A level Biology: Post your doubts here!

[ashcull14]

the lug worm lives in a burrow in the sand just above low water mark.it has haemoglobin in its blood. at low tide it retreats to its burrow and shuts itself.....it is cut off from external sources of oxygen until the sea water returns....what dissociation curve for haemoglobin????
closer to % saturation axis or closer to partial pressure of o2 axis??

 

[Studydayandnight]

wht paper is this?

Here's the link!

http://www.mrsmbpj.com/IGCSE/pdf/9700_w12_qp_11.pdf

 

[Amandaissocoollike]

How do we solve this? PLEASE HELP ASAP!

Correct answer is A.

Simply subtract the energy lost at each trophic level, so: 23000-8000=15000. Then, 15000-10500=4500 and so on. The final answer you get for the third trophic level, you divide it by 23,000 (the original amount of energy) and multiply by 100 to get the answer, which is 1.3%.

 

[Lola_sweet]

Here's the link!

http://www.mrsmbpj.com/IGCSE/pdf/9700_w12_qp_11.pdf

i really ve no idea on hw to solve this

 

[nehaoscar]

hes talking about ONLY mitosis...if u remember cancer is a result of uncontrolled mitosis ONLY
well its confusing but a combination of 2 nd 3 are more likely bcz the chances of bacterial transmission increases with greater no of people nd lack of washing facilities whereas for the 1st one ...bact transmission can be prevented widout refregeration like proper packing so and so.....

But then B-lymph and root hair... what other than mitosis occurs?

 

[Studydayandnight]

How do we solve these annoying eco system calculation questions? -_____-

 

[nehaoscar]

doesnt co2 have higher affinity to o2?
but then its b??? how? :/

 

[Studydayandnight]

Does anyone out there know how to solve this? :'(

Correct answer is A.

 

[hizirofaki]

plz help https://www.xtremepapers.com/community/attachments/11160221_10204517600243144_750592502_n-jpg.53218/
i have a doubt too

 

[hizirofaki]

Does anyone out there know how to solve this? :'(

Correct answer is A.

thetotal energy is 230000
from this - all the energy lost the remaining energy is 300
23000=100
300=?
cross ultiply

 

[Studydayandnight]

Can someone explain this question to me?

The answer is C.

 

[Studydayandnight]

thetotal energy is 230000
from this - all the energy lost the remaining energy is 300
23000=100
300=?
cross ultiply

Waittt, how does 23000 equal to 100? :s

 

[Jeezan]

http://theallpapers.com/papers/CIE/AS_and_ALevel/Biology (9700)/9700_s13_qp_11.pdf
Q.39 the answer is A
Isn't nitrogen fixation anaerobic ?

 

[nehaoscar]

Does anyone out there know how to solve this? :'(

Correct answer is A.

1st trophic level has 23000 J energy
energy transferred succesfully =
23000 - 8000 (lost) = 15000
15000 - 10500 = 4500
4500 - 4200 = 300

transferred energy divided by original input
= 300/23000 and multiply this by 100 to get % as 1.3%

 

[lara dalal]

What are the membranes exactly? The answer is D btw

 

[hizirofaki]

guys my question help plz https://www.xtremepapers.com/community/attachments/11160221_10204517600243144_750592502_n-jpg.53218/

 

[qwertypoiu]

View attachment 53196

Once a legumionous plant is planted...
And it dies...
There will be more nitrogen fixing bacteria, that will continue to live in the soil I think...
These will make NH4+...
These will be nitrified by nitrifying bacteria... So increase in them as well...
Decomposing bacteria will decompose the remains of leguminous plants...
I think the fixed nitrogen will be used by the crops, as usual. So perhaps denitrifying bacteria won't have any significant changes in its population size/.

 

[hizirofaki]

Once a legumionous plant is planted...
And it dies...
There will be more nitrogen fixing bacteria, that will continue to live in the soil I think...
These will make NH4+...
These will be nitrified by nitrifying bacteria... So increase in them as well...
Decomposing bacteria will decompose the remains of leguminous plants...
I think the fixed nitrogen will be used by the crops, as usual. So perhaps denitrifying bacteria won't have any significant changes in its population size/.

how to do this ??
https://www.xtremepapers.com/community/attachments/11160221_10204517600243144_750592502_n-jpg.53218/

 

[qwertypoiu]

View attachment 53207
Aren't there only 3
1. RBC
2. capillary membrane
3. alveoli membrane

But then its D :O how??

Already answered this before:
A level Biology: Post your doubts here!

 

[qwertypoiu]

View attachment 53214
Why is it B
I know it's passive but the body is infected by a snake bite so shouldn't it be natural ?

The horse did artificial active immunity... Or vaccination...
However we collected the antibodies and gave it to a human, this is artificial passive immunity...