AS Biology P1 MCQs Preparation Thread

[Jinosupreme]

sugar phosphate bonds never break
free nucleotide are used in dna replication ithink
since there are 2 chains so i think first it unzips(thats one time)then bonds form between mrna and dna(thats 1 time formation of completnery bases)
then thos break between mrna and base(thats second time bond broken) and then formation of bonds with dna complemetry second strand (iguess overall 4 times

Omg, thank you so much!!! appreciate ur help!

 

[zackle09]

http://papers.xtremepapers.com/CIE/...and AS Level/Biology (9700)/9700_w02_qp_1.pdf

how do you do question 32??

 

[Ayyan :D]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w02_qp_1.pdf

how do you do question 32??

B, i think.
As 72 is the normal pulse rate of humans.

 

[zackle09]

B, i think.
As 72 is the normal pulse rate of humans.

i thought that too but the answers A :/

 

[Ayyan :D]

i thought that too but the answers A :/

Oh. Maybe, the pulse should not exceed above 160 after exercise.
Normally the heart-beat after exercise is 160. But i thought it was B, because of the 72 thing.
But the 190 thing is a bit un-normal, the heart-beat should not go this high, for healthy people.
A, it is.

 

[zackle09]

Oh. Maybe, the pulse should not exceed above 160 after exercise.
Normally the heart-beat after exercise is 160. But i thought it was B, because of the 72 thing.
But the 190 thing is a bit un-normal, the heart-beat should not go this high, for healthy people.
A, it is.

ohh okay! thanks alot

 

[Ayyan :D]

ohh okay! thanks alot

No problem.

 

[ninesyllables]

http://papers.xtremepapers.com/CIE/...and AS Level/Biology (9700)/9700_w05_qp_1.pdf

How do you do question 30?

 

[6Astarstudent]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w05_qp_1.pdf

How do you do question 30?

firstly you immediately eliminate C and D because its "percentage saturation of haemoglobin in the blood leaving
an active muscle" which must have lower partial pressure of oxygen
now this is probably one of the more tricky questions, we know in an active muscle CO2 is produced.
the CO2 forms carbonic acid with water, and the carbonic acid further dissociates into hydrogen ions and hydrogencarbonate ions which lower the pH.
so it must be B, point on the ph 7.2 curve

this is outside of the syllabus but incase you're interested and does chemistry
you might wonder why the pH only dropped by 0.4, its because haemoglobins act as buffers to maintain the PH of the blood. it combines with H+ ions thus retains the pH.

 

[ninesyllables]

firstly you immediately eliminate C and D because its "percentage saturation of haemoglobin in the blood leaving
an active muscle" which must have lower partial pressure of oxygen
now this is probably one of the more tricky questions, we know in an active muscle CO2 is produced.
the CO2 forms carbonic acid with water, and the carbonic acid further dissociates into hydrogen ions and hydrogencarbonate ions which lower the pH.
so it must be B, point on the ph 7.2 curve

this is outside of the syllabus but incase you're interested and does chemistry
you might wonder why the pH only dropped by 0.4, its because haemoglobins act as buffers to maintain the PH of the blood. it combines with H+ ions thus retains the pH.

I see, thank you so much! You have helped me a lot :-D

 

[Apuurv A Mehra]

http://olevel.sourceforge.net/papers/9700/9700_s13_qp_12.pdf can somebody please help me with q14?

 

[sam1234]

http://olevel.sourceforge.net/papers/9700/9700_s13_qp_12.pdf can somebody please help me with q14?

Ans is C, cause only 9 bubbles can be produced, the mean number can't be in points? Imaging 9.2 bubbles that seems wrong, hence it's A, common sense, any idea about q19 same year and variant?

 

[perky1]

can anyone explain area of field of view ?? Q.3 M/J2010


http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_s10_qp_11.pdf

 

[6Astarstudent]

as it's a circle therefore the area is gonna be pi.r^2 so the radius is 55micrometer(found using eyepiece graticule) and they have already given you the value of pi i.e 3.14 so the area is found by multiplying 3.14*55*55=9498.5 and when written in standard form 9498.5 = 9.5*10^3

no answer is C
its 3.14*125*125=4.9*10^4
the radius is 50 small divisions and we know that 40 small divisions = 0.1mm or 100micrometers
each small division is therefore 100/40 = 2.5 micrometers
radius is thus 50x2.5= 125 micrometers

 

[Apuurv A Mehra]

no answer is C
its 3.14*125*125=4.9*10^4
the radius is 50 small divisions and we know that 40 small divisions = 0.1mm or 100micrometers
each small division is therefore 100/40 = 2.5 micrometers
radius is thus 50x2.5= 125 micrometers

shit sorry its jus slipped out my mind! :x

 

[panpan101]

Ans is C, cause only 9 bubbles can be produced, the mean number can't be in points? Imaging 9.2 bubbles that seems wrong, hence it's A, common sense, any idea about q19 same year and variant?

I think that the ans is A... cause if DNA replication stops, mitosis cannot occur any longer. Thus, the process of cell division will stop, but not immediately, because the telomeres are not completely replaced. So it eventually slows and stops until enough cells are produced.

If the telomeres are replaced, there will be DNA replication happening relentlessly. So the cell can keep on dividing.

Is the ans even A? lol

 

[sam1234]

I think that the ans is A... cause if DNA replication stops, mitosis cannot occur any longer. Thus, the process of cell division will stop, but not immediately, because the telomeres are not completely replaced. So it eventually slows and stops until enough cells are produced.

If the telomeres are replaced, there will be DNA replication happening relentlessly. So the cell can keep on dividing.

Is the ans even A? lol

Ans is A but your explanation doesn't seem to be right. Please explain more :/

 

[panpan101]

Basically, if interphase doesnt take place, mitosis will not happen.

With X,
Telomeres are replaced. So DNA replication will continue and mitosis will still continue

Without X,
Telomeres are still replaced... but NOT COMPLETELY. So once these telomeres gradually decrease in number, the process of cell division will eventually slow and stop. It does not stop immediately as there are still some telomeres but these telomeres are being used up every division. Once they are all used up, cell division stops.

 

[Trevor Jts]

Hi all How to do Nov 2008 Q8?

 

[Lujain M.]

The answer is C because basically sucrose is glucose + fructose. Fructose is an isomer of glucose so it has to be either C or D, C is the answer because it's alpha glucose as the OH group is belowCarbon . Hope it's clear.