A level Biology: Post your doubts here!

[My Name]

how do we know the maximum length of the organelle?
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s12_qp_13.pdf
question_4
plz

Question 4 says:
What are always present in prokaryote cells? A capsules B flagella C pili D ribosomes

 

[My Name]

23) Answer is C because the main function of DNA polymerase is to copy one molecule of double-stranded DNA into two new double stranded DNA molecules
27) Answer is A because sucrose in phloem is always transported from source to sink, so uploading from source should be 1st step and unload the last one

Sorry ... I meant variant two http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w09_qp_12.pdf

 

[Lola_sweet]

Sorry ... I meant variant two http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w09_qp_12.pdf

Ya Allah Mn xD
i was just gonna comment

 

[Lola_sweet]

Sorry ... I meant variant two http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w09_qp_12.pdf

Qs number again

 

[My Name]

Ya Allah Mn xD
i was just gonna comment

Sorry,sorry.

Qs number again

23 and 27

 

[Lola_sweet]

Sorry,sorry.

23 and 27

its okay
check ur wall

 

[My Name]

 

[jason kwon]

Question 4 says:
What are always present in prokaryote cells? A capsules B flagella C pili D ribosomes

Sorry i accidentally uploaded s12 paper.
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w12_qp_13.pdf
Question 4 please

 

[My Name]

Sorry i accidentally uploaded s12 paper.
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w12_qp_13.pdf
Question 4 please

No prob,I accidentally gave the wrong varaint.XD
Ohkay so..you know the formula Magnification=Size of Image/Size of Object.
In the question magnification is ×20 000.You can get the size of Image by using the diagram.I got it as 60mm which is 60,000µm
Place the values in the formula
60,000µm/×20 000 = 3
So the answer is B which is 3 × 10^0µm.

 

[SadiaMaryam]

View attachment 57122
View attachment 57123

I've read somewhere that it is normal for cell to lose some amount of telomeric DNA in each round of cell division...and furthermore, when the telomere length is dropped to a critical point, a signal is given to stop further cell division.
So, it seems like a normal cell division will need something to replace telomere to carry on replication, therefore Answer A is the correct one.
For the next question: When the sister chromatids separate at the centromere, approaching the opposite poles, distance between chromatids and poles decreases----->stage is anaphase. Distance between centromeres of the sister chromatids increases as they are leaving each other, going away from each other. So the answer is A I guess, I didn't check MS

 

[My Name]

I've read somewhere that it is normal for cell to lose some amount of telomeric DNA in each round of cell division...and furthermore, when the telomere length is dropped to a critical point, a signal is given to stop further cell division.
So, it seems like a normal cell division will need something to replace telomere to carry on replication, therefore Answer A is the correct one.
For the next question: When the sister chromatids separate at the centromere, approaching the opposite poles, hence distance between chromatids and poles decrease----->stage is anaphase. Distance between centromeres of the sister chromatids increases as they are leaving each other, going away from each other. So the answer is A I guess, I didn't check MS

I checked the MS both answers are A.
I guess I should read more.
Thanks!

 

[My Name]

 

[My Name]

 

[Winx132]

View attachment 57127

answer is A right?
Because since it said keh DNA has 120 nucleotides so then MRNA has only 60 nucleotides.
And 3 codon code for 1 protien so the number of amino acids would be of 20 i.e 60 / 3 .
Hope it answers

 

[Winx132]

View attachment 57128

C answer?
If the answer is C then because the data says that the bacteria was allowed only ONCE to replicate in medium with N 14 .So Alla the DNA molecules that were N15 before would all have their complementart base pairing with N14 necloetides

 

[SadiaMaryam]

View attachment 57127

Double stranded DNA contains 120 nucleotides. During transcription, only one strand will be transcripted, so one strand of DNA contains 60 nucleotides. mRNA will also contain 60 nucleotides. Each amino acid contains a trilplet code of 3 bases (nucleotides). So no. of amino acids in the 60-nucleotide-long polypeptde will be : 60/3=20 amino acids

 

[My Name]

answer is A right?
Because since it said keh DNA has 120 nucleotides so then MRNA has only 60 nucleotides.
And 3 codon code for 1 protien so the number of amino acids would be of 20 i.e 60 / 3 .
Hope it answers

Double stranded DNA contains 120 nucleotides. During transcription, only one strand will be transcripted, so one strand of DNA contains 60 nucleotides. mRNA will also contain 60 nucleotides. Each amino acid contains a trilplet code of 3 bases (nucleotides). So no. of amino acids in the 60-nucleotide-long polypeptde will be : 60/3=20 amino acids

Ty!

 

[Winx132]

Ty!

YOur most welcome but what about the other question? was i right?0.0

 

[My Name]

C answer?
If the answer is C then because the data says that the bacteria was allowed only ONCE to replicate in medium with N 14 .So Alla the DNA molecules that were N15 before would all have their complementart base pairing with N14 necloetides

Yes it is C.But I don't understand.

 

[My Name]

YOur most welcome but what about the other question? was i right?0.0

Yes you were.
But I dont get the reason behind the answer.