A level Biology: Post your doubts here!

[Thought blocker]

How were the exams ?

 

[♣♠ Magnanimous ♣♠]

How were the exams ?

you know about mine

 

[Thought blocker]

lol

 

[Asad rehman]

how were yours thought blocker?

 

[Thought blocker]

how were yours thought blocker?

I raped Physics and Math, but Chemistry, English and Computing raped me.
Gonna repeat my Exams. *Sigh*

 

[♣♠ Magnanimous ♣♠]

I raped Physics and Math, but Chemistry, English and Computing raped me.
Gonna repeat my Exams. *Sigh*

raped hahahahaha

 

[Thought blocker]

raped hahahahaha

 

[♣♠ Magnanimous ♣♠]

 

[ShreeyaBeatz]

hey guys i have bio exam in O/n
so can someone explain the follwing questions?
9700/01/m/j/05 questions- 14,11,5
9700/01/o/n/04 questions- 27,,30,39,20,13 and 5
Help would be really appreciated

 

[AnujaK]

Heeyy everyone! I've started a site that'll give you SOLVED past papers! Really helpful! Do check it out Also has some worksheets and revision notes!
https://sites.google.com/site/fromatoscom/

 

[Uttam Shrestha]

can someone please tell me about the free pdf link of Biological Science by Scoop. I need the books for reference as I heard that the book is the best book available. Please give me the link from which I can download it.

 

[ZaqZainab]

I raped Physics and Math, but Chemistry, English and Computing raped me.
Gonna repeat my Exams. *Sigh*

you said mechanics didnt go well it is a part of maths

 

[shahroxe]

i got an A in AS.... break down was A A B
im scared abt paper 4... if i get around a 75 in p4 and a 24 in p5 will i be able to maintain that grade????

 

[Thought blocker]

you said mechanics didnt go well it is a part of maths

Have a hope of grade B, as my P1 was good.

 

[♣♠ Magnanimous ♣♠]

you said mechanics didnt go well it is a part of maths

Have a hope of grade B, as my P1 was good.

 

[♣♠ Magnanimous ♣♠]

can someone please tell me about the free pdf link of Biological Science by Scoop. I need the books for reference as I heard that the book is the best book available. Please give me the link from which I can download it.

Can you elaborate your thing as I am not getting a clear idea of wat you talking about.

 

[ALFRED DEI AMOEH]

hey guys i have bio exam in O/n
so can someone explain the follwing questions?
9700/01/m/j/05 questions- 14,11,5
9700/01/o/n/04 questions- 27,,30,39,20,13 and 5
Help would be really appreciated

9700/01/m/j/05 questions- 14,11,5

Question 14

Options C and D are both incorrect. At R, the enzyme is working at the optimum, so its structure would not be starting to break and at
S, the enzyme, not the substrate would be completely denatured. Option B is wrong because kinetic energy increases as temperature increases and therefore at point Q on the graph, kinetic energy was not at its highest. This leaves only choice A as the correct answer .


Question 5

Choice C is the correct answer because the mitochondria were kept in a 0.25 mol dm–3 sucrose solution in
order to maintain the organelles osmotic integrity. The respiratory substrate used by mitochondria is
glucose, not sucrose.

Question 11

Options A and B are incorrect because from the the given graph, the increasing symmetry started decreasing only after pH 4 and not pH 2. Option C is wrong because primary structure cannot be destroyed by a change in pH or any other conditions ( change in temperature ). Choice D is correct because at pH 10, the secondary structure is distorted.



9700/01/o/n/04 questions- 27,,30,39,20,13 and 5

Question 5

In finding the magnification of the diagram , you use the formula : Image Size
Actual Size.
From the diagram, the image size is given as 150mm and the question gives the actual size to be 7.5mm. So you plug in the values into the formula and you get your answer : X 20 ( Option C )

Question 20

The correct answer is D because the daughter cell - cell 2- has half the number of chromosomes of the parent -cell 1- i.e 46 chromosomes. Every chromosome consists of two chromatids and every chromatid consists of one DNA molecule. Hence, cell 1 having 46 chromosomes end up having 92 ( 46 X 2) DNA molecules and cell 2 end up getting 46 DNA molecules ( 23 X 2). Also the DNA has already replicated before a cell reaches prophase.

Question 27

Option B and D are wrong because the red blood cell has no nucleus and so it can neither synthesise proteins nor divide. Choice C is also wrong because it is only the White Blood Cells that undergo phagocytosis ( phagocyte) . Choice A is the only correct remaining answer.

Question 30


Choice A is correct because the apoplast acts as all the non-living water-conducting parts of a plant .The direct effect of the fungal growth would be blockage of the xylem vessels, which are part of the apoplast.


Question 39

Choice D is wrong because the present of nitrates in the soil doesn't decrease the number of denitrifying bacteria. Choice C is wrong as well because although the availability of nitrate through diverse means adds energy to the ecosystem , it is not the reason for the increase in the crop production. Also, Choice B is wrong because nitrogen fixation is carried out by nitrifying bacteria so as to make available nitrates for the plant hence, if nitrates is made available via the application of the fertilizer, there is no need for the fixation of more nitrogen by leguminous plant . Choice A is the only correct answer because , green plant use the the nitrate to carry out the protein synthesis.



I hope the explanations given above shall be well understood . Unfortunately, I couldn't really understand how they came by the answer to question 13.

 

[ShreeyaBeatz]

9700/01/m/j/05 questions- 14,11,5

Question 14

Options C and D are both incorrect. At R, the enzyme is working at the optimum, so its structure would not be starting to break and at
S, the enzyme, not the substrate would be completely denatured. Option B is wrong because kinetic energy increases as temperature increases and therefore at point Q on the graph, kinetic energy was not at its highest. This leaves only choice A as the correct answer .


Question 5

Choice C is the correct answer because the mitochondria were kept in a 0.25 mol dm–3 sucrose solution in
order to maintain the organelles osmotic integrity. The respiratory substrate used by mitochondria is
glucose, not sucrose.

Question 11

Options A and B are incorrect because from the the given graph, the increasing symmetry started decreasing only after pH 4 and not pH 2. Option C is wrong because primary structure cannot be destroyed by a change in pH or any other conditions ( change in temperature ). Choice D is correct because at pH 10, the secondary structure is distorted.



9700/01/o/n/04 questions- 27,,30,39,20,13 and 5

Question 5

In finding the magnification of the diagram , you use the formula : Image Size
Actual Size.
From the diagram, the image size is given as 150mm and the question gives the actual size to be 7.5mm. So you plug in the values into the formula and you get your answer : X 20 ( Option C )

Question 20

The correct answer is D because the daughter cell - cell 2- has half the number of chromosomes of the parent -cell 1- i.e 46 chromosomes. Every chromosome consists of two chromatids and every chromatid consists of one DNA molecule. Hence, cell 1 having 46 chromosomes end up having 92 ( 46 X 2) DNA molecules and cell 2 end up getting 46 DNA molecules ( 23 X 2). Also the DNA has already replicated before a cell reaches prophase.

Question 27

Option B and D are wrong because the red blood cell has no nucleus and so it can neither synthesise proteins nor divide. Choice C is also wrong because it is only the White Blood Cells that undergo phagocytosis ( phagocyte) . Choice A is the only correct remaining answer.

Question 30


Choice A is correct because the apoplast acts as all the non-living water-conducting parts of a plant .The direct effect of the fungal growth would be blockage of the xylem vessels, which are part of the apoplast.


Question 39

Choice D is wrong because the present of nitrates in the soil doesn't decrease the number of denitrifying bacteria. Choice C is wrong as well because although the availability of nitrate through diverse means adds energy to the ecosystem , it is not the reason for the increase in the crop production. Also, Choice B is wrong because nitrogen fixation is carried out by nitrifying bacteria so as to make available nitrates for the plant hence, if nitrates is made available via the application of the fertilizer, there is no need for the fixation of more nitrogen by leguminous plant . Choice A is the only correct answer because , green plant use the the nitrate to carry out the protein synthesis.



I hope the explanations given above shall be well understood . Unfortunately, I couldn't really understand how they came by the answer to question 13.

Thanks for the help! Highly appreciated this

 

[Starlight97]

is it better to make biology notes or we should prefer books more

 

[ZaqZainab]

is it better to make biology notes or we should prefer books more

why not do both but take notes with understanding. I made notes which i hardly used but i used the book to make notes made a better understanding