AS Biology P1 MCQs Preparation Thread

[Cesar_malik]

http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_w12_qp_13.pdf thats the correct link..

Thank you at last...pheww
Ok remmb the large hollow balls like are alwyas xylem the smaller one are phloem
Look at a diagram of vascular bundle in a book or google it
And in vascular bundle in leaf there is cabium between phloem and xylem with xylem in the inner side while phloem in the outsode
In stem its xylem star middle with pholem outsode and in leaf when theres a hump like in longitudnal i thhink
Towards the bigger hump is phloem and on the down side is xylem still someone check what i wrote
Iam not good at helping other and i dont hav any book right now so its more like 50 50 probability that iam right

 

[kingos3111]

there was a question active transport is it and active transport and diffusion is that correct i wrote answer A is it correct

 

[zackle09]

http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_w11_qp_11.pdf can someone please explain question 24 to me!!

 

[Cesar_malik]

http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_w11_qp_11.pdf can someone please explain question 24 to me!!

Ok so if u look carefully he is asking about time taken the valves are closed ok so at first when semi lunar valves are open the atro ventricular valves should be closed use that time and then use the time ventricular vves are open and semj lunar closed since hes asking about both are open are close substract the time u calculated fro total time of heart beat that would be I guess 0.7 soe suppose .2 for semilunar open .1 for semi lunar closed so .3 substract .7 from .3 u will get the time diy iam just explaining as this is a cellphone so difficult to understand the quest

 

[zackle09]

Ok so if u look carefully he is asking about time taken the valves are closed ok so at first when semi lunar valves are open the atro ventricular valves should be closed use that time and then use the time ventricular vves are open and semj lunar closed since hes asking about both are open are close substract the time u calculated fro total time of heart beat that would be I guess 0.7 soe suppose .2 for semilunar open .1 for semi lunar closed so .3 substract .7 from .3 u will get the time diy iam just explaining as this is a cellphone so difficult to understand the quest

ohhh no problem i understood it now... Thanks so much

 

[Lujain M.]

Can someone help me with q22 nov 10 v1?

 

[Jinosupreme]

The following events occur during transcription.
1 Bonds break between complementary bases.
2 Bonds form between complementary bases.
3 Sugar-phosphate bonds form.
4 Free nucleotides pair with complementary nucleotides.
Before the mRNA leaves the nucleus, which events will have occurred twice?
A 1 and 2 only
B 1, 3 and 4 only
C 2, 3 and 4 only
D 1, 2, 3 and 4

Anyone help?
Answer is A

 

[Cesar_malik]

The following events occur during transcription.
1 Bonds break between complementary bases.
2 Bonds form between complementary bases.
3 Sugar-phosphate bonds form.
4 Free nucleotides pair with complementary nucleotides.
Before the mRNA leaves the nucleus, which events will have occurred twice?
A 1 and 2 only
B 1, 3 and 4 only
C 2, 3 and 4 only
D 1, 2, 3 and 4

Anyone help?
Answer is A

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

 

[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?