biology paper 1 doubts

[TCHS]

Is it just me or are the Oct/Nov past papers really more difficult than the May/June ones? :/

 

[Twinks05]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w11_qp_11.pdf

question number 24: Answer is C (0.07s) why?? I thought answer would be B

 

[Twinks05]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w11_qp_11.pdf

question number 24: Answer is C (0.07s) why?? I thought answer would be B

Also number 22, answer is A (amylose)..why??

Please and thank you!

 

[InnocentAngel]

I deduced after working the questions and from the cmbrdg bk that the sizes of the organelles are as such :Largest : Nucleus - chloroplst- GA- Nucleolus - mito - chloroplast grana -lysosome -ER - ribosome : Smallest. Is this order right ? Is chloroplst really bigger than mitochndria ? and is nucleolus larger than mitochondria or does it just stains more intensely ?

 

[ash369]

Also number 22, answer is A (amylose)..why??

Please and thank you!

I think that would be because amylase is an enzyme and enzymes are proteins by nature. The DNA maps out the basic protein formation and hence the answer is A. Hope I helped!

 

[externityxzx]

Salam alaykum,
Can someone please help with this question.
I don't get this.. ;(
Thank you in advance

1: atrioventricular valves close (semi-lunar valves are closed too)
2: semi-lunar valves open (atrioventricular valves are still closed)
3: semi-lunar valves close (atrioventricular valves are still closed)
4: atrioventricular valves open (semi-lunar valves are still closed)
so we calculate this by step 2 minus step 1 which is 0.03s
step 4 minus step 3 is 0.04s
together its 0.07sec

 

[Jevin Sanoo]

I deduced after working the questions and from the cmbrdg bk that the sizes of the organelles are as such :Largest : Nucleus - chloroplst- GA- Nucleolus - mito - chloroplast grana -lysosome -ER - ribosome : Smallest. Is this order right ? Is chloroplst really bigger than mitochndria ? and is nucleolus larger than mitochondria or does it just stains more intensely ?

Mitochondria is larger than nucleolus. Check the May/June 2008 p1 number 1.

 

[externityxzx]

Why is the answer A ?? Where is the leaf turgid ? in diagrm1 or 2 ??View attachment 18189

The leaf is more turgid in diagram 2 as the water potential is less negative in solution Y

 

[railey]

1: atrioventricular valves close (semi-lunar valves are closed too)
2: semi-lunar valves open (atrioventricular valves are still closed)
3: semi-lunar valves close (atrioventricular valves are still closed)
4: atrioventricular valves open (semi-lunar valves are still closed)
so we calculate this by step 2 minus step 1 which is 0.03s
step 4 minus step 3 is 0.04s
together its 0.07sec

Jazakallah. Thank You very very much!

 

[InnocentAngel]

The leaf is more turgid in diagram 2 as the water potential is less negative in solution Y

Lol i ddmt realise it was turgid in 2 , i thought tht the more bent it is , the more it contains water . Okay thanks

 

[Kumkum]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w11_qp_12.pdf
Please help me with question number 29..and what is meant by "more negative and less negative"?

 

[Irfan1995]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w11_qp_12.pdf
Please help me with question number 29..and what is meant by "more negative and less negative"?

More negative = less water potential = more dissolved solutes
Less negative = more water potential = less dissolved solutes (purer water)

I've fully explained this in one of my earlier posts yesterday, check somewhere around page 2 or 3.

 

[Kumkum]

More negative = less water potential = more dissolved solutes
Less negative = more water potential = less dissolved solutes (purer water)

I've fully explained this in one of my earlier posts yesterday, check somewhere around page 2 or 3.

ok thank you but what is the answer?

 

[InnocentAngel]

Mitochondria is larger than nucleolus. Check the May/June 2008 p1 number 1.

so its : Nucleus - chloroplst- GA-mito- Nucleolus - chloroplast grana -lysosome -ER - ribosome -centriole : Smallest But nucleolus stains more easily on the microscpe than mito koz its compact with all the nucleic acid .
Any other changes anyone?

 

[Irfan1995]

ok thank you but what is the answer?

Sucrose is actively transported to the phloem (B) from the leaves (mesophyll cells/A)
Sucrose is unloaded (taken in) near the roots (C and D).
So sucrose is most concentrated in the phloem near the leaves (B).
Higher concentration = more negative water potential.
So the answer is B.

 

[Kumkum]

Sucrose is actively transported to the phloem (B) from the leaves (mesophyll cells/A)
Sucrose is unloaded (taken in) near the roots (C and D).
So sucrose is most concentrated in the phloem near the leaves (B).
Higher concentration = more negative water potential.
So the answer is B.

oh ok...thank you!

 

[externityxzx]

7 What is the theoretical number of chemically different dipeptides that may be assembled from 12
different types of amino acids?
A 24 B 72 C 144 D 400
This is what i did 2 x 12 x 3=72 but the answer is C.... can anyone please explain this to me?

 

[Ashiq Sookarry]

i think d is the answer coz in the root higher pressure for water to move up to xylem.

 

[Irfan1995]

so its : Nucleus - chloroplst- GA-mito- Nucleolus - chloroplast grana -lysosome -ER - ribosome -centriole : Smallest But nucleolus stains more easily on the microscpe than mito koz its compact with all the nucleic acid .
Any other changes anyone?

Ribosome = 20 nm in prokaryotes and 22 nm in eukaryotes
Centrioles: length = 700 nm, diameter = 250 nm

EDIT: Also, the thickness of a cell membrane is 7 nm, which makes it the thinnest organelle.

 

[Irfan1995]

7 What is the theoretical number of chemically different dipeptides that may be assembled from 12
different types of amino acids?
A 24 B 72 C 144 D 400
This is what i did 2 x 12 x 3=72 but the answer is C.... can anyone please explain this to me?

Dipeptide = 2 amino acids
You have 12 possibilities for the first amino acid
You also have 12 possibilities for the second amino acid
So you have a total of 12 x 12 = 144 possibilities for the dipeptide.