A level Biology: Post your doubts here!

[MYLORD]

someone help me with this one
and the answer is B.....WHY ?

 

[Farhad221]

I guess you read the wrong Que
It is the last question part b

Well as the question says keystone species are those whose disappearance can change the whole food chain all you have to do.is repeat this and state the effect of loosing seaotters. Like which species will increase as seaotters are gone and which will decrease as their predators have increased in numbers.As you can see the numbers of all species will change state changes in at least three with the definition of keystone species and you will get all 4 marks.

 

[Farhad221]

change in ionic

That's question 5 b the member wants 6 part b.
Btw what is chqngedionic.

 

[qwertypoiu]

someone help me with this one
View attachment 52974 and the answer is B.....WHY ?

Look carefully at all the molecules, count the + charges and - charges. For there to be an overall charge, either there is more + than - or there is more - than +.
Alanine and glycine both have same number of + and -. So they are uncharged.

 

[MYLORD]

Look carefully at all the molecules, count the + charges and - charges. For there to be an overall charge, either there is more + than - or there is more - than +.
Alanine and glycine both have same number of + and -. So they are uncharged.

thnx

 

[nehaoscar]

People got any ideas on the topics and questions that may come up on this year's paper?
variant 22 please

 

[MYLORD]

Look carefully at all the molecules, count the + charges and - charges. For there to be an overall charge, either there is more + than - or there is more - than +.
Alanine and glycine both have same number of + and -. So they are uncharged.

and also this one
answer is A ....Why?

 

[Mahnoorfatima]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w14_qp_11.pdf
Question 29? There's no diagram in Mary Jones book showing the labelling of smooth muscles trachea e.t.c? How am I supposed to recognize it?
Question 40? UGHHH I HATE ECOLOGY.

 

[Mahnoorfatima]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w14_qp_12.pdf
QUESTION 6 ANYONE?

 

[MYLORD]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w14_qp_11.pdf
Question 29? There's no diagram in Mary Jones book showing the labelling of smooth muscles trachea e.t.c? How am I supposed to recognize it?
Question 40? UGHHH I HATE ECOLOGY.

 

[Studydayandnight]

Can someone explain this, please?? Correct answer is A!

 

[MYLORD]

 

[Awesome12]

Can someone explain this, please?? Correct answer is A!

During moderate exercise, one breathes more heavily to supply more O2 to respiring cells and as quickly as possible. Thus we know that the tidal volume will increase. Note that X is the DISTANCE between the maximum and the crest on the wave. It is NOT THE AMPLITUDE OF THE WAVE. Thus if the tidal volume will increase, the amplitude of the wave will also increase and hence the distances X and Y will decrease.

 

[nehaoscar]

and also this one
View attachment 52979 answer is A ....Why?

Firstly you should understand that the 2 strands represent the 2 complementary strands of DNA
4 T's in 2nd strand means due to complementary base pairing there should be 4 A's in first strand...
The total number of base pairs are 15
so 15 nucleotides on each strand
we have on strand 1
A = 4
C = 6
T = 3
Add them gives 13
15 - 13 = 2
So 2 G's

 

[Laibaaa]

Someone please explain the role of B and T lmphocytes properly as i am really confused and am mixing them up

also transcription and translation

please

 

[qwertypoiu]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w14_qp_11.pdf
Question 29? There's no diagram in Mary Jones book showing the labelling of smooth muscles trachea e.t.c? How am I supposed to recognize it?
Question 40? UGHHH I HATE ECOLOGY.

Is the answer to ecology question A?

 

[Mahnoorfatima]

Is the answer to ecology question A?

I thought it was A as well but it's D idk why!?

 

[qwertypoiu]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9700_w14_qp_12.pdf
QUESTION 6 ANYONE?

Should be C. Xylem always on top in a leaf transverse section.
Since palisade layer double in thickness than spongy layer it must be C.

 

[My Name]

I though I should share this
http://biology4alevel.blogspot.com/

 

[qwertypoiu]

Someone please explain the role of B and T lmphocytes properly as i am really confused and am mixing them up

also transcription and translation

please

B-cells secrete antibodies. T-cells stimulate B cells, and kill our body cells that have become infected.

Transcription = DNA to mRNA.
Translation = mRNA to polypeptide.