A level Biology: Post your doubts here!

[Abdul Hanan]

Ok thanks! but the nitrosomonas and nitrobacter are in correct place right?

NH4+ ---(nitrosomonas)---> NO2- ------(nitrobacter)-----> NO3-
YES they are on the correct spot.

 

[Abdul Hanan]

Can anyone tell me stuff which is to learn and we may have not learned yet like any enzyme names? I know bacteria names in nitrogen cycle...
apart from that any names to learn?

 

[princess Anu]

somebody help with nov 14 /23 Q2 C
MS mentions reference to sizes of individuals.. can somebody explain what reference needs to be made?

 

[ParulS]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w09_qp_51.pdf
Can some one please do 2) c) ii)

 

[Abdul Hanan]

somebody help with nov 14 /23 Q2 C
MS mentions reference to sizes of individuals.. can somebody explain what reference needs to be made?

There is a loss of energy at each trophic level by respiration/egestion/excretion so less energy available to Herons. Heron is largest in size in the food chain and require large amount of energy to fulfill its requirements so less of them exist as overall less energy available.

 

[Awesome12]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w09_qp_51.pdf
Can some one please do 2) c) ii)

The mean increase in the control culture is 6.18.

The initial no. of cells present is given = 3000 = 3.0 (as plotted in the table)

Using the given formula:

(6.18-3.0 / 3.0) * 100

 

[ParulS]

The mean increase in the control culture is 6.18.

The initial no. of cells present is given = 3000 = 3.0 (as plotted in the table)

Using the given formula:

(6.18-3.0 / 3.0) * 100

Thanks

 

[Studydayandnight]

Hey! Guys could you please help me out here? My final AS bio paper 2 is tomorrow! Pray that it goes well!

Anyway, so in this question, for K, the left ventricle is relaxing and so is the left atria, and the av valve is open and the aortic valve is closed, so the conditions are same as in the H stage, so why is the left atria relaxing in K? Shouldn't it contract?

Is there a mistake in the mark scheme?

 

[nehaoscar]

Hey! Guys could you please help me out here? My final AS bio paper 2 is tomorrow! Pray that it goes well!

Anyway, so in this question, for K, the left ventricle is relaxing and so is the left atria, and the av valve is open and the aortic valve is closed, so the conditions are same as in the H stage, so why is the left atria relaxing in K? Shouldn't it contract?

Is there a mistake in the mark scheme?

The atria is filling with blood, but it isn't itself contracting in K
when it contracts blood flows from atria to ventricles
In this case the atria are filling up

 

[MYLORD]

what is the proper definition of heterotrophs ? (2 Marks)

 

[Farheen1201]

he

what is the proper definition of heterotrophs ? (2 Marks)

heterotrophs are organisms that feed on other organisms to obtain the organic compounds.

 

[Farheen1201]

Assalamu alaikum and good luck to all of you for the paper. Mine's today

 

[darks]

Fill in the blanks :
1. habitat
2. community
3. consumers
4. niche
5. ecosystem
am i right?

 

[darks]

we can't discuss the paper today its part of the rules of XPC btw 2 is organisms

a group of different organisms is community? btw its ok if i got this one wrong i thought i was going to get all 5 wrong.... i'm just too poor in these type of questions.

 

[Mahmood Magdy]

Fill in the blanks :
1. habitat
2. community
3. consumers
4. niche
5. ecosystem
am i right?

2 Is a population
3 is producers
Check the definitions in the syllabus. I got all correct except 3.

 

[nehaoscar]

We can discuss the paper this time tomorrow (i.e 24 hours)

 

[Studydayandnight]

Omg, I know we can't discuss the answers. But how did you guys find it?

I think mine could have been better, I made the stupidest mistakes, striking out the correct answer and then writing the wrong one! That cost me like three marks :'(

 

[Sadi66]

without disclosing the contents, how was the paper:

 

[Mahmood Magdy]

It was a good paper, but not up to the point. You see some questions were really tricky but some were just normal. What about you guys ?

 

[Jeezan]

It was a good paper, but not up to the point. You see some questions were really tricky but some were just normal. What about you guys ?

I agree with you
it was almost an average paper