A level Biology: Post your doubts here!

[My Name]

describe strucure of kidney section b of p4
i drew a kidney with pencil and labels in pencil will cie mark this

Is that all that you did?
Diagrams are accepted BUT not just diagrams.Diagrams can be used for reference.
You need to explain the structures in words also!

 

[qwertypoiu]

Maize, Zea mays, is a major cereal food crop. Unlike most crop plants, maize seed is
produced by hybridisation between two different inbred parental strains.
hybridisation means artifical selection in the context of above sentence???
between two different inbred parental strains.?? means what

I think it means this (please correct me if I'm wrong):

Let's say there is one group (strain) of identical plants that have been inbred (made to reproduce) over several generations. Their characteristics will be similar to one another after some time. We'll call this strain A.
Now there is a completely different group of plants that have undergone the same process of inbreeding (probably in a different part of the world). Their characteristics will be similar to each other. This is strain B.

Of course strain A and strain B will be different from each other in terms of genes, but when they were made to produce offspring, Maize was produced. That's it. There are certain advantages to it I think. (Like maybe having improved insect resistance)

 

[mohmed ahmed soliman]

I think it means this (please correct me if I'm wrong):

Let's say there is one group (strain) of identical plants that have been inbred (made to reproduce) over several generations. Their characteristics will be similar to one another after some time. We'll call this strain A.
Now there is a completely different group of plants that have undergone the same process of inbreeding (probably in a different part of the world). Their characteristics will be similar to each other. This is strain B.

Of course strain A and strain B will be different from each other in terms of genes, but when they were made to produce offspring, Maize was produced. That's it. There are certain advantages to it I think. (Like maybe having improved insect resistance)

but all belong to same species

 

[qwertypoiu]

but all belong to same species

Yes I think so

 

[mohmed ahmed soliman]

in mark scheme local circuits is always mentioned when a question is about transmission of nerve impulse along neurone
what is local circuits and what is its role

 

[mohmed ahmed soliman]

?

 

[mohmed ahmed soliman]

what is gentic drift and founder effect

 

[mohmed ahmed soliman]

15. organisms need energy, to stay alive / for metabolism / AW ;
16. ATP as, (universal) energy currency / described ;
17. light energy for photosynthesis ; A light dependent stage
18. light-dependent stage detail ;
19. light-independent stage detail ;
20. chemical energy ;
21. for anabolic reactions ;
22. named reaction; e.g. protein synthesis / starch formation
23. activation of glucose in glycolysis / described ;
24. active transport ;
25. detail; e.g. sodium - potassium pump /movement against a concentration gradient
26. mechanical energy / movement ;
27. detail ; e.g. muscle contraction / spindle
www.theallpapers.com
Page 14 Mark Scheme: Teachers’ version Syllabus Paper
GCE AS/A LEVEL – May/June 2012 9700 41
© University of Cambridge International Examinations 2012
28. temperature regulation ;
29. AVP ; e.g. bioluminescence / electrical discharge

help me to make a good answer

 

[Eugene99]

I have no idea at what point amino acid are hydrolyzed!

 

[My Name]

View attachment 59785
I have no idea at what point amino acid are hydrolyzed!

See in you know what one amino acid looks like right?
Likethis:

Here you have three joined by condensation reaction in which water molecule is removed.
Now in this question you need to see where if you add water will it give you a structure as shown in the figure above.
The answer would be 2 and 4.

Did you understand my explanation?

 

[Eugene99]

See in you know what one amino acid looks like right?
Likethis:

Here you have three joined by condensation reaction in which water molecule is removed.
Now in this question you need to see where if you add water will it give you a structure as shown in the figure above.
The answer would be 2 and 4.

Did you understand my explanation?

INdeed I do understand, thanks a lot
but wait, what will happen to NH when hydrolysis occur, seems like an H will combine with N and OH will combine C=O, am i right?

 

[qwertypoiu]

INdeed I do understand, thanks a lot
but wait, what will happen to NH when hydrolysis occur, seems like an H will combine with N and OH will combine C=O, am i right?

When an amide group (CONH) is hydrolysed, the C=O part joins with OH to form COOH (a carboxylic acid) and the NH part joins with H to form NH2 (an amine group)

 

[Eugene99]

When an amide group (CONH) is hydrolysed, the C=O part joins with OH to form COOH (a carboxylic acid) and the NH part joins with H to form NH2 (an amine group)

thank you

 

[mohmed ahmed soliman]

Is that all that you did?
Diagrams are accepted BUT not just diagrams.Diagrams can be used for reference.
You need to explain the structures in words also!

i want help in simple and serial dilution p5

 

[My Name]

i want help in simple and serial dilution p5

Oh yes you needed notes right? Or was it some question? Im sorry Ive been/am busy.
http://abacus.bates.edu/~ganderso/biology/resources/dilutions.html
^ This site originally shared by qwertypoiu has great explanation for SERIAL and SIMPLE dilution.Ignore the rest and dont worry about the dilution factore and ul thing.
If youre going to give P3 also then check this video

For P5 just remember that your explanation needs to be clear as possible.
Diagrams can be drawn for reference.
Be sure to state the type of dilution youre using an add the concentration and volume value.
Do include the correct units.
Mention the apparatus used.
If you include explanation or procedure for 1 or 2 concentration preparation you can add a line like: use this method like so and so for preparing a range of concentrations...

If anyone else wants to add points.Reply to this.Thanks.

 

[0101as]

can someone please help me with biology p5 ?
i'll be very grateful if anyone can share any notes, tips or techniques to solve p5 question's.
thanks

 

[My Name]

can someone please help me with biology p5 ?
i'll be very grateful if anyone can share any notes, tips or techniques to solve p5 question's.
thanks

https://www.xtremepapers.com/community/threads/biology-paper-5-tips.27105/
Welcome

 

[mohmed ahmed soliman]

auxin and apical dominance is that included in sy

 

[My Name]

auxin and apical dominance is that included in sy

You can check here http://www.cie.org.uk/images/164500-2016-2018-syllabus.pdf
The last page has all the parts that have been removed.

I know for sure that....role of auxin in elongation growth is there!

 

[Eugene99]

Please explain... how are 4 tRNA molecules needed? (A)