AS Biology P1 MCQs Preparation Thread

[xyz!]

june 09 / p1 / q22
june 10 / p11 / q3

m/j/09 ==> it is obvious dat if semi-conservative replications takes place den the % of cells containing N15 will decrease and N14 will increase.
so v hav to curves with a decrease in % cells containing N15...the answer can't b D bcos if the 2nd generation has 50% cells den the 3rd generation wont directly reduce to 0%...there will b sum cells atleast wid say hybrid DNA(containing both N15 and N14)...so dat means der r sum cells containing N15...thus the answer is C and not D....got it?

N i dont noe the other question...

 

[biba]

m/j/09 ==> it is obvious dat if semi-conservative replications takes place den the % of cells containing N15 will decrease and N14 will increase.
so v hav to curves with a decrease in % cells containing N15...the answer can't b D bcos if the 2nd generation has 50% cells den the 3rd generation wont directly reduce to 0%...there will b sum cells atleast wid say hybrid DNA(containing both N15 and N14)...so dat means der r sum cells containing N15...thus the answer is C and not D....got it?

N i dont noe the other question...

thnx

 

[xyz!]

which of the following cell components contain mRNA?
1. chloroplasts
2. mitochondria
3.nucleus
4.rough ER

 

[Soulgamer]

june 09 / p1 / q22
june 10 / p11 / q3

Post links? No ones gonna do khuwari to go and individually find your paper.

 

[Soulgamer]

which of the following cell components contain mRNA?
1. chloroplasts
2. mitochondria
3.nucleus
4.rough ER

Is it 4?

 

[rogue94]

which of the following cell components contain mRNA?
1. chloroplasts
2. mitochondria
3.nucleus
4.rough ER

All 4 of them do

 

[raamish]

All 4 of them do

how does mitochondria and chloroplast contain mrna

 

[mhalvi]

https://fbcdn-sphotos-a.akamaihd.ne...6933426535_664491534_12390334_548868376_n.jpg

Can anyone explain why the answer is B and not A ?

(Red blood cell question)

THANK YOU

SODIUM 'IONS' THEY ARE HYDROPHILIC SO THEY CANT PASS THROUGH PHOSPHOLIPIDS THEY CAN ONLY GOO THROUGH CHANNEL PROTEIN THROUGH FACILITATED DIFFUSION...HOPE YOU GET IT

 

[rogue94]

how does mitochondria and chloroplast contain mrna

both mitochondria and chloroplasts contain 70S ribosomes for protein synthesis, and since mRNA is required for translation so....
I am not sure about chloroplasts, but mitochondria also contain DNA and transcription (formation of mRNA) takes place in mitochondria.

 

[xyz!]

All 4 of them do

ya dat is wt d markscheme says bt how cum mRNA in present in all of dem? i thot its only present in the nucleus....

 

[rogue94]

ya dat is wt d markscheme says bt how cum mRNA in present in all of dem? i thot its only present in the nucleus....

RER have ribosomes as protein synthesis takes place in RER, hence they have mRNA (required for translation). Ribosomes and DNA are also present within mitochondria and chloroplasts so both transcription and translation takes place in these two organelles.

 

[xyz!]

RER have ribosomes as protein synthesis takes place in RER, hence they have mRNA (required for translation). Ribosomes and DNA are also present within mitochondria and chloroplasts so both transcription and translation takes place in these two organelles.

oooooo....ok thnx!

 

[JulyMei]

Yes, correct.

Oh! Okok!! Thanks a lot! I just mixed that.. that's why i answered hydrogen bond. LOL. Thanks!!

 

[Knight]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s11_qp_11.pdf
Q; 14 and 33

 

[Soulgamer]

Oh! Okok!! Thanks a lot! I just mixed that.. that's why i answered hydrogen bond. LOL. Thanks!!

No problem. Happens to the best of us.

 

[Ineedhelp]

A protein contains all the common amino acids.
What would be the hypothetical minimum number of types of tRNA molecules needed for the
synthesis of this protein?
A) 3
B) 4
C) 20
D) 64

how do you work this out?

 

[Ineedhelp]

7 What is the theoretical number of chemically different dipeptides that may be assembled from 12
different types of amino acids?
A 24 B 72 C 144 D 400

this too..
and question 4 from this paper : http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s04_qp_1.pdf

 

[rogue94]

A protein contains all the common amino acids.
What would be the hypothetical minimum number of types of tRNA molecules needed for the
synthesis of this protein?
A) 3
B) 4
C) 20
D) 64

how do you work this out?

there are 20 common amino acids, and since each type of tRNA molecules carries/binds to, only a specific amino acid, 20 tRNA molecules are needed (for 20 amino acids).

 

[rogue94]

7 What is the theoretical number of chemically different dipeptides that may be assembled from 12
different types of amino acids?
A 24 B 72 C 144 D 400

this too..
and question 4 from this paper : http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s04_qp_1.pdf

For the 1st question the answer is C (144). The working is: 12^2 = 144. Here 12 is the no. of different amino acids and 2 is the no. of amino acids in the chain (its a dipeptide so, 2 amino acids).
For question 4 the answer is C. Lysosomes contain most of the hydrolytic enzymes as it is their function to digest/break down, a wide variety of substances (such as organelles and bacteria).

 

[The King XII]

View attachment 11918
It's A bro.... Anyone else wanna give a try??

Well ummm beans are leguminous plants so nitrogen fixation (mutual relation ship e.g rhizobium bacteria) is going to occur and MORE nitrate ions "eventually" are produce in the soil so more wheat productivity so apparently its not B, C and D, C and D are definitely going to introduce more nitrate ions in to the soil, just look back at the nitrogen cycle so this leaves A, growing other cereal crops (which are non-leguminous plants) is there going to be any omission or addition of nitrate ions to the soil? NO so no increase in the productivity of cereal crops hope you got it.