AS Biology P1 MCQs Preparation Thread

[confused123]

what is the effect of the enzyme DNA ligase?
synthesis of human insulin by genetically manipulated bacteria involves the use of the enzyme reverse transcriptase.
are these two mcq's questions in as level syllabus?

 

[confused123]

What's 'Aortic Stenosis'?

 

[geek101]

what is the effect of the enzyme DNA ligase?
synthesis of human insulin by genetically manipulated bacteria involves the use of the enzyme reverse transcriptase.
are these two mcq's questions in as level syllabus?

yep they are!

 

[confused123]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s05_qp_1.pdf
8, 18, 35 ( why not odr options..?) , 37, 38 why not B?

 

[confused123]

yep they are!

Ohh! Then can u please answer the questions.

 

[geek101]

Ohh! Then can u please answer the questions.

june 03 Q20:
It says: RNA...is used to make DNA coding for human insulin. Which enzyme is used to make the DNA?
the answer is C, reverse transcriptase

nov 03 Q22
It says which enzymes rejoins sections of DNA in genetic engineering? The answer is A DNA ligase...

hope this helps, just keep in mind the definitions are in the questions.

 

[zainabk]

u said it is also a hereditary disease which suggest that you might have thought Hiv aids or any other disease to be hereditary from the given options. if that is so then you are wrong. no other disease has a hereditary link.

sickle cell anaemia is a hereditary disease and can pass from parent to child. but these sort of errors are very rare when genetic material passes from parent to child. this will be second least likely after malaria.

Yes I know that only sickle cell is hereditary I get the question now.Thanks for the help

 

[egy]

what is the effect of the enzyme DNA ligase?
synthesis of human insulin by genetically manipulated bacteria involves the use of the enzyme reverse transcriptase.
are these two mcq's questions in as level syllabus?

DNA ligase is an enzyme which links okazaki fragments formed during DNA replication ((incontinous replication ))

and yes itis in AS level

 

[i love my country]

guys i have little problem in understanding this questions 20 and 21 in may\june 2008 and i wish the best for you all in the remaining exams...

 

[Peter Check]

Does meiosis help in genetic variation?? If not, what does??

 

[shan5674]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s06_qp_1.pdf

Why is 23 and 24 - B? :S

 

[KurayamiKimmi]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s03_qp_1.pdf
can any1 pls explain question no 30 ^_^

 

[KurayamiKimmi]

Does meiosis help in genetic variation?? If not, what does??

yes meiosis results in genetic variation-because you inherit one from the mother and the other from the father.
oh and also because of the crossing over of non-sister chromatids in meiosis

 

[KurayamiKimmi]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s06_qp_1.pdf

Why is 23 and 24 - B? :S

for 23-
There are 6000 nucleotides on a double stranded DNA -only one strand is transcripted by mRNA so we have 3000 nucleotides
each nucleotide has one nitrogenous base -Adenine/Cytosine/Guanine/Thymine
an amino acid is coded for by three N bases -so using ratio method
No of amino acids: Nucleotides
1: 3
x :3000
dividing 3000 by 3 gives us 1000

 

[KurayamiKimmi]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s06_qp_1.pdf

Why is 23 and 24 - B? :S

for q no 24
it says 20% are cytosine
each cytosine base pairs with a guanine base so that means there are 0 % guanine bases too . this gives us 40% of the bases (C+G[20+20]) 100%-40% =60%
60% are thymine and adenine since one thymine pairs with one adenine the 60% is equally divided between A and T so u have 30% bases that are thymine -in RNA uracil replaces thymine so that means uracil will also be 30%

 

[JulyMei]

Can anyone explain this graph? I don't really get it.. Thanks in advance.

 

[KurayamiKimmi]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s03_qp_1.pdf
can any1 pls explain question no 30 ^_^
http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s04_qp_1.pdf
can anyone explain qno 23 too please =/

 

[KurayamiKimmi]

DNA ligase is an enzyme which links okazaki fragments formed during DNA replication ((incontinous replication ))

and yes itis in AS level

okazaki fragments?? i kinda understand what ur getting at but could u explain this term?

 

[hmlahori]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w03_qp_1.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w03_er.pdf
Q 28, 32 & 35 Can anyone explain their answers?

 

[rogue94]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s03_qp_1.pdf
can any1 pls explain question no 30 ^_^
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s04_qp_1.pdf
can anyone explain qno 23 too please =/

For question no. 30 its option D because aerobic respiration requires both glucose and oxygen, both of which are brought to the muscles via the blood, so an increase in volume of blood flow would mean that more glucose and oxygen are provided to muscles and more waste products are carried away. The rest of the options are only related to oxygen supply to muscles.
For question no. 23 simply replace all the T's in the code, with U's giving the correct option, B. First you have to find the complementary mRNA codes, then find the tRNA codes complementary to the mRNA codes that you just found, leading you back to the original (DNA) code given in the question, with only the T's replaced by the U's since its RNA (tRNA) and not DNA. If they had given you tRNA anti-codons and you had find the DNA codes, then you would have replaced all the U's in the anti-codons with T's to find the answer.