A level Biology: Post your doubts here!

[Syed Umar]

I'd like to know more about drawing plan diagrams..

 

[My Name]

I'd like to know more about drawing plan diagrams..

What more..?
Maybe this has something.
https://www.xtremepapers.com/community/threads/biology-practical-notes.4718/

 

[silver slick]

Does anyone here know how to move the stage micromter on the microscope.... like how to move it? so that it can line with the the eye piece graticule??????

 

[qwertypoiu]

Does anyone here know how to move the stage micromter on the microscope.... like how to move it? so that it can line with the the eye piece graticule??????

Just like you move any specimen that is being inspected.... By using the controls on the microscope.

 

[HumptyR]

how can the intial rate reduce? if the active site doesnt change shape the initial activity of the enzyme in this case is not affected

As there is an inhibitor its harder for substrate to leave. So rate of reaction reduces

 

[silver slick]

Just like you move any specimen that is being inspected.... By using the controls on the microscope.

oh ok, so the round circular "noob" on the microscope also move the stage ? I have seen the videos mostly, showing how to adjust the specimen?I
anyway thank you for replying.. very kind of you

 

[qwertypoiu]

oh ok, so the round circular "noob" on the microscope also move the stage ? I have seen the videos mostly, showing how to adjust the specimen?I
anyway thank you for replying.. very kind of you

Yep!

 

[Lana19984]

10. Which of the following genotypes would produce the smallest number of different gametes if the alleles are assorted independently?
A) aa BB Dd
B) AA BB DD
C) Aa Bb DD
D) Aa BB DD
E) Aa Bb Dd

11. Which of the following processes can decrease the genetic variation in natural populations?
A) recombination B) immigration C) mutagenesis D) inbreeding E) hybridization

12. Which of the following structures present in the embryos of higher plants develops into primary leaves of seedlings?
A) epicotyl B) endosperm C) radicle D) hypocotyl E) cotyledon

can anybody please answer those and maybe explain ?

 

[qwertypoiu]

10. Which of the following genotypes would produce the smallest number of different gametes if the alleles are assorted independently?
A) aa BB Dd
B) AA BB DD
C) Aa Bb DD
D) Aa BB DD
E) Aa Bb Dd

11. Which of the following processes can decrease the genetic variation in natural populations?
A) recombination B) immigration C) mutagenesis D) inbreeding E) hybridization

12. Which of the following structures present in the embryos of higher plants develops into primary leaves of seedlings?
A) epicotyl B) endosperm C) radicle D) hypocotyl E) cotyledon

can anybody please answer those and maybe explain ?

10. B
11. D
12. E

 

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[Jessica :)]

http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_s15_qp_51.pdf

hey guys I need help with this paper question 1 b (i)

thanks!!!!!

 

[ali danish]

can someone explain this

 

[ali danish]

can some one explain this ASAP plss???

 

[Sariya Khan]

View attachment 60966 can some one explain this ASAP plss???

Q.2. As the question says that '4 different amino acids' you'll need 4 different tRNAs to carry those different aminoacids.. Since tRNA can be reused, we can have 4 tRNAs and still be able to translate mRNA. So the answer must be 'A'
14. As you must be familiar with the fact that cytosine combines with guanine and adenine with Uracil. If 20 % of bases are cytosine, the percentage of guanine must be the same i.e. 20. S the remaining total percentage is 60.. which is of adenine as well as thymine. Since they've got to be complementary base pairing, their percentage too will be the same i.e. 30! So when 30% of adenine will link up with mRNA nucleotides , 30 % of the bases in mRNA would be uracil

 

[ali danish]

Q.2. As the question says that '4 different amino acids' you'll need 4 different tRNAs to carry those different aminoacids.. Since tRNA can be reused, we can have 4 tRNAs and still be able to translate mRNA. So the answer must be 'A'
14. As you must be familiar with the face that cytosine combines with guanine and adenine with Uracil. If 20 % of bases are cytosine, the percentage of guanine must be the same i.e. 20. S the remaining total percentage is 60.. which is of adenine as well as thymine. Since they've got to be complementary base pairing, their percentage too will be the same i.e. 30! So when 30% of adenine will link up with mRNA nucleotides , 30 % of the bases in mRNA would be uracil

thanks alot do u have any idea about the 53rd question as well????

 

[Sariya Khan]

View attachment 60961
can someone explain this

The correct option has got to be B.
You can see in sample 4 that there is absence of the base 'C' when uracil is present. So the C can be thymine. Since the number of the B and C or B and uracil bases is the same, it can be deduced that the base 'B' is adenine.

 

[Sariya Khan]

thanks alot do u have any idea about the 53rd question as well????

You got it?

 

[ali danish]

You got it?

yess thanks alot it really helpedd

 

[shingiechingz@8]

View attachment 60968

 

[shingiechingz@8]

HELP