AS Biology P1 MCQs Preparation Thread

[Trevor Jts]

Thank you very much! If possible, could you pls help me another onE?
Nov 2007 Q19
Shouldn't statement 4 chromosomes uncoil be in the first order?

 

[6Astarstudent]

Thank you very much! If possible, could you pls help me another onE?
Nov 2007 Q19
Shouldn't statement 4 chromosomes uncoil be in the first order?

no, at prophase the chromosomes coil up
and at the end of telophase they uncoil to get ready to be replicated via semi conservative replication in interphase (which is not part of mitotic cycle)

 

[Trevor Jts]

no, at prophase the chromosomes coil up
and at the end of telophase they uncoil to get ready to be replicated via semi conservative replication in interphase (which is not part of mitotic cycle)

Got it! THANKS!

 

[Trevor Jts]

Hello, anyone could explain Q21 in Nov 2006 for me?

 

[Trevor Jts]

Hello, anyone could explain Q21 in Nov 2006 for me?

 

[6Astarstudent]

Hello, anyone could explain Q21 in Nov 2006 for me?

DNA is semi conservative replication, DNA has 2 strands
at the start it is all made of 15N. so 15N - 15N DNA
it grows replicate under 14N
so all 15N will pair with a 14N so 15N-14N DNA with a overall weight of 14.5, this is lighter so this is at Y after centrifuge.

and for next generation still growning under 14N
half of the original strands are now 14N, and half are 15N
so 14N combines with 14N forming 14N-14N, and 15N combines with 14N forming 15N-14N. so 50% at X which is lightest 14N-14N strand, and 50% at Y which is 14N-15N

 

[Trevor Jts]

Thank you very much for the 3rd time!

 

[Wasim Mohammed]

How was the AS level biology exam paper 11 and 12 ?

 

[Trevor Jts]

Hey anyone can help?
June 2004 q33

 

[Rosy S]

I have it tomorrow... why ask now?

How was the AS level biology exam paper 11 and 12 ?

 

[zackle09]

http://papers.xtremepapers.com/CIE/...and AS Level/Biology (9700)/9700_s07_qp_1.pdf
can someone pls tell me how question 1 is B? im confused :/

 

[enchanted era]

Hey anyone can help?
June 2004 q33

Here is a table that you might find helpful. better memorize it because i m pretty sure questions from this table comes every year.
Ps- easy way to memorize about alveoli is to keep in mind that the function of alveoli is only exchange of gases. so the rest of the materials are not needed here.

 

[enchanted era]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s07_qp_1.pdf
can someone pls tell me how question 1 is B? im confused :/

convert all the units into metre (reduces confusion)
so, 750nm= 7.5x10-7
and 15um= 1.5x10-5
then just divide them 1.5x10-5 / 7.5x10-7 = 20

 

[zackle09]

convert all the units into metre (reduces confusion)
so, 750nm= 7.5x10-7
and 15um= 1.5x10-5
then just divide them 1.5x10-5 / 7.5x10-7 = 20

ohh lol that was easy..thanks so much!

 

[Jinosupreme]

A graft of tissue, such as skin, from a different person is usually rejected by the body.
Which statement about graft rejection is correct?
A The graft is rejected by B-lymphocytes because they make and release antibodies which react with the surface antigens on the graft cells.
B The graft is rejected by B-lymphocytes because T-lymphocytes are not stimulated to produce antibodies.
C The graft is rejected by T-lymphocytes because the graft tissue causes T-lymphocytes to release antibodies.
D The graft is rejected by T-lymphocytes because they circulate in the blood and can gather at the graft site.

Answer is D why?

 

[enchanted era]

no problem

ohh lol that was easy..thanks so much!

 

[enchanted era]

A graft of tissue, such as skin, from a different person is usually rejected by the body.
Which statement about graft rejection is correct?
A The graft is rejected by B-lymphocytes because they make and release antibodies which react with the surface antigens on the graft cells.
B The graft is rejected by B-lymphocytes because T-lymphocytes are not stimulated to produce antibodies.
C The graft is rejected by T-lymphocytes because the graft tissue causes T-lymphocytes to release antibodies.
D The graft is rejected by T-lymphocytes because they circulate in the blood and can gather at the graft site.

Answer is D why?

its a fact, memorize it elaborating and finding logical explanations will lead to something beyond our level i guess . the fact is t-lymphocytes are responsible of dealing with graft tissues may be because they got the killer cells and b-lymphocytes releases antibodies which got no complementary binding sites to the antigens of graft cells :/

 

[Rosy S]

convert all the units into metre (reduces confusion)
so, 750nm= 7.5x10-7
and 15um= 1.5x10-5
then just divide them 1.5x10-5 / 7.5x10-7 = 20

Here is a table that you might find helpful. better memorize it because i m pretty sure questions from this table comes every year.
Ps- easy way to memorize about alveoli is to keep in mind that the function of alveoli is only exchange of gases. so the rest of the materials are not needed here.

That Table was really helpful do you have such kind of other useful information??

 

[perky1]

http://olevel.sourceforge.net/papers/9700/9700_s13_qp_11.pdf
q.22

 

[enchanted era]

That Table was really helpful do you have such kind of other useful information??

you are welcome . umm depends on what your doubts are