Biology MCQ thread..!!

[Xthegreat]

Help plz!!

5?

 

[aliya_zad]

Can anyone help me with these doubts? viewtopic.php?f=26&t=9440

Thank you.

As for the 18th one i guess the ans is A.Each Trna consists of 1 amino acid and in this case there asking the MINIMUM no of amino acids req for 4 diff kinds, so it has to be 4. It can be 10 as well, bt u see the question's asking for the min no.

7) a dipeptide consists of 2 amino acids. In this case there are 12 diff types of aminoacids. Each amino acid can be a possibility out of 12, and since there are 2 amino acids it will be a possibility out of 12x12=144. ans=C

24) i think the ans is 20. as only 20 different kinds of aminoacids exist and hence 20 trna's.

 

[Ahmad95]

Can anyone help me with these doubts? viewtopic.php?f=26&t=9440

Thank you.

As for the 18th one i guess the ans is A.Each Trna consists of 1 amino acid and in this case there asking the MINIMUM no of amino acids req for 4 diff kinds, so it has to be 4. It can be 10 as well, bt u see the question's asking for the min no.

7) a dipeptide consists of 2 amino acids. In this case there are 12 diff types of aminoacids. Each amino acid can be a possibility out of 12, and since there are 2 amino acids it will be a possibility out of 12x12=144. ans=C

24) i think the ans is 20. as only 20 different kinds of aminoacids exist and hence 20 trna's.

THANK YOU! I finally got it! This is my "teacher's" second year teaching Biology AS and whenever I asked him about those all he says is: "I'm not sure.. but it's only one mark so it's no problem." I swear to God whenever he says that I want to slap him across the face. Excuse my aggression.

Could you possibly explain the others? Thank you again.

 

[aliya_zad]

i'll post it in dat thread..

 

[Xthegreat]

No one answered these questions PLZ answer them i need them Thanxx
I want for the following questions plz. :
1- J10/11 23. What is the minimum no. Of base substitutions required to change the nucleotice sequence of the HbA allele to the HbS allele?
A. 1 B. 2 C. 3 D.4
why it is A??
2- J10/11 no. 8 why it is D ????
3- no. 27 in the same exam .....
4- N05/01 no. 37 why it is B ???
Plz i want explanations for the answers as i no the answers and i will be thankful!!
Sry for not posting pics of the questions here
thx in advance

1. it only takes 1 change in the nucleotide sequence to form the sickle cell.
- sickle is different from the normal red cells by 1 amino acid.
- 3 nucleotides codes for 1 amino acid
- but 1 change in the nucleotide sequence is enough to change the amino acid.

2. A. is wrong, who told you amylose is branched?
B. it says the breakdown of amylose and amylopectin, doesn't tell why they should be joined together
C. is just wrong
D. is the only possible answer. cause when they both join together they become insoluble.amylopectin is soluble on it's own.

3. well it's A because it will disrupt the cohesion between water molecules is the main reason.
B. wrong, root pressure is affected by the water potential in the root cells
C. translocation occurs in the phloem
D. root hair cells depend on the concentration of ions

4. the answer is really C. i don't know where and how you get B.
but when antibody break at the hinge region, u get 3 fragments. 2 light chains and 1 heavy chains.
so 2.

 

[aliya_zad]

Can anyone help me with these doubts? viewtopic.php?f=26&t=9440

Thank you.

As for the 18th one i guess the ans is A.Each Trna consists of 1 amino acid and in this case there asking the MINIMUM no of amino acids req for 4 diff kinds, so it has to be 4. It can be 10 as well, bt u see the question's asking for the min no.

7) a dipeptide consists of 2 amino acids. In this case there are 12 diff types of aminoacids. Each amino acid can be a possibility out of 12, and since there are 2 amino acids it will be a possibility out of 12x12=144. ans=C

24) i think the ans is 20. as only 20 different kinds of aminoacids exist and hence 20 trna's.

ahmed, for the 7th one we considered it to be 12^2 coz 2 aa made from 12 diff kinds. As for the 13th one its the same as r aa made from n diff kinds of aa, so itz n^r.
Sinceit was given in terms of n and r i gt kinda confused.

 

[minnienerd]

can anybody post a biology tropical study guide plzz.. i need them soon !!!..thanx in advance

 

[ninjas4life]

can someone explain whly the answer is a??

 

[aliya_zad]

Cz u see there is no increase/decrease in the sizeof the strip. One is folded( i mean like curved), while the other is not folded.

 

[naelmizan1994]

The leaf in diagram 1 is rolled up, showing that it has lost water by osmosis becoming flaccid. hence the solutionin 1 is more concentrated and the solution in 2 is dilute (less negative water potential of Y). the leaf in 2 gains water by osmosis and hence it's water potential is also higher (less negative) than that of 1.

 

[URVASHI]

@ urvashi i have answers in my booklet which question u want telme...

need answers for Q6, 14, 30 n 26. Ive solved the paper n i find these q. confusing. thanks.

 

[EzioAuditre]

WINTER 2003 Q.25 ANS IS A..!
SUMMER 2008 Q.27 ANS IS C.!

but both the questions r same????

 

[hassam]

dude SOLUTE POTENTIAL is hell different from SOLUTE CONC....one ER of practicals said that solute potential is the same as water potential so rememba this fact

 

[lychee26]

Can you explain it ?

 

[sweetiepie]

@ urvashi i have got marking scheme here u go ...

 

[arsimme]

@ urvashi i have got marking scheme here u go ...

which year mark scheme is it ?

 

[lychee26]

GUYS WHAT'S THE DIFFERENCE BETWEEN SOLUTE POTENTIAL AND SOLUTE CONCENTRATION ?

 

[sweetiepie]

itx o/n 2002 cant u c...

 

[icanhelp]

lychee26...............hope this helps



solute concentration is the amount of solute in a given volume of solvent

solute potential is the amount by which presence of THAT solute lowers the water potential in a the given volume of solvent. Therefore solute potential

depends on solute concentration. More solute means the solution become more negative hence solute potential is high. Low solute means water potential is

more positive so solute potential is low.....

pls click thanks if u understood or else ask me again

-icanhelp

 

[MHHaider707]

Hey can anyone please help me in O/N 04 P1 Q.38

Here's the link:

http://www.xtremepapers.me/CIE/Internat ... 4_qp_1.pdf


And in O/N 05 Q.27

http://www.xtremepapers.me/CIE/Internat ... 5_qp_1.pdf