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biology paper 1 doubts

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Post any doubts you have in paper 1 for bio...
Let's help each other out on this! :)
Good luck(y)
 
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Paper 1 (MULTIPLE-GUESS) Hardest Paper in AS level i would say...
how do you revise?
 
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by solving all the pastpaper questions till you're perfect at them.
What are you finding hard in paper 1?
I would say mostly with figuring out which option is the corect one, cause in most of the questions each and every option is right, u just have find which one is the answer to the question.
 
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The correct answer is B, but I don't get why !
I chose A when I solved it as I thought that the high temperature of volcano would kill the bacteria.
 
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1) Volcanic eruptions don't necessarily have to kill bacteria, as they can sometimes have enzymes which are suited to high temperatures (especially archea)
2) Volcanic activity enriches soil, so it would be full of nitrifying bacteria
3) Obviously, volcanic eruptions would kill all animals and plants

The only option that matches all three would be B.

Even if you didn't know that lava enriches the soil, you must know that all other forms of life must die, and the only option with "decrease" with animals and plants would be B.
 
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View attachment 17946
The correct answer is B, but I don't get why !
I chose A when I solved it as I thought that the high temperature of volcano would kill the bacteria.

Since the atmosphere contains great amounts of dust as stated in the question, perhaps it will be harder for producers to obtain CO2? Therefore photosynthesis would be affected & as a result some plants may die, therefore creating a decrease in amount of PRODUCERS. Now, since Primary consumers feed on producers, their number will also decrease (as less food ie plants available). Secondary consumers feed on primary consumers & since the Primary consumers have decreased, Secondary will also decrease. Thus, answer is B. Didn't even have to consider the nitrifying bacteria :p

Hope my thought process was correct :/
 
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Paper 1 (MULTIPLE-GUESS) Hardest Paper in AS level i would say...
how do you revise?

I second xtremeforums! I was pretty bad at Paper 1 too but ever since I revised everything thoroughly & THEN attempted the past papers (with a better understanding of the topics), I moved from grade E to an A. InshA'Allah our papers will be great!
 
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Since the atmosphere contains great amounts of dust as stated in the question, perhaps it will be harder for producers to obtain CO2? Therefore photosynthesis would be affected & as a result some plants may die, therefore creating a decrease in amount of PRODUCERS. Now, since Primary consumers feed on producers, their number will also decrease (as less food ie plants available). Secondary consumers feed on primary consumers & since the Primary consumers have decreased, Secondary will also decrease. Thus, answer is B. Didn't even have to consider the nitrifying bacteria :p

Hope my thought process was correct :/

1) Volcanic eruptions don't necessarily have to kill bacteria, as they can sometimes have enzymes which are suited to high temperatures (especially archea)
2) Volcanic activity enriches soil, so it would be full of nitrifying bacteria
3) Obviously, volcanic eruptions would kill all animals and plants

The only option that matches all three would be B.

Even if you didn't know that lava enriches the soil, you must know that all other forms of life must die, and the only option with "decrease" with animals and plants would be B.

Thank you guys, I totally get it now!
 
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should I revise the whole syllabus again?
and should I solve the pastpapers twice? :confused:
 
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should I revise the whole syllabus again?
and should I solve the pastpapers twice? :confused:
If you feel that your concepts aren't clear enough, revise the syllabus. Use some notes to revise, that would be quicker than revising from the book. If you are going to revise, then plan a crash course studying schedule so you finish it in 2 days! Dont waste more than 2 days on it...
Then practice pastpapers. Not necessary to do them twice. Mark the questions you get wrong and revise them before the exam. Try to do as many years as possible. The more you practice the better ud get at them.
 
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If you feel that your concepts aren't clear enough, revise the syllabus. Use some notes to revise, that would be quicker than revising from the book. If you are going to revise, then plan a crash course studying schedule so you finish it in 2 days! Dont waste more than 2 days on it...
Then practice pastpapers. Not necessary to do them twice. Mark the questions you get wrong and revise them before the exam. Try to do as many years as possible. The more you practice the better ud get at them.
thank you very much :)
 
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so guys, what do you think the grade threshold for an A in AS would be?
 
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How could it be D? If water moves in the potato cylinder, then the solution would be more concentrated (same amount of solute, but with a reduced volume, and since concentration is inversely proportional to volume, concentration increases). If the solution is more concentrated, it would have a more negative water potential.

Hope that helps.
 
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How could it be D? If water moves in the potato cylinder, then the solution would be more concentrated (same amount of solute, but with a reduced volume, and since concentration is inversely proportional to volume, concentration increases). If the solution is more concentrated, it would have a more negative water potential.

Hope that helps.
Thanks alot for the help! but,
The water moves in... same solute, and now MORE water... that would reduce the water potential (less negative)?
 
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More water for the potato cylinder, but less water remaining in solution.
It's just like a sponge absorbing water. The sponge holds more water, but the quantity of water in the surroundings is reduced.
Makes sense?
 
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More water for the potato cylinder, but less water remaining in solution.
It's just like a sponge absorbing water. The sponge holds more water, but the quantity of water in the surroundings is reduced.
Makes sense?
OH ok thank you soo much! I thought it said the water potential of the CELLS will become less negative...
 
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