that the answer is more positive..so, which answer do we take? i am referring to nyjc prelims 04 mcq question 39:To simplify things:
At resting state, the potential in the axon is less than the external environment (-70mV). This resting potential is due to the ATP pump pumping in 2 potassium ions in and 3 sodium ions out (net charged particles going out is more than those coming in).
When the pump is not working, there will be no entry of potassium in and no sodium out. Thus there will be a net decrease in charge outside due to the stopping of transporting 3 charged sodium out. Thus the environment outside will be lesser than previously (less positive) compared to the internal environment.
PS: Ignore the previous explanation of potassium diffusion, not required in this sense.
MG
posted by MG-Biology @ 4:51 PM
8 Comments:
sir, could you please explain random segregation. I'm still not too sure what it means.
mr goh,
i haf three qn to raise.
the first qn is regarding animal trpst.
how does a high-salt content diet leads to coronary heart disease exactly? i read this note that u gave us right. it mention smthg bt salt lowering the water potential of blood [w/ means vol decrease?] and therefore cause an increase in blood pressure. while in the lect. notes, it's been taght to us that it's the increase in blood volume that leads to increase in blood pressure. arent these two pieces of info contradictin themselves?
__________________________________
the second qn regarding solute potential. is osmotic pressure = solute potential?
___________________________________
and the last reg. photosynthesis.
it is said that in calvin cycle. carbon dioxide is reduced. in wud sense is it reduced? a loss oF electrons? or gain in hydrogen
___________________________________
is transport of carbon dioxide anD components of blood in our syllabus. it is not req. acc. to the syllabus given in TYS.
thanks.
*chunying
mr goh..
wuD exactly is the format of the bio paper? cus the syllabus given in TYS is 9284 anD our syllabus is 9283.
*chunying
Vinesh:
Random segregation refers to the splitting of alleles through the movement of paternal and maternal chromosome to two opposite poles.
As there are 23 pairs, each separation will be random.
Chun ying:
(i) The first question i would like to see the two sources and compare.
(ii)Please refer to definitions of terms in textbooks
Osmotic Pressure: Pressure generated by the osmotic flow of water through a semi-permeable membrane into an aqueous compartment containing solute at a higher concentration.
Solute Potential: The potential inside a cell membrane measured relative to the fluid just outside
see the difference?
(iii) "It is said", please show me the source...
(iv) Transport of carbon dioxide - yes, components of blood, basics.
Format is exactly what is in the TYS
To add on, the diff between 9284 and 9283 is the SPA component replacing the practical test.
sir, since the notes contain little information on the general information of plathyhelminths, are we supposed to study one case example?
and sir, with regards to random segregation, based on the answer you gave, what then is the difference between independant assortment and random segregation?
Post a Comment
<< Home