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A level Biology: Post your doubts here!

_MoHD_E

_MoHD_E

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A41905 said:
9700/12/m/j/12

21. Which statements about tRNA structure are correct?

1. There is a binding site for the attachment of a specific amino acid, as well as a different binding site for the attachment to the ribosome, in order to allow translation to occur.
2. There is a ribose-phosphate backbone with strong covalent phosphodiester bonds and areas within the polynucleotide chain where base-pairing by hydrogen bonding occurs.
3. There is a section known as an anticodon that contains the same triplet of bases as the triplet of DNA bases that has been transcribed to produce the mRNA codon.

A. 1 only
B. 1 and 2 only
C. 2 and 3 only
D. 1, 2 and 3

The answer given is B. Can anyone explain why the third statement is incorrect?
Thank you in advance :)
Click to expand...
Because it doesn't contain the same triplet as DNA well most of the times yes but sometimes no where there is thymine involved for example if the gene of the DNA coding for a specific polypeptide has the first triple as ATG then tRNA will be AUG as there is no thymine In tRNA
 
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lfjnsldf

lfjnsldf

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How do you all like, is there any easy way to remember the size of the cell organelles?
 
W

wizzzzzzzzzzzzzzzzz

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السلام عليكم و رحمت الله و براكاته
I have bio practical exam after tom
Did anyone get an A if so can you give me tips so I can get an A and is it really hard to get an A as they say
 
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wizzzzzzzzzzzzzzzzz said:
السلام عليكم و رحمت الله و براكاته
I have bio practical exam after tom
Did anyone get an A if so can you give me tips so I can get an A and is it really hard to get an A as they say
Click to expand...
mariiqur said:
I have one the day after tomorrow too
i also need tips since I reallyyy need to get an A.
Click to expand...
Waalikumasalam warahmatuallah wabarakatuhu

I did not get an A yet.
But I think I can give you a few tips.

First things first,dont forget to say Bimillah. Read the question carefully.
Try your best not to panic.
There are always questions that you can do without carrying our any experiment if you can then do these first.
Also they usually have a graph that you need to plot.Make sure it is neat,has scale mentioned for both axes clearly.Include the labels on axis along with appropriate units.
When solving questions related to magnification be sure to put the correct units.
For observing your result you need to make a table,draw the table before starting the experiment.
wizzzzzzzzzzzzzzzzz said:
Nice inshallah we will do good
Btw did u take p22
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In sha Allah
wizzzzzzzzzzzzzzzzz said:
Btw do u rrmember p22 questions
Click to expand...
You can check the thread here:https://www.xtremepapers.com/community/threads/how-was-9700_w15_p22.42426/
 
qwertypoiu

qwertypoiu

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My Name said:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w12_qp_35.pdf
Help me with this XD
question 2 part b i
Click to expand...
The question looked familiar because I asnwered someone else a few months ago, so I'm just copy-pasting. (Sorry if it isn't exactly the same )

Whenever there is a question like this, the small width lines are the eye piece graticule. The bigger lines are the stage micrometer.
Step 1: 1 eyepiece graticule unit = 0.01 divided by 4 = 0.0025mm
(this is because I know one width of stage micrometer is 0.01mm. I can SEE that there are around FOUR eyepiece graticule units that fit into one of these stage micrometer line gaps)

Step 2: 0.0025mm multiplied by 1000 = 2.5 micrometer.
(just conversion piece of cake :) )
 
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qwertypoiu said:
The question looked familiar because I asnwered someone else a few months ago, so I'm just copy-pasting. (Sorry if it isn't exactly the same )

Whenever there is a question like this, the small width lines are the eye piece graticule. The bigger lines are the stage micrometer.
Step 1: 1 eyepiece graticule unit = 0.01 divided by 4 = 0.0025mm
(this is because I know one width of stage micrometer is 0.01mm. I can SEE that there are around FOUR eyepiece graticule units that fit into one of these stage micrometer line gaps)

Step 2: 0.0025mm multiplied by 1000 = 2.5 micrometer.
(just conversion piece of cake :) )
Click to expand...
Which question is this?
Thanks though.
 
qwertypoiu

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My Name said:
Which question is this?
Thanks though.
Click to expand...
Sorry the numbers are different. Here's an edited version:

Whenever there is a question like this, the small width lines are the eye piece graticule. The bigger lines are the stage micrometer.
Step 1: 1 eyepiece graticule unit = 0.1mm divided by 25 = 0.004mm
(this is because I know one width of stage micrometer is 0.1mm. I can SEE that there are around TWENTY--FIVE eyepiece graticule units that fit into one of these stage micrometer line gaps)

Step 2: 0.004mm multiplied by 1000 = 4 micrometer.
(just conversion piece of cake :) )


The previous answer was the answer to variant 3 instead:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w12_qp_33.pdf

Have a look and see if you can do it :)
 
M

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qwertypoiu said:
Sorry the numbers are different. Here's an edited version:

Whenever there is a question like this, the small width lines are the eye piece graticule. The bigger lines are the stage micrometer.
Step 1: 1 eyepiece graticule unit = 0.1mm divided by 25 = 0.004mm
(this is because I know one width of stage micrometer is 0.1mm. I can SEE that there are around TWENTY--FIVE eyepiece graticule units that fit into one of these stage micrometer line gaps)

Step 2: 0.004mm multiplied by 1000 = 4 micrometer.
(just conversion piece of cake :) )


The previous answer was the answer to variant 3 instead:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w12_qp_33.pdf

Have a look and see if you can do it :)
Click to expand...
I got it Alhamdulillah.
How many marks do we loose if its not exact?
 
qwertypoiu

qwertypoiu

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My Name said:
TWO...scary!
I did this question and I got like 4.2 instead of 4 :/ but in that teacher did give me marks.
In sha Allah.
Pray for me.Im tensed about the microscope part!
Click to expand...
Actually if it's just the numerical error it should be a mark only :)
May Allah help you. It'll be easy In Shaa Allah.
Manage your time well. Don't Panic.
Plz pray for me as well I'll pray for you

Microscopes are not too difficult. There's drawing. Labelling. And the theoretical part:

A level Biology: Post your doubts here!
 
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qwertypoiu said:
Actually if it's just the numerical error it should be a mark only :)
May Allah help you. It'll be easy In Shaa Allah.
Manage your time well. Don't Panic.
Plz pray for me as well I'll pray for you
Click to expand...
Alright.
In sha Allah!
Yes, I really have to try my best not to panic.Sigh.
Yes,sure In sha Allah. Jazakallah Khair!
 
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