A level Biology: Post your doubts here!

[Amy Bloom]

Not so clear, i dont think so.

same here

 

[Amy Bloom]

Yeah I didn't know I was supposed to draw that hump hehe. I don't understand what's an annotation , it means four tissue layers? because it's written two annotations to describe two tissues! thanks a lot for your opinion

Annotation is like label. here it is like "Label any two visible distinctive tissues" It meant one labelling for one tissue. it asked two. so only two labellings.

 

[Amy Bloom]

See, it is hard to explain but imagine u had 2 aminoacid, lets call them Red and Blue
we can make
red red
red blue
blue blue
blue red

So as u see, 2 x 2....!!

Be carefull, be cause red blue....isnt like blue red
as they sed in the question..either end with amino group (-NH2) or a carboxyl group (-COOH)

brother, why 2 x 2 in the e.g. you gave? i don't get it.

 

[PhyZac]

brother, why 2 x 2 in the e.g. you gave? i don't get it.

As u saw in the example i gave 4 different compositions which is made from 2 since 2 x 2 gives 4
and if we started with 3 aminoacid we wud get 9... 3 x 3
and so with 20 aminoacid we will get 400
I hope u got my point.

 

[cyclone94]

asak
plz help me wid d foll.topics
oxidative phosphorylation,ethanol and lactate pathway

 

[PhyZac]

asak
plz help me wid d foll.topics
oxidative phosphorylation,ethanol and lactate pathway

This is an amazing explanation for oxidative phosphorylation

watch all the different videos for the ATP really helpful

ethanol and lactate, i will look for it.

 

[cyclone94]

This is an amazing explanation for oxidative phosphorylation

watch all the different videos for the ATP really helpful

ethanol and lactate, i will look for it.

Jazakallah

 

[PhyZac]

Any One Having AS biology Notes Full AS Syllabus Comprehensive but summarized Form?

http://www.mediafire.com/?smfz60x62dw4by5
This is the cambridge biology study guide for AS and A2. Incase you dont have it, so amazing.

 

[Amy Bloom]

As u saw in the example i gave 4 different compositions which is made from 2 since 2 x 2 gives 4
and if we started with 3 aminoacid we wud get 9... 3 x 3
and so with 20 aminoacid we will get 400
I hope u got my point.

yeah got it thanks

 

[daredevil]

A sequence of amino-acids end in either an amino group (-NH2) or a carboxyl group (-COOH) . What is the theoretical number of chemically different dipeptides that may be assembled from 20 different amino acids?

A-40
B-80
C-160
D-400

400??

its (20)^2

 

[daredevil]

Yeah I didn't know I was supposed to draw that hump hehe. I don't understand what's an annotation , it means four tissue layers? because it's written two annotations to describe two tissues! thanks a lot for your opinion

an annotation is a step further than the labelling i.e. it is a small description.
normally when we are asked to annotate its mostly for xylem and phloem
like you write that it is an alternately arranged tissue and about its size and stuff that you can SEE.
If its not right then plz correct me here

 

[daredevil]

how to separate chloroplast pigments using chromatography... helppp!!!
Thanks in advance

it will be the same way you wud perform any other chromatography... as we studied in o levels too :
like put a drop of the sample (chlorophyll in this case) on the pencil line and immerse the chromatography paper in a suitable solvent [e.g. ethanol] just below the drop of sample.
IMP: - the sample drop SHOULD NOT touch the solvent directly.
as time passes the solvent travels up the chromatography paper. as it travels it takes the sample drop with it and separates the components along the way.

PS. it is not an official answer or some solid paper mein likhnay wala stuff so don't write it in the paper without having it proof-read with some authentic source
its just to make u understand what u have to do. if u have any confusions, feel free to ask

 

[PhyZac]

an annotation is a step further than the labelling i.e. it is a small description.
normally when we are asked to annotate its mostly for xylem and phloem
like you write that it is an alternately arranged tissue and about its size and stuff that you can SEE.
If its not right then plz correct me here

I heard that too, usually if coloured picture, we could even say as an example, xylem darker, phloem lighter in colour.
I am not sure though.

 

[daredevil]

I heard that too, usually if coloured picture, we could even say as an example, xylem darker, phloem lighter in colour.
I am not sure though.

yeah u r ryt. u can write that too. pretty much any visual description is acceptable.

 

[strangerss]

same here

I read the marking scheme and it's written one correct labeling from: then they included cortex XS

 

[Amy Bloom]

I read the marking scheme and it's written one correct labeling from: then they included cortex XS

Have a look at the examiners report too.

 

[Malik777]

https://www.xtremepapers.com/community/threads/your-maximum-score-in-biology-p1.24096/

 

[San_mk]

hi....im attachin notes for A2 energy and Respiration......msg me if u need notes on other chapters...........hope youll find them helpful.

 

[lyuchenqujoy]

There is a question in the pastpapers that says an enzyme will hydrolyze the hinge region of antibodies and break the antibodies into "3" fragments. How can they break into 3????? Shouldn't the antibodies break into 2 parts each contains one heavy chain and one light chain if hydrolysis occurs at the hinge region??

 

[PhyZac]

There is a question in the pastpapers that says an enzyme will hydrolyze the hinge region of antibodies and break the antibodies into "3" fragments. How can they break into 3????? Shouldn't the antibodies break into 2 parts each contains one heavy chain and one light chain if hydrolysis occurs at the hinge region??

I deleted my other post, because i think i did it wrong. Look at the reaction from the one top to the one below....this is the fragmentation occurring.