AS Biology P1 MCQs Preparation Thread

[rockerkunal]

this is a crazy ass question, help me out please? (A) answwer is C

 

[Bluejeans#]

The two variable regions are the green and red parts. Read your textbook

oh okay thanks

 

[sweetjinnah]

this is a crazy ass question, help me out please? (A) answwer is C

this is answered in the previous page...

 

[SalmaXXXX]

w11qp13 question 33 pls help

In question 33, you don't really need to read all of the question since he told you at the end that the DNA is all now hybrid so one strand of DNA is N15 and one is N14. Remember that DNA is replicated by semiconservative replication. Imagine now that we have a bacteria with this hybrid DNA, when it starts to divide, her first daughter would get the N15 strand and would have the other strand made of nucleotides of N14 ( the medium it's grown in) her other daughter would get her mother's N14 strand and her other strand N14 from the nucloutides in her medium. Thus 50% of her daughters is hypride and the other 50 % is N14.

Look at the semi-conservative replication in this picture.

http://www.visionlearning.com/library/modules/mid187/Image/VLObject-5567-110727100736.jpg

 

[SalmaXXXX]

explain w11qp13 q 27

B is the correct answer, as Cells undergo mitotic division to repair the organism not the cell. If the Cell's DNA was mutated, making mitotis division would not repair the cell in any way

 

[Sara syed]

w10 qp13 pls explai q24 and 38

 

[fishcook]

http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_w12_qp_11.pdf
Q5 why is c wrong?

 

[HubbaBubba]

w10 qp13 pls explai q24 and 38

q24 - Each division on the SM has 40 EPG units. Since each SM division is 0.1mm, that means each 0.1mm has 40 EPG units. Therefore 1 EPG unit is = 0.0025 mm (2.5micrometers) 10/2.5 = 4 so the answer is B.

q38 - Somebody explained this a few pages earlier, just browse through, and you'll find it!

 

[SalmaXXXX]

nd ans mcq 1 of w o6 qp 1 plzzzzzzz

Okay, first of all you have to calculate how many graticule divisions does one stage macrometre occupies. It's 40 graticule divisions here. Then measure how many eye piece graticule units does one chloroplast occupies in the 2nd picture, that's 4 units. Now, you have to calculate how many stage macrometer divisions is the chloroplast.

1 S.M = 40 eye P.G
X SM = 4 eye p.G

x = 1 x 4 / 40 = 0.1 SM. The 1 SM = 0.1 mm. Thus the cloroplast = 0.1 x 0.1 = 0.01 mm. 0.01 mm x 1000 = 10 micrometer. Answer B

 

[sweetjinnah]

Okay, first of all you have to calculate how many graticule divisions does one stage macrometre occupies. It's 40 graticule divisions here. Then measure how many eye piece graticule units does one chloroplast occupies in the 2nd picture, that's 4 units. Now, you have to calculate how many stage macrometer divisions is the chloroplast.

1 S.M = 40 eye P.G
X SM = 4 eye p.G

x = 1 x 4 / 40 = 0.1 SM. The 1 SM = 0.1 mm. Thus the cloroplast = 0.1 x 0.1 = 0.01 mm. 0.01 mm x 1000 = 10 micrometer. Answer B

but how do v knw width is 4 units...

 

[SalmaXXXX]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w12_qp_11.pdf
Q5 why is c wrong?

C is wrong cause with this resolution you can't even see the membrane. It's not about the distance between two membranes. Your eyes won't be able to distinguish it from the medium around it. You need a resolution of more than 7nm to see the cell membrane

 

[SalmaXXXX]

but how do v knw width is 4 units...

From the figure you have, choose one of the chloroplasts present and see how many eye pieces graticule it occupies with your eyes.

 

[HubbaBubba]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w12_qp_11.pdf
Q5 why is c wrong?

q5 - C may seem slightly correct, but B seems even more correct. 220nm is 0.22micrometers so you won't be able to see anything that's 0.2 micrometers in width. You should take the one that is more true. Also if I recall, I don't recall being able to see two distinct membranes during practicals in light microscopes, so I guess you had to remember that?

 

[sweetjinnah]

From the figure you have, choose one of the chloroplasts present and see how many eye pieces graticule it occupies with your eyes.

owk i got it my mistake i was taking the whole cell...sorryyyyyyy to disturb u...

 

[Cesar_malik]

3

http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_w12_qp_11.pdf
Q5 why is c wrong?

300nm is larger then 600nm and since we half the wavlength to get the smallest difference which can be visable it is correct
B is correct ans (incorrect choice because 220 is smaller then .2 micros (200nm is .22 micrometer)
Just guessing iam not sure still
Anyone helping me with q7 paper 13 2011 oct novb

 

[HubbaBubba]

3
300nm is larger then 600nm and since we half the wavlength to get the smallest difference which can be visable it is correct
B is correct ans (incorrect choice because 220 is smaller then .2 micros (200nm is .22 micrometer)
Just guessing iam not sure still
Anyone helping me with q7 paper 13 2011 oct novb

Each division on the SM has 40 EPG units. Since each SM division is 0.1mm, that means each 0.1mm has 40 EPG units. Therefore 1 EPG unit is = 0.0025 mm (2.5micrometers)

Width begins at 61 units and ends at 70 units on EPG so width of the nucleus is 9 units. 9 * 2.5 = 22.5. The answer would be C

 

[Cesar_malik]

Each division on the SM has 40 EPG units. Since each SM division is 0.1mm, that means each 0.1mm has 40 EPG units. Therefore 1 EPG unit is = 0.0025 mm (2.5micrometers)

Width begins at 61 units and ends at 70 units on EPG so width of the nucleus is 9 units. 9 * 2.5 = 22.5. The answer would be C

He says the difference between two small divisons are .1 mm doest this make .1mm=80 divisons that us confusion
Thanks anyways

 

[HubbaBubba]

He says the difference between two small divisons are .1 mm doest this make .1mm=80 divisons that us confusion
Thanks anyways

Nope when they say each division, they mean each small division. Don't get confused with that! You could lose a lot of marks!

 

[SalmaXXXX]

The graph simply shows effect of increasing substrate concentration on the rate of reaction, non-competitive inhibitor doesn't let the rate of reaction reach the maximum limit, competitive inhibitor only initially decrease the rate of reaction, but the increase in substrate concentration diminish it's effect, so it will reach the maximum limit after time.

(Remember that there is no time here, I got confused by it in the beginning)

Okay so how will the graph look like if it was the amount of product formed and time? Does adding a small amount of non- competitive inhibitors stop the reaction so that the amount of product formed becomes constant (so no reaction is taking place) when the uninhibited reaction forms more product. In other words, does the non competitive inhibitor affects the amount of product formed or only the rate?

 

[Cesar_malik]

Nope when they say each division, they mean each small division. Don't get confused with that! You could lose a lot of marks!

Yea so each small divison has a large divison in the middle doesnt it ?
My method worked for other questsion like this but not for this