biochemistry ques from pilot exam

[fairy123]

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ques) Which of the following pairs of amino acids is expected to be found on the interior of a globular protein?
A-Lysine and arginine
B-Arginine and leucine
C-Leucine and valine
D-Valine and glutamic acid
D-Glutamic acid and lysine

it syas interior of globular protien,in interior there are always hydrobhobic n non polar amina acids present,so im confuse among B n C,can sombody solve the problem,
thankyou

 

[artlove]

ans is C
non polaramino acids: alanine
glycine
methionine
tryptophan
phenylalanine
proline
pls correct me if i am wrong.

 

[artlove]

and also branched chain amino acids are non polar. so answer might be option c.

 

[fairy123]

thankyou so much.

 

[skabbaraju]

ans is C
non polaramino acids: alanine
glycine
methionine
tryptophan
phenylalanine
proline
pls correct me if i am wrong.

How do u know methionine is non-polar.? It is polar because of the sulphur atom.
The one that you are missing might be isoleucine.

 

[artlove]

I refereed again. The answer is like that methionine is non polar.

 

[skabbaraju]

I refereed again. The answer is like that methionine is non polar.

Please refer to Dental Decks.
Thanks.

 

[Kash]

I refereed again. The answer is like that methionine is non polar.

Hi Artlove,

The right answer is leucine and valine.
because methionine is polar and also belongs to the thiol group. its clearly given in decks.
Skabbaraju is correct.

 

[artlove]

Hi
Methionine may have sulphur but doesnt have -SH (thiol) group like cysteine... _SH like -OH is a polar group...
Methionine has -S-CH3 which is non-polar.. it means that -S-CH3 is not available to form hydrogen bonds plus the CH3 will dilute the electronegativity of S atom through inductive effect.
I also saw dental decks but I have read standard biochem texts (Harper's Biochem) which mentions that methionine is non-polar.
Let me know if this still doesnt clarify.

 

[doc76]

Hi
Methionine may have sulphur but doesnt have -SH (thiol) group like cysteine... _SH like -OH is a polar group...
Methionine has -S-CH3 which is non-polar.. it means that -S-CH3 is not available to form hydrogen bonds plus the CH3 will dilute the electronegativity of S atom through inductive effect.
I also saw dental decks but I have read standard biochem texts (Harper's Biochem) which mentions that methionine is non-polar.
Let me know if this still doesnt clarify.

yup, artlove is right, methionine is non -polar

 

[smilydent]

ques) Which of the following pairs of amino acids is expected to be found on the interior of a globular protein?
A-Lysine and arginine
B-Arginine and leucine
C-Leucine and valine
D-Valine and glutamic acid
D-Glutamic acid and lysine

it syas interior of globular protien,in interior there are always hydrobhobic n non polar amina acids present,so im confuse among B n C,can sombody solve the problem,
thankyou

hello,
the answer c leucine and valine is correct coz they are hydrophobic which are present interiorly in any protien structure and thus nonpolar. regarding methionine it is a polar uncharged aminoacid, yes it has a sulphur and it is a part of s-adenosyl methionine[sam] which is a methyl donor in biochemical pathways, also cystiene has sulfur in it and can form disulfide bond which stabalizes the shape of the protien, SO methionine is a polar amino acid,
thanks

 

[fairy123]

A 20:1 ratio of base bicarbonate to carbonic acid(BB:CA) will,according to Henderson-hasselbatch equation,maintain acid-base balance and normal blood pH.Carbonic acid levels can be regulated by the respiratory system and bicarbonate ion by the kidneys.therefore disturbances in acid-base balance depend on the relative quantities of carbonic acid n base bicarbonate in the exracellular fluid.Two type of disturbances,metabolic and respiratory,can alter the proper ratio of these components.metabolic disturbance affect the bicarbonate element,and the respiratory disturnbances affect the carbonic acid element of the buffer pair.

here is the important board ques related to this statement.

if there is ratio of bicarbonate-carbonic acid is 20:1,after sometime it will be 10:1,what do u say it is
1-compensate alkalosis
2-compensate acidosis
3-uncompensate alkalosis
4-uncompensate acidosis

is anybody ans this.

 

[skabbaraju]

A 20:1 ratio of base bicarbonate to carbonic acid(BB:CA) will,according to Henderson-hasselbatch equation,maintain acid-base balance and normal blood pH.Carbonic acid levels can be regulated by the respiratory system and bicarbonate ion by the kidneys.therefore disturbances in acid-base balance depend on the relative quantities of carbonic acid n base bicarbonate in the exracellular fluid.Two type of disturbances,metabolic and respiratory,can alter the proper ratio of these components.metabolic disturbance affect the bicarbonate element,and the respiratory disturnbances affect the carbonic acid element of the buffer pair.

here is the important board ques related to this statement.

if there is ratio of bicarbonate-carbonic acid is 20:1,after sometime it will be 10:1,what do u say it is
1-compensate alkalosis
2-compensate acidosis
3-uncompensate alkalosis
4-uncompensate acidosis

is anybody ans this.

I would go with 4.

 

[smilydent]

A 20:1 ratio of base bicarbonate to carbonic acid(BB:CA) will,according to Henderson-hasselbatch equation,maintain acid-base balance and normal blood pH.Carbonic acid levels can be regulated by the respiratory system and bicarbonate ion by the kidneys.therefore disturbances in acid-base balance depend on the relative quantities of carbonic acid n base bicarbonate in the exracellular fluid.Two type of disturbances,metabolic and respiratory,can alter the proper ratio of these components.metabolic disturbance affect the bicarbonate element,and the respiratory disturnbances affect the carbonic acid element of the buffer pair.

here is the important board ques related to this statement.

if there is ratio of bicarbonate-carbonic acid is 20:1,after sometime it will be 10:1,what do u say it is
1-compensate alkalosis
2-compensate acidosis
3-uncompensate alkalosis
4-uncompensate acidosis

is anybody ans this.

yeah its true that in case of metabolic alkalosis the bicarbonate levels increases and in case of hyperventilation it is respiratory alkalosis in which carbonic acid increases, i think it would be compensate acidosis,coz metabolic acidosis compensates as respiratory alkalosis and metabolic alkalosis compensates as repiratory acidosis, hope it helps