A level Biology: Post your doubts here!

[qwertypoiu]

Oopsee I completely forgot to change that.
There won't be any RBC but some WBC can squeeze through.I myself had a doubt about whether phagocytes will be there or not.
Thank you btw for reminding me! I'll edit that post ASAP.
Thank you it took a lot of time,but I didn't EXACTLY type it all I copied the question from past paper ( but obviously added some things).
Best of Luck!

Oh actually I'm not sure if phagocytes exist in tissue fluid. I know WBCs can, but maybe they're only lymphocytes... So yeah not sure about it.

 

[My Name]

TRANSPORT IN MAMMALS
EDIT:There is a mistake in the notes
"What does tissue fluid contain?
Platelets and protein concentration low as compared to plasma But NO phagocytes"

The tissue fluid is almost identical to the composition of plasma.However, it contains less proteins molecules than plasma as they are too large to escape through the tiny gaps.
Although RBCs are not present some WBCs may squeeze through.

POST EDITED PLEASE CHECK

 

[My Name]

Oh actually I'm not sure if phagocytes exist in tissue fluid. I know WBCs can, but maybe they're only lymphocytes... So yeah not sure about it.

Yes check my post now I added a note. ( even I have a doubt)
If you find anymore mistakes do let me know ASAP!

 

[hizirofaki]

Yes check my post now I added a note.
If you find anymore mistakes do let me know ASAP!

hey is there a way i can chat with u ??

 

[My Name]

hey is there a way i can chat with u ??

What is it going to be about?
Your wall would be fine I think.

 

[hizirofaki]

What is it going to be about?
Your wall would be fine I think.

just some help in p1

 

[My Name]

just some help in p1

Its better you post your doubts here the other members can also help you.
I might not be able to answer all questions and might not have a lot of time.
Post your doubts here the members and I will help you as much as possible.

 

[hizirofaki]

Its better you post your doubts here the other members can also help you.
I might not be able to answer all questions and might not have a lot of time.
Post your doubts here the members and I will help you as much as possible.

k

 

[hizirofaki]

http://maxpapers.com/wp-content/uploads/2012/11/9700_s08_qp_1.pdf
q6 why Y?/??

 

[Lola_sweet]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w14_qp_11.pdf

q3) why they ve circular DNA?

 

[My Name]

http://maxpapers.com/wp-content/uploads/2012/11/9700_s08_qp_1.pdf
q6 why Y?/??

blue with Benedict’s reagent -tells us that it does not have glucose( meaning no X present so it can't be A)

purple with biuret -tells us that it has proteins( meaning it has W so it can't be D)

and cloudy with ethanol - tells us that it has fats/lipid ( meaning Z is there for sure so it can't be C)

So the answer is B.

 

[Bba321]

Any good notes on Bio p5????

 

[lara dalal]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w14_qp_11.pdf

q3) why they ve circular DNA?

Mitochondria and Chloroplast have 70S ribosome and circular DNA just like prokaryotes as they are thought to have been independent prokaryotes that entered the body/plant and became a part of the cell.

 

[qwertypoiu]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w14_qp_11.pdf

q3) why they ve circular DNA?

That's like saying why do they have 70S ribosomes...
The current theory is known as the endosymbioant theory. Basically it is thought that mitochondria and chloroplasts used to be prokaryotes, that established a mutualism with ancestors of current eukaryotes.
Thus they still have their smaller ribosomes, along with the circular DNA.

 

[My Name]

Any good notes on Bio p5????

Hey you can check this thread
https://www.xtremepapers.com/community/threads/biology-paper-5-tips.27105/

 

[lara dalal]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_s13_qp_11.pdf
Why is q39 A? Doesnt Nitrogen fixation need anaerobic conditions?

 

[My Name]

May june 2013 p12 q21 pl expl

Check this post
https://www.xtremepapers.com/commun...st-your-doubts-here.9858/page-242#post-910331
Credits to qwertypoiu

 

[qwertypoiu]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_s13_qp_11.pdf
Why is q39 A? Doesnt Nitrogen fixation need anaerobic conditions?

I'm guessing cuz I'm bad at ecology...
Nitrogen fixation done by NITROGENASE requires anaerobic conditions, and in legumes the bacteria in root nodules are provided with the anaerobic conditions by the plant having a substance in the nodules called leghaemoglobin, which effectively mops up all the oxygen. Because it absorbs it all.
So the condition in soil can be aerobic.

 

[qwertypoiu]

Guys, how we do solve this??

I NEED to do well enough to get atleast a 30 in paper 1 :'( which seems almost impossible! -_-

How do we solve the 4th one?

Measure the distance, divide by 2500.

 

[qwertypoiu]

P12 may 2012 q1 explain

C.
D is too large, a thousand micrometer is 1mm!
That would mean we would be able to see cells with naked eyes!
10 to 100 micrometer range is correct, seeing as one of the largest cells in humans is the egg cell, which may have diameter of 0.1mm. (which is 100 micrometer. It is important to learn the sizes!)
You'd not choose B and definitely not A, because you know mitochondria have size of one micrometer.