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(A) Low level of thyroxine leads to hypo...

(A) Low level of thyroxine leads to hypo- thyroidism.
(R) Thyroxine is an iodinated derivative of amino acid (tyrosine)

A

Both (A) and (R) are true and (R) is the correct explanation of (A)

B

Both (A) and (R) are true and (R) is not the correct explanation of (A)

C

(A) is true but (R) is false

D

Both (A) and (R) are false

Text Solution

Verified by Experts

The correct Answer is:
B
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Which of the following is a derivative of amino acid ?

Which of the following hormones is a derivative of amino acid?

(A) Glycine is essential amino acid. (R) Glycine is optically active alpha -amino acid

Study the following and choose the correct statements I)Hormones produced by adenohypohysis are protein hormones II)Hormones stores by neurohypophysis are peptide hormones III)Catecholamines are water soluble hormones IV)Thyroid hormone is derived from aminoacid the tyrosine

(A) Veronal and amytal are neurologically active drugs. (R) Veronal and amytal are derivatives of Barbituric acid.

Which of the following hormones is derived from a single amino acid?

(A) A low level of noradrenaline in the body causes depression. (R) Signal sending activity becomes low.

(A): HBr is stronger acid than HI. (R) : Bromine is more electronegative than iodine.

alpha - amino acids are high melting crystalline solids because of the zwitterion structure. They are moderately soluble in water. In acidic medium, alpha - amino acids exist as cations (I) and thus migrate towards cathode under the influence of an electric field. On the other hand, in alkaline medium, alpha - amino acids exist as anions (III) and thus migrate towards anode under the influence of an electric field. However, at some intermediate value of p^(H) , the concentration of the cationic form (I) and anionic form (III) will become equal and consequently the alpha - amino acid will exist primarily as the neutral dipolar ion (II). At this p^(H) , there would be no net migration of the amino acid in an electric field. This p^(H) at which there is no net migration of the amino acid under the influence of an applied electric field is called isoelectric point (pI). Each amino acid has a characteristic isoelectric point. The pH of an amino acid that does not have an ionisable side chain such as alanine isd average of pK_(a) values of the carboxyl group and the protonated amino group. H_(3)overset(+)(N)-overset("R")overset("|")("C")H-COOH overset(" "OH^(-)" ")underset(" "H^(+)" ")hArr H_(3)overset(+)(N)-underset("Zwitterion (II)")(overset("R")overset("|")("C")H)-COO^(-)overset(" "OH^(-)" ")underset(" "H^(+)" ")hArr underset((III))(overset(+)(N)-overset("R")overset("|")("C")H)-COO^(-) Further, the alpha - carbon of all the amino acids (except glycine) is chiral (asymmetric) and hence amino acids can exist in teo stereoisomeric forms i.e., D and L. However, all the nautrally occurring amino acids belong to the L - series. underset("L(-)Glyceraldehyde")(HO-overset("CHO ")overset("| ")underset(" "CH_(2)OH)underset("| ")("C ")-H)" " underset("L-Amino acid")(H_(2)N-overset("COOH")overset("| ")underset("R ")underset("| ")("C ")-H) In alanine, carboxyl group ionises at pK_(a1)=2.34 and ammonium ion at pK_(a2)=9.69 . The isoelectric point of the amino acid is at p^(H) .

AAKASH SERIES-BIOMOLECULES-OBJECTIVE EXERCISE-4 (ASSERTION (A) & REASON (R) TYPE QUESTIONS :)
  1. (A) Vitamin 'C' is ascorbic acid. (R) All acids are vitamins

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  2. (A) All hormone receptors are proteins, (R) All hormones are protein...

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  3. (A) Water soluble vitamins like ascorbic acid must be supplied regular...

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  4. (A) Vitamins are important in diet. (R) Deficiency of vitamins cause...

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  5. (A) Insulin is a steroidal harmone. (R) A steroid contains two five ...

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  6. (A) Vitamins are considered as essential food factors. (R) Most of th...

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  7. (A) Vitamins are to be supplimented to the body as an energy source. ...

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  8. (A) Deficiency of vitamin K causes excessive bleeding in injuries. (...

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  9. (A) Enzyme catalysed hydrolysis of sucrose is faster than acid catalys...

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  10. (A) Insulin is a globular protein. (R) Insulin has two polypeptide c...

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  11. (A) Low level of thyroxine leads to hypo- thyroidism. (R) Thyroxine ...

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  12. (A) Carbohydrate metabolism is controlled by gluco corticoids. (R) H...

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  13. (A) Enzymes are needed in large quantities for the progress of a react...

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  14. (A) Hormones are produced by endocrine glands in the body. (R) Hormo...

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  15. (A) The deficiency of vitamins causes specific diseases. (R) All vit...

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  16. (A) Taking excess vitamin pills are harmless. (R) All the vitamins a...

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  17. (A) Vitamins A, D, E and K are stored in liver and adipose tissues. ...

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  18. (A) 'B' group vitamins except B-12 cannot be stored in our body. (R)...

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  19. (A) Epinephrine and nm epinephrine are derivatives of polypeptides. ...

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  20. (A) B-complex vitamins and vitamin-C are not stored in the body. (R)...

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